R. Marino, N. Tzankova Dintcheva, F.P. La Mantia LLDPE/caly/compatibilizers nanocomposites: rheological behaviour under shear and non-isothermal elongational flow

New phosphazene-based chain extenders containing allyl and epoxide groups

In this paper we present the synthesis and the characterization of cyclophosphazenes substituted with allyl groups, their transformation in epoxide-containing cyclophosphazenes and the final utilization of these compounds as chain extenders in combination with polyamides. The reaction at high temperature of Nylon-6 with epoxy-functionalized cyclophosphazenes leads to the opening of the epoxy units by the action of both amino (--NH2) and carboxylic (--COOH) end-groups of the polymer to enhance the final molecular weight of this material. The consequences of this fact on the thermal, mechanical and visco-elastic properties of treated Nylon-6 have been also evaluated and compared to those of t…

Selective localization of organoclay and effects on the morphology and mechanical properties of LDPE/PA11 blends with distributed and co-continuous morphology

Morphology modification of polymer-filled nanocomposites subjected to non-isothermal elongational flow

Heat-Resistant Fully Bio-Based Nanocomposite Blends Based on Poly(lactic acid)

Poly(lactic acid) (PLA) is melt mixed with polyamide 11 (PA11) to obtain a heat-resistant fully bio-based blend with PLA as the dominant component. The goal is achieved by adding small amounts of organoclay (OMMT), which is used to manipulate the blend microstructure. The selective positioning of the OMMT inside the PA11 and at the PLA/PA11 interface turns the blend morphology from drop/matrix into co-continuous at high PLA content (70 wt%). The OMMT-rich PA11 framework that interpenetrates the major PLA phase effectively contributes to bear stresses, and the nanocomposite blend keeps its structural integrity up to ≈160 °C, i.e., about 100 °C above the PLA glass transition.

Film blowing of modified polyethylene

Silanol-POSS as dispersing agents for carbon nanotubes in polyamide

Silanol polyhedrad oligomeric silsesquiosane terminated with phenyl rings (phPOSS) has been considered as dispersing agent for carbon nanotubes (CNTs) in polyamide (PA) matrix. Two different approaches have been followed for the introduction of the phPOSS molecules: a “classical” approach which involves the introduction of the dispersing agent during the melt mixing, and an “innovative” approach, consisting in the immobilization, either covalent and non-covalent, of phPOSS molecules onto CNTs surface. The properties of PA-based nanocomposites, containing free phPOSS molecules and phPOSS molecules immobilized onto the CNTs outer surface, have been evaluated through rheological, mecha…

Thermo-oxidative stabilization of poly(lactic acid) with antioxidant intercalated layered double hydroxides

Two antioxidant modified layered double hydroxides (AO-LDHs) were successfully prepared by the intercalation of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid (IrganoxCOOH) and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) in the layered structure of LDH. It was found that by anchoring the phenolic moieties to the LDH layers the antioxidant power is retained in the case of Trolox, and even amplified in the case of IrganoxCOOH. A small amount of the two AO-LDHs was incorporated into poly(lactic acid), PLA, by solution mixing and melt extrusion. The thermo-oxidative stability of the composites was compared with that of the neat PLA and PLA containing free AOs. SEC analy…

Stabilizzazione

Film Nanocompositi Polimerici

Role of oxyegen on rheological response of polyethylene–clay nanocomposites to annealing

Film blowing of silane-modified polyethylene

The grafting of vinyltriethoxysilane (VTES) onto polyethylene (PE) with the help of small amounts of peroxides was investigated to film-blow these modified materials. The degree of crosslinking was kept very low to achieve good melt processability and improved mechanical properties. The possibility of obtaining modified PE films with improved properties and regularly distributed crosslinking with a single processing step demonstrates the uniqueness of this study. The additive concentration was established through preliminary studies; with a batch mixer, it was possible to process the modified PE in the film-blowing operation. Water treatment of the modified films after film blowing allowed …

Clay-based polymer nanocomposites: photoxidation and stabilisation

Polyethylene–clay nanocomposite: Effect of annealing under different atmospheres

Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping

In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold-drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation…

Morphology modification of a polyethylene/clay nanocomposite samples under convergent flow

The morphology of PE/CL nanocomposite samples subjected to convergent flows is studied. Elongational flow – the typical flow involved in spinning and film-blowing processing operations – significantly increases with the reduction of the capillary diameter. The values of the convergent extensional stress (calculated by Cogswell's formula) for the PE/CL systems, for all the adopted capillary geometries, are greater than the calculated values for pure polyethylene. The applied convergent flow, at the entrance of the capillary, is able to change the clay morphology and consequently the final material properties on the PE/CL system with limited affinity between the matrix and organo-modified cla…

Structure-properties relationships of polyhedral oligomeric silsesquioxane (POSS) filled PS nanocomposites

The polyhedral oligomeric silsesquioxane (POSS) additivated polystyrene (PS) based nanocomposites were pre- pared by melt processing and the structure-properties relationships of the POSS-PS systems were compared to those of the neat PS. In order to investigate the effect of these structural parameters on the final properties of the polymer nanocompos- ites, five different kinds of POSS samples were used, in particular, POSS with different inorganic cage and with different organic pendent groups. The rheological investigation suggests clearly that the POSS acts as a plasticizer and that the processability of the PS was positively modified. The affinity between the POSS samples and the PS ma…

Durability of advanced nanocomposites based on polyethylene oxide and nanodiamonds

Nanodiamonds nanoparticles (NDs) are amongst the most promising materials for multifunctional nanocomposites for various applications

Amino acid-based cholinium ionic liquids as sustainable catalysts for pet depolymerization

Chemical recycling to monomers is one of the key strategies in tackling the issues deriving from persistent plastic pollution in the environment, and poly(ethylene terephthalate) (PET) is among the most used polymers in modern society. In this context, we herein describe the glycolysis of PET to bis-hydroxyethyl terephthalate (BHET), promoted by basic cholinium salts differing for the anions, also comprising amino acid anions. We investigated the optimal reaction conditions, finding that the best-performing catalyst is [Ch][Gly], in the presence of which a conversion of 85% and a yield of 51% are achieved at 150 °C after 6 h, from PET deriving from a clear water bottle. We used our protocol…

Improvement of the photo-stability of nanocomposite based LDPE/EVA films

Rheological behaviour of PAN-based electrolytic gel containing tetrahexilammonium and magnesium iodide for photoeletrochemical applications

LLDPE/caly/compatibilizers nanocomposites: rheological behaviour under shear and non-isothermal elongational flow

Towards functional nanotubes through grafting of antioxidant molecules onto the surface of MW-CNTs: an innovative approach in the characterization

Polyolefin/clay nanocomposite drawn fibres with and without compatibilizer: structural analyses and mechanical performance

Effetto del flusso elongazionale su sistemi nanocompositi a matrice polimerica e silicati: morfologia e proprietà meccaniche

Photo-oxidation and improving of the photo-resistance of LLDPE based nanocomposites

Photo-stability of LDPE/EVA – based nanocomposite films

PROCESSING AND CHARACTERIZATION OF THE POLYMER/CNTs NANCOMPOSITE FIBRES.

Innesto di catene polimeriche sulla superficie di nanotube di carbonio mediante reazione di accoppiamento radicalico

La modifica di nanotubi di carbonio (CNT) attraverso innesto (grafting) di catene polimeriche sulla loro superficie è un metodo efficace per promuovere la dispersione di queste cariche a livello nanometrico in una matrice polimerica. La funzionalizzazione covalente di CNT con catene polimeriche viene generalmente ottenuta sia attraverso crescita controllata di polimeri a partire dalle pareti della nanocarica mediante metodi "grafting from" sia attraverso metodi di "grafting to" che si basano sulla reazione di condensazione tra polimeri preformati e CNT opportunamente modificati. In questo lavoro viene proposto un nuovo approccio di tipo "grafting to" per innestare catene polimeriche su CNT …

Nanocompositi da Polietileni e Copolimeri PE-g-MA con Diversa Struttura Molecolare

Predicting the photoageing and photostabilization of polymer nanocomposites

Morfologia e proprietà di nanocompositi a base di poliammide e CNTs: effetto della geometria e della funzionalizzazione superficiale

Photooxidative behaviour of polyethylene/polyamide-6 blends

International audience; The photochemical behaviour of several polyethylene/polyamide-6 blends was studied under conditions of artificial accelerated weathering. Particular attention was paid to five different compositions ranging from pure polyethylene to pure polyamide with blends of PE/PA-6 of various compositions: 75/25, 50/50 and 25/75 wt/wt%. Analysis by infrared spectroscopy of the chemical modifications caused by photooxidation showed that exposing the polyethylene/polyamide-6 blends to UV-light irradiation led to the formation of oxidation photoproducts in both polymer phases. In agreement with both the mechanical and spectroscopic analyses, the photooxidation rate of the blends wa…

Morphology and Properties of Polyethylene/Clay Nanocomposite Drawn Fibers

The influence of an elongational flow on the morphology of PE/clay nanocomposite drawn fibers was studied. An increase of the elastic modulus and the tensile strength as well as a decrease of the elongation at break are observed with increasing draw ratio. The applied elongational gradient orients the polymer chains and the clay particles along the spinning direction. When the applied flow results in the formation and the orientation of exfoliated nanoparticles, a pronounced increase of the mechanical properties is observed. The dispersed clay particles can be broken and oriented by the extensional flow, which might indicate a flow induced intercalated/exfoliated morphology transition.

Clay nanocomposites based on functionalized polyethylene. Effect of the clay modifier and the preparation conditions

Effetto della Polarità dei Componenti sulle Proprietà di Nanocompositi

Thermo-oxidative resistant UHMWPE-based nanocomposites containing hybrid-nanoparticles based on natural anti-oxidants and carbon nanotubes

The use of natural antioxidants is an attractive way to formulate nanocomposites with extended durability and with potential applications in bio-medical field. In this work, Vitamin E (VE) in the form of α-tocopherol and Quercetin (Q) were physically immobilized onto multi-walled carbon nanotubes bearing covalently-linked long-chain alkyl ester groups (CNTs) and the resulting hybrids CNTs-VE and CNTs-Q were used to formulate thermo-oxidation stable ultra high molecular weight polyethylene based nanocomposites. The thermo-oxidation of the nanocomposites was performed at 120°C in air oven. The samples were then subjected to FTIR analyses at different annealing times. The accurate analysis of …

Green composites of organic materials and recycled post-consumer polyethylene

High barrier properties HDPE/PA6/MMT Films-Preliminary rheological and morphological studies

POSS Grafting on Polyethylene and Maleic Anhydride-Grafted Polyethylene by One-Step Reactive Melt Mixing

This study reports the one-step reactive melt mixing preparation of organic–inorganic hybrid based on maleic anhydride-grafted polyethylene and 3-(2-aminoethyl)aminopropyl-heptaisobutyl substituted polyhedral oligomeric silsesquioxane, (NPOSS), as well as on low-density polyethylene and allyl-heptaisobutyl-POSS (1POSS) in dicumyl peroxide presence, which is believed to activate the unsaturation of the reactive functional group of POSS itself. The successful grafting of POSS molecules onto polymeric backbones was probed through rheological and spectroscopic analysis. Grafting of POSS molecules enhances their dispersion in the polymeric matrix as shown by morphological analysis. Moreover, the…

Novel organo-modifier for thermally-stable polymer-layered silicate nanocomposites

A new novel approach for the stabilisation of polymer-clay nanocomposites has been investigated based on reacting chemically an antioxidant function, a hindered phenol moiety, with an organic modifier based on a quaternary ammonium salt. The chemically linked antioxidant-containing organic modifier (AO-OM) was then introduced into natural montmorillonite (MMt) through a cation-exchange reaction resulting in antioxidant-containing organo-modified clay (AO-OM-MMt). The new antioxidant-containing modified clay, along with other organo-modified clays having a similar organo-modifier but without the reacted antioxidant, were characterised by spectroscopic, thermogravimetric and x-ray diffraction…

Morphology modification in nanofilled polymer based systems upon shear and elongational flow

Compositi Verdi con Polietilene Riciclato e Cariche Organiche

Polymeric micelles as a new generation of anti-oxidant carriers

A promising strategy to immobilize a natural stabilizer in polymeric films is presented. Par-Ticularly, nevadensin (N, a natural basil flavonoid) molecules have been encapsulated in Pluronic F-127 micelles [F127, a triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)] and the obtained nanoparticles have been introduced in poly(ethylene glycol), PEG [otherwise known as poly(ethylene oxide), PEO]. In order to verify the effectiveness of the micelles as anti-oxidant carriers, PEG-based films have been subjected to artificial weathering. The encapsulation of anti-oxidant molecules allows the enhancement of N solubility in PEG, leading to advanced materials with enh…

Progress in Understanding of the Interactions between Functionalized Polyolefins and Organo-Layered Double Hydroxides

The dispersion of organo-layered double hydroxides (O-LDH) in functionalized polyolefins (POs) is investigated. Two different polyethylene matrices (maleic anhydride (MAH) and diethyl maleate functionalized) are tested and a hydrogenated fatty acid modified LDH is used. The attention is focused on evidencing the interaction between the functional groups of the polymer and the O-LDH through FT-IR. Moreover, a combination of solvent fractionation, morphological, and rheological characterizations enables to gain a deeper insight into the structure of these composites. In particular, the formation of bridging bonds between the particles and MAH functionalized macromolecules is assumed, possibly…

Understanding the Effects of Crosslinking and Reinforcement Agents on the Performance and Durability of Biopolymer Films for Cultural Heritage Protection

In the last two decades, the naturally occurring polysaccharides, such as chitosan and pectin, have gained great attention having potential applications in different sectors, from biomedical to new generation packaging. Currently, the chitosan and pectic have been proposed as suitable materials also for the formulation of films and coatings for cultural heritage protection, as well as packaging films. Therefore, the formulation of biopolymer films, considering only naturally occurring polymers and additives, is a current challenging trend. This work reports on the formulation of chitosan (CS), pectin (PC), and chitosan:pectin (CS:PC) films, also containing natural crosslinking and reinforce…

Effect Of Adding An Organically Modified Clay To A Polyamide/Polyethylene Blend In The Presence Of Compatibilizing Agents

Morfologia e proprietà di sistemi nanocompositi poliammide/CNTs e poliammide/carbon black sottoposti a stiro elongazionale

Nanocompositi a base di polistirene e ossido di zinco: azione disperdente delle molecole POSS

E-beam cross-linking of LDPE-OMMT nanocomposites and their photo-oxidation behaviour

Photo-oxidation behaviour of polyethylene/multi-walled carbon nanotube composite films

Pro-Degradant Activity of Naturally Occurring Compounds on Polyethylene in Accelerate Weathering Conditions

In this work, naturally occurring compounds, such as Vitamin E (VE) and Ferulic Acid (FA), at high concentrations, have been considered as pro-degradant agents for Low Density Polyethylene (PE). However, all obtained results using the naturally occurring molecules as pro-oxidant agents for PE have been compared with the results achieved using a classical pro-oxidant agent, such as calcium stearate (Ca stearate) and with neat PE. The preliminary characterization, through rheological, mechanical and thermal analysis, of the PE-based systems highlights that the used naturally occurring molecules are able to exert a slight plasticizing action on PE and subsequently the PE rigidity and crystalli…

The role of filler type on the photo-oxidation behaviour of micro- and nano-filled polypropylene

Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.

The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behavio…

Supramolecular Hydro- and Ionogels: A Study of Their Properties and Antibacterial Activity.

Diimidazolium-based organic salts, bearing peptides or amino acids as anions have been synthesised and tested for their gelling ability in biocompatible solvents. These low molecular weight salts were successfully used as gelators in phosphate buffered saline (PBS) solution and ionic liquids. Then, the properties of the obtained soft materials were analysed in terms of melting temperature and gel strength as accounted for by rheological investigations. The gel-phase formation was studied by using UV/Vis and resonance light scattering measurements, whereas the morphology of the soft materials was analysed by using polarised optical microscopy and scanning electron microscopy. To get informat…

Annealing time dependent rheological properties of polyethylene based nanocomposites

Thermally-stable polymer-layered silicate nanocomposites through intercalation of novel organo-modifier

Tunable radical scavenging activity of carbon nanotubes through sonication

Abstract Carbon nanotubes (CNTs) having controlled radical scavenging activity have been achieved tuning the content of their lattice defects induced by an ultra-sound (us) treatment. The reactivity of CNTs, subjected to ultra-sonication for different time intervals, toward 1,1-diphenyl-2-pycryl (DPPH) and hydroxyl (•OH) radicals has been estimated and related to defect concentration, evaluated through Raman spectrometry. The radical scavenging efficiency of ultra-sound treated CNTs (us-CNTs) increases with increasing the content of the structural defects, suggesting that the defect resulting from us treatment can be capitalized to obtain an amplified and controlled radical scavenging activ…

Effect of elongational flow on morphology and properties of Polymer/CNTs nanocomposite fibres

Influence of the matrix on photo-oxidative degradation of polyolefin based nanocomposite films

Biochar Particles Obtained from Agricultural Carob Waste as a Suitable Filler for Sustainable Biocomposite Formulations

In the context of sustainable and circular economy, the recovery of biowaste for sustainable biocomposites formulation is a challenging issue. The aim of this work is to give a new life to agricultural carob waste after glucose extraction carried out by a local factory for carob candy production. A pyrolysis process was carried out on bio-waste to produce biofuel and, later, the solid residual fraction of pyrolysis process was used as interesting filler for biocomposites production. In this work, biochar particles (BC) as a pyrolysis product, after fuels recovery of organic biowaste, specifically, pyrolyzed carobs after glucose extraction, were added on poly(butylene-adipate-co-terephthalat…

Structure and dynamics of polyethylene/clay films

The relationships between structure and rheology of polyethylene/clay hybrid composite blown films were investigated through rheological tests both in shear and elongational flow. Two polymer matrices (low density polyethylene, LDPE and linear low density polyethylene, LLDPE) with different relaxation kinetics were used. Independently from the matrix, morphological analyses (TEM, XRD, and SEM) indicate that the hybrid structures are similarly constituted of delaminated platelets or tactoids having a relevant degree of orientation along the draw direction. This strongly affects the rheological behavior of materials. However, despite the similarities emerged from morphological analyses, both …

Morphology and mechanical properties of nanofilled polymer blends

POSS Grafting on Polyethylene and Maleic Anhydride-Grafted Polyethylene by One-Step Reactive Melt Mixing

This study reports the one-step reactive melt mixing preparation of organic-inorganic hybrid based on maleic anhydride-grafted polyethylene and 3-(2-aminoethyl)aminopropyl-heptaisobutyl substituted polyhedral oligomeric silsesquioxane, (NPOSS), as well as on low-density polyethylene and allyl-heptaisobutyl-POSS (1POSS) in dicumyl peroxide presence, which is believed to activate the unsaturation of the reactive functional group of POSS itself. The successful grafting of POSS molecules onto polymeric backbones was probed through rheological and spectroscopic analysis. Grafting of POSS molecules enhances their dispersion in the polymeric matrix as shown by morphological analysis. Moreover, the…

Self thermostabilizing tocopherol-CNT/UHMWPE nanocomposites

Photo-oxidation behaviour of micro- and nano-filled polypropylene: effect of the filler type and compatibilizer precursor

Photo-oxidation behaviour of composite polyethylene/MW-CNTs

Effect of the nanotube aspect ratio and surface functionalization on the morphology and properties of multiwalled carbon nanotube polyamide-based fibers

In this study, the effect of the carbon nanotube (CNT) aspect ratio and surface functionalization on the mechanical behavior and morphological changes of polyamide (PA)-based fibers was investigated. Composites were prepared by the melt blending of CNTs with PA, and at a later time, the fibers were prepared by melt spinning and cold drawing. A reinforcement effect was noticed for all of the CNTs samples, and the increase in the mechanical properties and dimensional stability was more pronounced for highly oriented filaments. When the elongational flow was increased, the orientation of CNTs along the fiber direction was observed, but the nanotube alignment was much more difficult for CNTs wi…

Quercetin as natural stabilizing agent for bio-polymer

The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. Th…

A Review of Bioplastics and Their Adoption in the Circular Economy

The European Union is working towards the 2050 net-zero emissions goal and tackling the ever-growing environmental and sustainability crisis by implementing the European Green Deal. The shift towards a more sustainable society is intertwined with the production, use, and disposal of plastic in the European economy. Emissions generated by plastic production, plastic waste, littering and leakage in nature, insufficient recycling, are some of the issues addressed by the European Commission. Adoption of bioplastics–plastics that are biodegradable, bio-based, or both–is under assessment as one way to decouple society from the use of fossil resources, and to mitigate specific environmental risks …

Photo-oxidation behaviour of polystyrene-block-polybutadiene-block-polystyrene /CNTs nanocomposites

Polyamide 11/clay nanocomposites: Effect of extrusion, thermo- and photo-oxidation behavior

Photo-oxidation resistance of polyethylene/carbon nanotubes composites: aspect ratio and surface functionalization effect

Thermo-mechanical degradation of LDPE based nanocomposites

The role of organoclay in the morphology modification and in the properties in polyethylene/polyamide blend systems

Morphology and properties of polyamide/CNTs nanocomposite fibres

On the use of natural inorganic materials as fillers for recycled post-consumer ploastics

Advanced nano-hybrids for thermo-oxidative-resistant nanocomposites

In the present work, trisilanol phenyl polyhedral olygomeric silsesquiosane (TSPh-POSS) has been physically immobilized onto carbon nanotubes (CNTs) bearing covalently linked Br-terminated long-alkyl chain (Br-alkyl-f-CNTs), and the so obtained hybrid nanoparticles (Br-alkyl-f-CNTs/TSPh-POSS) have been used to prepare ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites with enhanced thermo-oxidative resistance. The effective immobilization of the TSPh-POSS molecules has been confirmed by spectroscopic and thermo-gravimetric analyses. Besides, the influence of the hybrid nanoparticles on the rheological and mechanical behaviour and morphology of the nanocomposites have bee…

EVA-montmorillonite nanocomposites: effect of processing condition

The aim of this study is to examine the effect of the compounding apparatus and of processing conditions on the properties of an organoclay-poly[ethylene-co-(vinyl acetate)] (EVA) nanocomposite. The filled materials were prepared using either a discontinuous batch mixer, a single screw extruder, a counter rotating intermeshing twin-screw compounder or a corotating intermeshing twin-screw extruder. The characterization of the obtained nanocomposites was performed by XRD, thermogravimetry, mechanical and rheological measurements. The study has shown the possibility of producing nanocomposites based on EVA and a commercial organoclay (Cloisite 15A) by several mixing equipments. In fact all the…

Molecular Dynamic Simulation on Polyamide6/Graphene nano-layers nanocomposites

In this work results obtained from Molecular Dynamic Simulation (MDS) on Polyamide 6 (PA6) chains in graphene containing nanocomposites are presented. Through detailed MDS, the interface of complex nanocomposites systems can be fully characterized, furthermore different physical properties, such as density, end-to-end distance , and average radius of gyration of polymers chains can be predicted. This issue is useful for the design of highly value-added nanocomposites and the optimization of their production process, by defining transformation steps and status variables (temperature, time and pressure), that can also help the industrial production.

Recycling ground tire rubber (GTR) scraps as high-impact filler of in situ produced polyketone matrix

A sustainable procedure for recycling powdered rubber coming from scrap tires (ground tire rubber [GTR]) is proposed as based on the dispersion in polyketone (PK) matrix, obtained in situ by CO/ethylene copolymerization. Three types of catalysts are used operative in solvents of different polarities. The catalyst productivity and the hybrids morphology are evaluated and optimized to final composites features. The obtained products are characterized by scanning electron microscopy, atomic force microscopy, and solvent extractions in order to investigate the occurrence and the extent of interactions between PK macromolecular chains and the GTR components; and their effects on the final proper…

Relazione struttura-proprietà in nanocompositi POSS-PS

Fibre a base di poliammide e nanotubi di carbonio: proprietà e morfologia

Effect of extrusion and photo-oxidation behaviour on polyamide11/clay nanocomposites

Effect of organoclay on morphology and properties of bio-based blends of Poly(lactic acid) and Polyamide 11

Photochemical stabilization of linear low-density polyethylene/clay nanocomposites: Towards durable nanocomposites

International audience; This article reports a study of the chemical modifications of LLDPE/nanoblend nanocomposites exposed to UV light in conditions of artificially accelerated ageing and natural weathering. Analysis by infrared spectroscopy of the chemical modifications produced by photoageing shows that the presence of an organo-clay leads to the decrease of the oxidation induction time of the polymer (LLDPE), which results in lower durability of the nanocomposites. Protection against photooxidation was tested with different kinds of UV stabilizers and with a metal deactivator. It is shown that the metal deactivator is very efficient in stabilizing the nanocomposite since it totally can…

Assessment of pro-oxidant activity of natural phenolic compounds in bio-polyesters

Abstract In this work, natural phenolic compounds, such as Vanillic Acid (VA), Ferulic Acid (FA) and Thymol (Th), at very high concentrations, have been considered as pro-oxidant agents for Polylactic acid (PLA). Specifically, thin films of neat PLA and PLA-based systems containing 2 and 3 wt% of VA, FA and Th have been produced and subjected to accelerated degradation in different environmental conditions. Preliminary characterizations, through rheological, mechanical, optical and morphological analysis, of the formulated PLA-based systems show that the VA and FA, even less the Th, are able to exert a plasticizing action during the processing and subsequently, the PLA crystallinity and rig…

Nanocompositi a base di copolimero stirene-butadiene-stirene e nanotubi di carbonio: morfologia e proprietà

On the Role of Extensional Flow in Morphology and Property Modifications of MWCNT/Polyamide-Based Fibers

Unfilled and MWCNT-filled PA fibers are prepared and the effect of the extensional flow on their mechanical performance and morphological variations is investigated. Morphological analyses using SEM, TEM, and SAXS suggest a stronger orientation of the MWCNTs along the fiber direction with increasing extensional flow. A particular MWCNT bundle formation in the PA drawn nanocomposite fibers is observed for the first time, and a pull-out of the central nanotube in some bundles is noted. The maintenance of the "shish-kebab" structure upon extensional flow is responsible for the mechanical improvements and dimensional stability in MWCNT-filled PA fibers.

Influence of the morphology on the photo-oxidation behaviour of polymer based nanocomposites

Formulation of agricultural films by using of the recycled polymers: resistance to the photo-oxidation

Photo-oxidation behaviour of composite polyethylene/MW-CNTs films

Modification of viscoelastic properties of polyethylene based nanocomposites after thermal treatment

Influence of antioxidants intercalated layered double hydroxides (AO-LDHs) on the thermo-oxidative stability of pla and pe based nanocomposites

Layered double hydroxides (LDHs) are excellent host matrices for storage and delivery of antioxidants (AOs).

Thermal treatment dependent rheological properties of polyethylene based nanocomposites

Injection moulding of recycled polyethylene-natural organuc fillers composites

Morphology and properties of CNTs and carbon black filled polyamide fibres

Morfologia e proprietà di fibre polimero/CNTs

Rheological Behaviour of polyolefin based nanocomposites in isothermal and non-isothermal elongational flow

Comparative Study of Different Maleic Anhydride Grafted Compatibilizer Precursors toward LDPE/PA6 Blends: Morphology and Mechanical Properties

The study deals with the effectiveness of maleic anhydride grafted styrene-b-ethylene-co-propylene copolymer (SEPMA) as compatibilizer precursor (CP) for blends of low density polyethylene (LDPE) with polyamide-6 (PA). The CP was produced by grafting MA onto SEP in the melt. The specific interactions between the CP and the blends components have been investigated through characterizations of the binary LDPE/CP and PA/CP blends. The compatibilizing efficiency of the MA-grafted SEP, as revealed by the thermal properties and the morphology of the compatibilized blends, has been shown to be excellent. The morphology, as well as the mechanical properties of the compatibilized with SEPMA 75/25 w/…

Carbon nanotubes-based nanohybrids for multifunctional nanocomposites

In the present work, nano-hybrids based on carbon nanotubes (CNTs) bearing immobilized, either through covalent linkage and physical absorption, commercial anti-oxidant molecules have been formulated and used as nanofillers in Ultra High Molecular Weight Polyethylene (UHMWPE), aiming at preparing multifunctional nanocomposites. The effective immobilization of the anti-oxidant molecules has been probed by spectroscopic and thermogravimetric analyses. The study of the morphology and the rheological behaviour of the nanocomposites show that the immobilization of anti-oxidant molecules onto the CNTs surface is beneficial for the state of the polymer/nanoparticles interfacial region. Additionall…

Polymer electrolytes based on PAN and mixed salts for photoelectrochemical appilcations: formulation and characterization

On the role of extensional flow in morphology and properties modifications in MW-CNTs and carbon black polyamide-based fibres

Apparecchiatura per la misura della deformazione sotto carico

EFFETTO DI NANO-ARGILLE ORGANO-MODIFICATE E COMPATIBILIZZANTI SULLE PROPRIETA’ DI NANOCOMPOSITI A BASE DI LLDPE

Using matrix-assisted laser deposition/ionization time-of-flight mass spectrometry for the characterization of fucntionalized carbon nanotubes

Polyolefin based nanocomposites: a method to achieve better dispersion of nanoclays in PE films and improve their physical properties

Thermo-Mechanical Degradation of LDPE-Based Nanocomposites

Thermo-mechanical degradation of LDPE-based nanocomposites was studied by mainly investigating the rheological properties. For all of the investigated processing conditions, the viscosity of the nanocomposites was higher than that of the pure-LDPE matrix, but on increasing the severity of the mixing conditions, the difference between the viscosity of the nano-filled polymer and that of the pure LDPE decreased. The X-ray traces of the nanocomposites suggest that intercalation has been achieved during the melt, when less-severe processing conditions were used. At severe processing conditions (longer mixing time, high temperature and shear stress) the thermo-mechanical degradation was accelera…

Immobilization of natural anti-oxidants on carbon nanotubes and aging behavior of ultra-high molecular weight polyethylene-based nanocomposites

The use of natural antioxidants is an attractive way to formulate nanocomposites with extended durability and with potential applications in bio-medical field. In this work, Vitamin E (VE) in the form of α-tocopherol and Quercetin (Q) are physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs). Afterward, the CNTs-VE and CNTs-Q are used to formulate thermally stable ultra high molecular weight polyethylene based nanocomposites. The obtained results in the study of the thermo-oxidation behavior suggest a beneficial effect of the natural anti-oxidant carbon nanotubes systems. The unexpected excellent thermo-resistance of the nanocomposites seems to be due to a syne…

Rheological behaviour of PAN-based electrolytic gel for photoeletrochemical applications

LDPE/PA6/compatibilizer films: mechanical and rheological behaviour

The role of elongational flow in morphology modification of Polyethylene/OMMT nanocomposite system

Polyethylene/clay nanocomposite: morphology and mechanical properties modification under convergent flow

Processing and characterization of UHMWPE/α-tocopherol-CNTs nanocomposites

Durabilità dei film polimerici biodegradabili

Improved carbon nanotubes dispersion through polar dispersant agents in polyamide

The potential enhancement of the nanocomposite properties, with respect to the neat matrix, is strictly related to uniform distribution and dispersion of the nanofillers in the host polymer. In this work, two dispersant agents, particularly a polar wax and a silanol polyhedral oligomeric silsesquioxanes POSS, have been used in order to improve the dispersion of bare and functionalized carbon nanotubes in polyamide matrix. To ensure a good compatibility between matrix and nanofillers, the dispersing agents having specific polarity have been chosen, in order to match that of the matrix. Significant alterations of the mechanical and rheological behaviour due to dispersion action of used additi…

Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites

Polymer-based nanocomposites containing nanodiamonds (NDs) are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO) and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the …

A fractional-order model of ultra-high molecular weight polyethylene for biomedical implantation

On the interlayer spacing collaps of the Cloisite® 30B organoclay

Nitrogen-Doped Carbon Nanodots-Ionogels: Preparation, Characterization, and Radical Scavenging Activity

Hybrid diimidazolium-based ionogels were obtained by dispersing nitrogen-doped carbon nanodots (NCNDs) in ionic liquid (IL) solutions and by using dicationic organic salts as gelators. The properties of the NCND-ionogels were studied in terms of thermal stability, mechanical strength, morphology, rheological, and microscopic analyses. Insights into the formation of the hybrid soft material were attained from kinetics of sol-gel phase transition and from estimating the size of the aggregates, obtained from opacity and resonance light-scattering measurements. We demonstrate that, on one hand, NCNDs were able to favor the gel formation both in the presence of gelating and nongelating ILs. On t…

EFFECT OF ORGANOCLAY ON THE MORPHOLOGY AND MECHANICAL PROPERTIES OF POLYETHYLENE/POLYAMIDE BLENDS

POSS-poly(ethylene-co-acrylic acid) nanocomposites: physical interaction

Degradation and stabilization of the polyolefins and of the filled-polyolefins

Natural compounds as light stabilizers for biodegradable polymers

The role of different dispersing additives in the photo-oxidation behaviour of polyolefin-based OMMT nanocomposites

Preparazione e caratterizzazione di film poliolefinici nanocompositi per applicazioni in agricoltura

Photochemical stabilization of LLDPE/clay nanocomposites: towards durable nanocomposites

This article reports a study of the chemical modifications of LLDPE/nanoblend nanocomposites exposed to UV light in conditions of artificially accelerated ageing and natural weathering. Analysis by infrared spectroscopy of the chemical modifications produced by photoageing shows that the presence of an organo-clay leads to the decrease of the oxidation induction time of the polymer (LLDPE), which results in lower durability of the nanocomposites. Protection against photooxidation was tested with different kinds of UV stabilizers and with a metal deactivator. It is shown that the metal deactivator is very efficient in stabilizing the nanocomposite since it totally cancels the prodegradant ef…

Nano-hybrids based on quercetin and carbon nanotubes with excellent anti-oxidant activity

Abstract Multi-functional nano-hybrids based on Quercetin (Q), a natural antioxidant, and functionalized Carbon Nanotubes (CNTs) have been formulated and used to prepare Ultra High Molecular Weight PolyEthylene (UHMWPE)-based nanocomposites. The study of the nanocomposites rheological behaviour shows that the immobilization of Q molecules onto CNTs outer surface leads to a beneficial effect on the state of the interface between polymer and nanoparticles. Additionally, the investigation of the thermo- and photo-oxidation processes reveals that the hybrids nanoparticles are able to exert a remarkable stabilizing action, due to strong physical interaction between Q and CNTs. In particular, the…

Lavorazione e caratterizzazioni di film twist nanocompositi

Photooxidation and durability of PE based nanocopomsites

Materiali Compositi a Base di Polipropilene e Cariche Organiche Naturali: Proprietà e Applicazioni

Functionalized poly(butylene succinate) by nitroxide radical coupling

In recent years there has been a growing interest in developing sustainable alternatives to oil-based plastics. In particular, biodegradable aliphatic polyesters, such as poly(lactic acid) (PLA) and poly(butylene succinate) (PBS), are becoming increasingly important due to their valuable properties including thermoplastic processability and thermo-mechanical properties. Nonetheless, these materials present several drawbacks, such as the lack of reactive functionalities that are limiting their applications, versatility and successful use as commodity plastics. In this work it was investigated for the first time a new method of preparation of functionalized PBS by a post-polymerization approa…

The role of the matrix-filler affinity on morphology and properties of polyethylene/clay and polyethylene/ compatibilizer/clay nanocomposites drawn fibers

In this work the structural variations and mechanical performance of polyethylene/clay nanocomposite drawn fibres, also in the presence ofcompatibilizer, such as a commercial maleic anhydride grafted polyethylene, PEgMA, was studied. In the isotropic state both systems show intercalated morphology.After spinning and cold drawing, by adding the nanoparticles, the tensile strength as a function of the draw ratio increases and this rise is more pronounced for the filled compatibilized system. The reduction of the elongation at break, on the contrary, is about the same for all the examined samples. The orientation of the macromolecules, evaluated by measurements of the birefringence and calorim…

Rheological behaviour of ultrahigh molecular weight polyethylene/functionalized-MWCNTs nanocomposites

Natural anti-oxidants immobilized onto carbon nanotubes for thermo-oxidation resistant polymer-based nanocomposites

Morphology Modification of Polyethylene/Clay Nanocomposite Samples under Convergent Flow

The morphology of PE/CL nanocomposite samples subjected to convergent flows is studied. Elongational flow – the typical flow involved in spinning and film-blowing processing operations – significantly increases with the reduction of the capillary diameter. The values of the convergent extensional stress (calculated by Cogswell's formula) for the PE/CL systems, for all the adopted capillary geometries, are greater than the calculated values for pure polyethylene. The applied convergent flow, at the entrance of the capillary, is able to change the clay morphology and consequently the final material properties on the PE/CL system with limited affinity between the matrix and organo-modified cla…

Improvement of oxidation resistance of polymer-based nanocomposites through sonication of carbonaceous nanoparticles

Abstract The work aim is focused on two different aspects: first, the investigation of the effect of extended ultra-sound-assisted treatment (us) of carbonaceous nanoparticles, such as carbon nanotubes (CNTs) and carbon black (CB), on their radical scavenging activity, and second, the investigation of the oxidative resistance of polymer-based nanocomposites, containing us-treated CNTs and CB. Particularly, the CNTs and CB have been subjected to us sonication for different time intervals and the performed analysis reveals that both kinds of nanoparticles show decreased average hydrodynamic diameters and large content of surface defects. Really, the increased content of CNTs and CB defects, a…

Polyamide-Based Fibers Containing Microwave-Exfoliated Graphite Nanoplatelets

Exfoliated Graphite NanoPlatelets (GNP) have been obtained from Graphite Intercalation Compounds (GIC) subjected to thermal and microwave treatments. Accurate morphological and structural characterization of obtained GNP, performed to compare the degree of exfoliation, show that microwave-treated GNP, exhibit well-exfoliated structure, without any reduction in dimensions compared with the native GIC, differently to the thermal-treated ones. Microwave-treated GNP have been introduced in polyamide (PA) through melt-mixing to obtain nanocomposite that has been subjected to elongational flow, with the aim to improve the nanofiller dispersion and induce GNP orientation along the fiber direction.…

Thermo-oxidative stabilization of poly(lactic acid)-based nanocomposites through the incorporation of clay with in-built antioxidant activity

In this work, an innovative approach to overcome the issue of the poor thermo-oxidative stability of polymer/clay nanocomposites is proposed. Specifically, biodegradable poly(lactic acid) (PLA)-based nanocomposites, containing organo-modified clay with in-built antioxidant activity, were prepared. Through a two-step chemical protocol, a hindered phenol antioxidant was chemically linked to the ammonium quaternary salt which was then intercalated between the clay platelets [(AO)OM-Mt]. The nanocomposites were characterized and their thermo-oxidative stability during melt processing and under long-term thermal test conditions was investigated. PLA nanocomposites containing the (AO)OM-Mt showed…

Control of end-of-life oxygen-containing groups accumulation in biopolyesters through introduction of crosslinked polysaccharide particles

The formulation of bio-based materials with good performance in service and controlled end-of-life is imperative for an effective circular economy. In this work, an innovative approach to induce and control the end-of-life of biodegradable polyesters through introduction of crosslinked polysaccharide particles is proposed. Chitosan (Ch) has been subjected to ionotropically crosslinking and then added to polylactic acid (PLA) at different amounts (1.0–4.0%w) by melt mixing. All obtained results suggest that the addition of crosslinked Ch (cCh) particles does not modify significantly the investigated biopolyester properties. Specifically, the thermal analysis of the composites reveals that th…

Photo-Re-Stabilization of Recycled Post-Consumer Films for Greenhouses

Advanced nanofillers for polymers: antioxidants immobilized in layered clays

Rheology of poly(ethylene)-based nanocomposite films for agricultural applications

On the use of natural organic materials as fillers for recycled post-consumer plastices

Effect of C18 amine modifiers on the properties of LDPE-Montmorillonite nanocomposites

Biopolyester-based systems containing naturally occurring compounds with enhanced thermooxidative stability

Background This work presents a sustainable approach for the stabilization of polylactic acid (PLA) against thermo-oxidative aging. Methods Naturally occurring phenolic and polyphenolic compounds, such as ferulic acid (FerAc), vanillic acid (VanAc), quercetin (Querc) and vitamin E (VitE), were introduced into PLA. Results The preliminary characterization of the systems formulated containing different amounts of natural stabilizers showed that all compounds used acted as plasticizers, leading to a decrease in rheological functions with respect to neat PLA, without significantly modifying the crystallinity of the raw material. The study of the thermo-oxidative behavior of neat PLA and PLA/nat…

Preparation of functionalized-MW-CNTs/Polyolefin nanocomposites and analysis of their physical properties

Compositi Verdi: Miscele Post-Consumo Polietilene/Polipropilene con Fibre di Legno

Double bond-functionalized POSS: dispersion and crosslinking in polyethylene-based hybrid obtained by reactive processing

Polyethylene-based organic inorganic hybrids were prepared by one-step reactive melt mixing using a mono-functionalized nanofiller, i.e., allyl-heptaisobutyl-substituted polyhedral oligomeric silsesquioxane (1POSS) and a multi-functionalized octavinyl polyhedral oligomeric silsesquioxane (8POSS). The hybrids were also prepared in dicumyl peroxide (DCP) presence and morphological, spectroscopical and calorimetric analysis were carried out. Moreover, rheological measurement and Sohxlet extraction were performed on investigated samples. It was inferred that double bonds of POSS functional groups were triggered by radicals coming from the peroxide decomposition or from the degradation reactions…

Un nuovo strumento per misurare il comportamento al creep in condizioni reali di sistemi polimerici

Durability of multi-phase polymer based nanocomposites

Photo-Stability Improvement of Polystyrene-block-Polybutadiene-block-Polystyrene through Carbon Nanotubes

The photo-oxidation stability of Polystyrene-Polybutadiene-Polystyrene (SBS) based nanocomposites containing bare multi-walled carbon nanotubes (CNTs) and carbon nanotubes bearing hydroxyl functional groups (CNTs-OH) in comparison to that of pristine SBS has been widely investigated. The photo-oxidation of pristine SBS occurs through crosslinking reactions and oxidized species formation and both these processes begin at early stage of exposure. The formation of crosslinking, formerly in polybutadiene phase, assessed by spectroscopical (FTIR), mechanical, dynamic mechanical and rheological analysis, leads to occurrence of internal mechanical stresses in the solid state and the SBS samples be…

Nanocomposites based on polystyrene and POSS molecules: properties and photo-stability

Natural stabilization for bio-polymeric systems

Photo-re-stabilization of recycled post-consumer films from greenhouses

Accelerated weathering of PP based nanocomposites: Effect of the coupling agent

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Degradation of Polymer Clay-Nanocomposites: a Novel Approach to Enhancing Service Life Performance

The problem of degradation of polymer-clay nanocomposites was addressed by sdopting a novel clay-stabilisation methodology prior tothe incorporation of the clay for reinforcement

Nanocomposites based on UHMWPE and α-tocopherol-CNTs: processing and characterization

Compression and injection molding of recycled polyethylene for greenhouses in presence of the natural fibres

Understanding the physical and/or chemical interaction in POSS-poly(ethylene-co-acrylic acid) nanocomposites

Photo-oxidation behaviour and morphology of zinc oxide-poss polystyrene based nanocomposites

Progress in Understanding of the Interactions between Functionalized Polyolefins and Organo-Layered Double Hydroxides

The dispersion of organo-layered double hydroxides (O-LDH) in functionalized polyolefins (POs) is investigated. Two different polyethylene matrices (maleic anhydride (MAH) and diethyl maleate functionalized) are tested and a hydrogenated fatty acid modified LDH is used. The attention is focused on evidencing the interaction between the functional groups of the polymer and the O-LDH through FT-IR. Moreover, a combination of solvent fractionation, morphological, and rheological characterizations enables to gain a deeper insight into the structure of these composites. In particular, the formation of bridging bonds between the particles and MAH functionalized macromolecules is assumed, possibly…

Effect of different processing techniques and presence of antioxidant on the chitosan film performance

In the last two decades, the naturally occurring polysaccharides have gained great attention because of their potential applications in different sectors, for example, from food to biomedical sectors. Chitosan is a cationic polysaccharide with good transparency, and currently, it has been considered also as suitable material for the formulation film and coating in cultural heritage protection. In this work, the chitosan films (Ch), with and without natural antioxidant such as citric acid (CA), are formulated considering two different processing techniques: (i) conventional solvent casting and (ii) compression molding, that is an unconventional method for this polysaccharide, giving the poss…

Pluronic nanoparticles as anti-oxidant carriers for polymers

Abstract The immobilization of anti-oxidant stabilizers for polymers, particularly naturally occurring systems, can be considered a valuable route for preventing their migration, volatilization, thermo-degradation and decomposition at typical high processing temperatures, as well as for enhance their solubility in polymers. In this work, an innovative approach for the immobilization of naturally occurring stabilizer, through the encapsulation in copolymer nanoparticles, is proposed. Pluronic nanoparticles (PNPs), based on PEO-PPO-PEO, (PEO: poly (ethylene oxide); PPO: poly(propylene oxide)), without and with quercetin, Q, have been successfully formulated and the critical micellar condition…

Termo- e foto- degradazione di nano compositi a base di nylon 11

Negli ultimi anni la poliammide 11 (PA11) ha suscitato un notevole interesse in svariati settori industriali industriali.Per ottimizzare la comprensione dei meccanismi che governano la termo e foto ossidazione della PA11, sono stati studiati mediante Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) , cromatografia ad esclusione sterica (SEC) e viscosimetria, i processi di degradazione termo e foto-ossidativi che interessano il PA11 ed in particolare i nanocompositi formulati con Cloisite30B

Natural anti-oxidant additives for bio-degradable polymers

Concentration-dependent anti-/pro-oxidant activity of natural phenolic compounds in bio-polyesters

Abstract In this work, the potential of several naturally occurring phenolic compounds, such as Ferulic Acid (FA), Vanillic Acid (VA), Vitamin E (VE) and Quercetin (Q), as stabilizers against the photo-oxidative degradation of Polylactic acid (PLA) has been assessed. Specifically, PLA-based films containing different amounts of considered stabilizers have been formulated and their photo-stability under UVB exposure has been evaluated. The preliminary characterization of the formulated films shows that all used stabilizers exert plasticizing action, as probed by rheological analysis, due to their low molecular weight. Moreover, no significant modification of the PLA crystallinity has been no…

Recycling of RPE/ Ground Tire Rubber Blends: Properties and Applications

Re-gradation of Photo-oxidized Post-consumer Greenhouse Films

The degradation undergone by the polymers during their use and because of the thermo-mechanical degradation undergone during the reprocessing operations provokes, among other effects, the decrease of the molecular weight. The change of the molecular architecture is responsable for the deterioration of all the properties. In order to restore the properties of post-consumer recycled plastics, some rebuilding of the molecular structure is necessary. In this work, photo-oxidized films for greenhouses were reprocessed in presence of additives able to react with the polyethylene in order to form branching and cross-linking, improving the properties of these post-consumer plastic.

Effect of thermal cycles on the rheological behaviour of polymerclay nanocomposites

Il ruolo di molecole POSS(polyhedral oligomeric silsesquioxane) sulle relazioni proprietà struttura nei nanocompositi a base polistirenica

The antioxidant behavior of functional nitroxide grafted polyethylene samples

In this work, the thermo- and photo-oxidation stability of functional nitroxide grafted polyethylene (PE) samples was tested.

Effects of organoclay on morphology and properties of nanocomposites based on LDPE/PA-6 blends without and with SEBS-g-MA compatibilizer

LDPE/PA-6 blends (75/25 wt/wt) were added with SEBS-g-MA (S) and/or an organoclay (20A) using different compounding sequences and the morphology and the properties of the blends or composites were investigated. An XRD study of the nanocomposites with pure polymers showed that 20A is intercalated by LDPE or PA-6 chains, whereas it is exfoliated by S if the clay concentration does not exceed 10 wt%. The SEM investigation showed that both S and 20A behave as efficient emulsifying agents for the LDPE/PA-6 blends. However, their effect on the mechanical properties was found to be opposite: S enhanced toughness but lowered the stiffness, whereas 20A improved the elastic modulus but impaired the i…

Photo- and thermo- oxidative resistance of novel nanocomposites based on CNT-POSS hybrid nanofillers

Bionanocomposite films containing halloysite nanotubes and natural antioxidants with enhanced performance and durability as promising materials for cultural heritage protection

In the last decade, the interest toward the formulation of polymer films for cultural heritage protection continuously grew, and these films must be imperatively transparent, removable, and should not react/interact with surface of the artworks. In this research, bionanocomposite films, based on chitosan (Ch) and pectin (P) and containing naturally occurring fillers and antioxidants, were formulated by solvent casting methods and were accurately characterized. The natural halloysite nanotubes (HNT) have a two-fold role, specifically, physical compatibilizer and antioxidant carrier. Therefore, the theoretical solubility between Ch and P was estimated considering Hoy&rsquo

The role of filler type in the photo-oxidation behaviour of micro- and nano-filled polypropylene

The rising interest in polymer nanocomposites leads also to an increasing concern for their photo-oxidation resistance. The main properties and photo-oxidation behaviour of polypropylene-based microcomposites and nanocomposites were investigated. The results show that the use of nanosized calcium carbonate may lead to a higher photo-oxidation rate than that of pristine polypropylene, in a way that is comparable to organo-modified nanoclays. It is also observed that nanosized calcium carbonate causes higher photodegradation rates than microsized calcium carbonate. The main reasons for the increased photo-oxidation rates when using organo-modified nanoclays include the presence of iron ions, …

Effect of thermal treatment time on the rheological behaviour of PE based nanocomposites

On the interlayer spacing collapse of Cloisite (R) 30B organoclay

Abstract When used as a nanofiller for the preparation of polymer/clay nanocomposites (PCNs), Cloisite® 30B (30B) often undergoes a d-spacing collapse, as demonstrated by a shift to wider angles of the XRD basal reflection. Such collapse has been variously attributed to organoclay contamination or, more often, to thermal degradation of the organic modifier with expulsion of the volatile products from the galleries. In this work, several PCNs loaded with 30B have been prepared by melt compounding, using different polymer matrices, and have subsequently been subjected to dissolution in appropriate solvents followed by precipitation in excess non-solvent and room temperature drying. An XRD ana…

Invecchiamento naturale e durabilità dei materiali polimerici

Environmentally Friendly Eutectogels Comprising l-amino Acids and Deep Eutectic Solvents: Efficient Materials for Wastewater Treatment.

Current concerns for sustainability and the environment make low-impact materials desirable for environmental remediation and, in particular wastewater treatment. We obtained supramolecular gels of l-amino acids in the deep eutectic solvent formed by choline chloride and phenylacetic acid. After gel characterization, and investigating gel-sol transition temperatures, gelation kinetics, rheological properties, and morphology, the gels were applied as sorbents to remove cationic dyes from aqueous solutions. The effects of the pH, dye nature, volume, and concentration of wastewater were analyzed, and the best result was obtained with a l-phenylalanine-based eutectogel. It can be reused for at …

The role of the clay in morphology modification of the uncompatible polymer blends

Role of organo-modifier and metal impurities of commercial nanoclays in the photo-and thermo-oxidation of polyamide 11 nanocomposites

The photo-oxidative degradation processes of bio-based PA11 nanocomposites containing montmorillonite (MMT) and the organo-modified Cloisite&reg

Effect of the elongational flow on the morphology and on the properties of polyethylene based nanocomposites

Role of oxygen on rheological response of polyethylene–clay nanocomposites to annealing

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Thermoset materials and their composites are characterized by a long life cycle with their main applications in aircrafts, wind turbines and constructions as insulating materials. Considering the importance of recovery and valorization of these materials at their end-of-life, avoiding landfilling, the interest concerning their recycling grows continuously. The thermoset materials and their composites, to be successfully recovered and valorized, must degrade their three-dimensional structures and recover the mono-oligomers and/or fillers. The thermoset materials could successfully degrade through thermal treatment at different temperatures (for example, above 1000 °C for incineration, ca. 50…

Photo-oxidation of polyolefin/clay nanocomposite films: role of organoclay and matrix type

An insight into the interaction between functionalized thermoplastic elastomer and layered double hydroxides through rheological investigations

Abstract Nanocomposites based on maleated poly(styrene-(ethylene-co-butylene)-styrene) copolymer (SEBSgMA) and organo-modified layered double hydroxide (OLDH) have been formulated with the aim to investigate the effects of interfacial interactions between the grafted maleic anhydride groups of the copolymer and the OLDH nanolayers on the rheological properties of nanocomposites. The spectroscopic analysis indicates the establishment of specific polymer/nanofiller interactions, whose extent has been highlighted through morphological and rheological investigations. Specifically, oscillatory melt rheology and shear relaxation tests have been considered in order to deeply investigate the interf…

Grafting of polymer chains on the surface of carbon nanotubes via nitroxide radical coupling reaction

Poly(butylene succinate) (PBS) was grafted on the surface of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) modified multi-walled carbon nanotubes (MWCNTs) via a nitroxide radical coupling reaction. TEMPO functionalized MWCNTs (MWCNTs-g-TEMPO) were synthesized using the Cu(I)-catalyzed azide/alkyne click chemistry approach and the covalent bond of the nitroxide moieties onto the MWCNTs was confirmed via electron paramagnetic resonance (EPR) spectroscopy. The PBS grafting on the sidewalls of MWCNTs was carried out in solution via peroxide-induced formation of macroradicals and it was confirmed by EPR and attenuated total reflectance Fourier transform infrared analysis. Preliminary rheological …

Ecofriendly Biopolymer-Based Nanocomposite Films with Improved Photo-Oxidative Resistance

The interest towards high performance biopolymer-based materials increases continuously and, to guarantee appropriately industrial applications, the photo-oxidative resistance and stability of these materials must be adequately addressed. In this study, innovative biopolymer-based nanocomposites, i.e., Polyamide 11 (PA11), containing ad-hoc modified Layered Double Hydroxides (LDH), were successfully formulated and characterized. Particularly, LDH were considered carriers for hindered amine light stabilizing molecules, so two different hindered amine moieties (HALS1 and HALS2) were anchored on LDH layered internal structures and/or outer surfaces. The presence of HALS1 and HALS2 in LDH were …

High-performance thermoplastic elastomers/carbon nanotubes nanocomposites: Mechanical behavior, rheology, and durability

Advanced polystyrene-b-polybutadiene-b-polystyrene (SBS) based nanocomposites containing bare carbon nanotubes (CNTs) and CNTs bearing hydroxyl functional groups (CNTs-OH) have been formulated and fully characterized. In particular, the reinforcement effect of CNTs and CNTs-OH on SBS was deeply investigated through mechanical and dynamical thermo-mechanical analysis and the rheological response of SBS-based nanocomposites was investigated and discussed. The mechanical properties of SBS/CNTs and even more of SBS/CNTs-OH nanocomposites are substantially superior to those of neat SBS, due to the uniformly dispersed nanofillers throughout the polymeric matrix. The presence of -OH groups onto CN…

Processability and Properties of Re-Graded, Photo-Oxidized Post-Consumer Greenhouse Films

The recycling of post‐consumer plastics leads, in general, to secondary materials having properties worse than those of the reclaimed material and certainly worse than those of the same virgin polymer. This is because of the degradation undergone by the objects during their use and because of the thermo‐mechanical degradation undergone during the reprocessing operations. The change of the molecular architecture is responsible for this worsening of properties. The use of stabilizing systems can slow the degradation during the melt processing but cannot give any improvement of the final properties of the material. In order to enhance the properties of the recycled plastics, some rebuilding of…

Nanocompositi a base polimerica e molecole POSS: comportamento reologico e proprietà fisiche

Nanocomposites based on PS, PE, or ethylene-acrylic acid (ESCOR 5001) and POSS (Polyhedral oligomeric SilseSquioxanes) molecules were prepared by melt mixing. The nanocomposites’s structure-property relationships were analyzed mainly by rheological investigations and the variations with respect to the matrices were highlighted. The results of the rheological analysis show that the POSS molecules affect the properties in the molten state and act as plasticizer that is contrasted by the hydrogen bonds. The inorganic cage’s structure and the organic nature of the vertex groups of the molecules POSS play an important role in modulating the dispersion and in determining the final properties of t…

Polyamide/carbonaceous particles nanocomposites fibers: Morphology and performances

In this work, the influence of carbonaceous particles with different sizes and shapes on the morphology and mechanical performances of polyamide (PA)-based fibers was investigated. Graphene nanoplatelets (GNP) are compared with spherical and rod-like carbon fillers such as carbon black (CB) and multiwall carbon nanotubes (CNTs). The increments of the complex viscosity as well as elastic and loss moduli, in the melt state, assessed by rheological analysis, are reduced by modifying polyamide (PA) matrix with nanofillers in a following order: CNTs > GNP > CB. All the nanocomposites, however, show viscosity and moduli higher than those of neat PA. The CB loading causes a mere increase of the vi…

Diimidazolium-based supramolecular ionogels for dye removal from wastewaters

Degradation of PA 11 nanocomposites: the chemical point of view

We aim to investigate both thermal degradation processes (non oxidative and oxidative) occurring in PA11 nanocomposites and establish the eventual contribution of organo nanoclay modifier on degradation mechanisms.

Formulation of Agricultural Films by Using of the Recycled Polymers: Resistance to the Photoxidation

preparazione e caratterizzazione di nanocompositi polimero/CNTs sottoposti a stiro elongazionale

Lo scopo principale di questo lavoro è rivolto alla preparazione di sistemi polimero/CNTs (in particolare a 1 e 3 % in peso di CNTs) e alla caratterizzazione reologica e meccanica dei filamenti in funzione del rapporto di stiro.

Performances and morphology of polyamide/carbonaceous structures based fibers

In this work the influence of carbonaceous particles with different particle sizes and shapes on the morphology and mechanical performances of polyamide (PA) based fibers was investigated. Graphene nanoplatelets (GNP) are compared with spherical and rod-like carbon fillers such as carbon black (CB) and multiwall carbon nanotubes (MWCNT). The different morphologies of the particles control their dispersion and their alignment in PA fibers upon elongational flow action and play a key role in structure-property relationships.

Micro- and Nano- polymer based composites for novel generation bio-medical materials

Compression and injection molding of recycled polyethylene for greenhouses in presence of the natural fibers

Green Composites a base di materie plastiche post-consumo e cariche organiche naturali

On the use of natural organic materials as fillers for recycled post-consumer plastics

Functionalization of aliphatic polyesters by nitroxide radical coupling

Functionalized poly(butylene succinate) (PBS) samples were prepared by a post-polymerization method based on the coupling reaction between TEMPO derivatives bearing different functionalities and PBS macroradicals generated by H-abstraction using a peroxide. 4-Benzoyloxy-2,2,6,6-tetramethylpiperidine-1- oxyl (BzO-TEMPO) and 4-(1-naphthoate)-2,2,6,6-tetramethylpiperidine-1-oxyl (NfO-TEMPO), a pro-fluorescent nitroxide, were successfully grafted on PBS, as revealed by MALDI TOF MS and UV-Vis spectroscopy. The functionalization degrees were accurately determined by UV-Vis analysis and confirmed by 1H-NMR spectroscopy. The grafting site was identified by combining theoretical calculations with e…

UNEVEN DISTRIBUTION OF ORGANOCLAY IN HDPE/PA6 BLENDS - IMPACT OF MICROSTRUCTURE AND MECHANICAL BEHAVIOUR

High performance composites containing perfluoropolyethers-functionalized carbon-based nanoparticles: Rheological behavior and wettability

Abstract Ultra High Molecular Weight Polyethylene (UHMWPE) based composites filled with carbon nanotubes (CNTs) and carbon black (CB) modified by perfluoropolyethers (PFPE) have been formulated. All composites show a segregated morphology with nanofillers selectively localized at the polymer particle–particle interface. The composites rheological properties have been deeply investigated: the PFPE functionalities linked on CNTs facilitate the semi-3D nanofillers network formation in the composites that show a solid-like behaviour even at lower investigated filler contents, reaching the rheological percolation threshold at lower nanofiller content than bare CNTs filled composites. For composi…

Morphology and properties of LDPE/PA-6 blends compatibilized with SEBS-g-MA and/or organoclay

Effects of a new multifunctional additive on the thermo-stability, photo-stability and on the processability of the polyamide 6

Mechanical and rheological properties of polystyrene-block-polybutadiene-block-polystyrene copolymer reinforced with carbon nanotubes: effect of processing conditions

Abstract Styrene-b-butadiene-b-styrene (SBS)-based nanocomposites filled with unmodified and –COOH functionalized carbon nanotubes (CNTs) have been formulated at different processing conditions in order to provide an understanding of the influence of the processing temperature and mixing speed on the nanofillers dispersion and on the overall properties of the nanocomposites. The evaluation of the nanocomposites’ mechanical and rheological behavior reveals that the effect of the processing speed on the final properties is almost negligible. Differently, the processing temperature influences strongly the mechanical and rheological properties of SBS-based nanocomposites. Indeed, for the nanoco…

Properties of recycled polyethylene/organic fillers green composites

Influenza di argille organomodificate su morfologia e proprietà di miscele polimeriche polietilene/poliammide

The role of POSS on the structure-properties relationship in Polystyrene based nanocomposites

Interaction in POSS-poly(ethylene-co-acrylic acid) nanocomposites

Use of polyhedral oligomeric silsesquioxane (POSS) in polymer-based nanocomposites is promising for the design of high-performance materials for several applications. In this study, nanocomposites based on ethylene-acrylic acid (EAA) copolymer and POSS molecules were prepared by melt mixing. In particular, partial cage POSS with different pendent organic groups was used to investigate the interaction between the –OH groups of POSS and the acrylic functionalities of the matrix. All nanocomposites were characterized by mechanical, rheological, thermal and spectroscopic analyses. In addition, PE-POSS compounds were prepared under the same processing conditions for sake of comparison. The POSS …

Influenza del flusso convergente in sistemi nanocompositi a matrice polietilenica

Advanced ultra-high molecular weight polyethylene/antioxidant-functionalized carbon nanotubes nanocomposites with improved thermo-oxidative resistance

Multiwalled carbon nanotubes (CNTs) functionalized with hindered phenol moieties are dispersed in ultra-high molecular weight polyethylene (UHMWPE), and the stabilizing action of the antioxidant (AO) functionalized CNTs (AO-f-CNTs) is studied through a combination of rheological and spectroscopic (FT-IR) analyses. The effectiveness of two alternative compounding methods, namely hot compaction (HC) and melt mixing (MM), is compared. The combination of high temperature and mechanical stress experienced during MM brings about noticeable degradation phenomena of the matrix already in the course of the compounding step. Differently, the milder conditions of the HC process preserve the stability …

Polyethylene/clay nanocomposites with or without compatibilizer: effect of extensional flow

Effect of different matrices and nanofillers on the rheological behavior of polymer-clay nanocomposites

In this work, a comprehensive study of the rheological behavior under shear and isothermal and nonisothermal elongational flow of low density polyethylene (LDPE) and ethylene-vinyl acetate copolymer (EVA) based nanocomposites was reported to evaluate their "filmability", that is, the ability of these material to be processed for film forming applications. The influence of two different kinds of organoclay - namely Cloisite 15A and Cloisite 30B - and their concentration was evaluated. The presence of filler clearly affects the rheological behavior in oscillatory state of polyolefin-based nanocomposites but the increase of complex viscosity and the shear thinning are not dramatic. A larger st…

Hybrid supramolecular gels of Fmoc-F/halloysite nanotubes: Systems for sustained release of camptothecin

Supramolecular gel hybrids obtained by self-assembly of Fmoc-L-phenylalanine (Fmoc-F) in the presence of functionalized halloysite nanotubes (f-HNT) were obtained in biocompatible solvents and employed as carriers for the delivery of camptothecin (CPT) molecules. The synthesis of the new f-HNT material as well as its characterization are described. The properties of the hybrid hydrogels and organogels were analyzed by several techniques. The presence of small amounts of f-HNT allows good dispersion of the tubes and the subsequent formation of homogeneous gels. The experimental results show that f-HNT functions only as an additive in the hybrid gels and does not demonstrate gelator behavior.…

Effect of Short-Term and UV Irradiation Aging on the Behaviour of SBS-Modified Bitumen

To obtain road bitumen with improved temperature and fatigue resistance, polymers and/or rubbers could be added to it. A particularly suitable polymer for bitumen modification is styrene-butadiene-styrene (SBS) copolymer but limited information is available about the ageing behaviour of modified binders. In this work, two neat bitumens, with different penetration grades, and two SBS-modified bitumens, containing different SBS amounts, were selected, and their short-term and UVB ageing behaviour were investigated considering dynamic shear rheometry and Attenuated Total Reflectance-Fourier Transformation InfraRed spectroscopy (ATR-FTIR). Short-time ageing behaviour was investigated performing…

Biopolyester-based systems containing naturally occurring compounds suitable for biomedical devices

Slow Pyrolysis as a Method for Biochar Production from Carob Waste: Process Investigation and Products’ Characterization

The zero-waste city challenge of the modern society is inevitably addressed to the development of model’s waste-to-energy. In this work, carob waste, largely used in the agro-industrial sector for sugar extraction or locust beangum (LBG) production, is considered as feedstock for the slow pyrolysis process. According to the Food and Agriculture Organization of the United Nations (FAO), in 2012, the world production of carobs was ca. 160,000 tons, mainly concentrated in the Mediterranean area (Spain, Italy, Morocco, Portugal, and Greece). To evaluate the biomass composition, at first, the carob waste was subjected to thermo-gravimetric analysis. The high content of fixed carbon suggest…

Anti-/Pro-Oxidant Behavior of Naturally Occurring Molecules in Polymers and Biopolymers: A Brief Review

Polymers and biopolymers are continuously subjected to the action of different stress factors, such as oxygen, heat, UV light, mechanical stress, humidity, etc., during their processing and service life, undergoing overall oxidative degradation, that causes performance and property deterioration. To improve the resistance at high temperatures and long-term weatherability of the polymers and biopolymers, usually, during their manufacturing, synthetic antioxidants and UV-light stabilizers are added. In the past decade, several concerns related to the impact of the synthetic stabilizers have emerged, and to reduce their negative effect on human health and the environment, their replacement wit…

Organoclay Nanocomposites from Ethylene-Acrylic Acid Copolymers

A study of the structure–property relationships for nanocomposites prepared by melt compounding from ethylene–acrylic acid copolymers of varied composition and molecular architecture, and organoclays modified with different ammonium ions has been made by DSC, POM, SEM, TEM, WAXD, and rheological and mechanical tests. Within the series of clays investigated, the best levels of dispersion were displayed by those organically modified with quaternary ammonium ions containing two long alkyl tails. The relevant nanocomposites were shown to possess mixed exfoliated and intercalated morphology. The spacing of the intercalated clay stacks, most of which comprise few silicate layers, was found to be …

Recycling ground tire rubber (GTR) scraps as high-impact filler of in-situ produced polyketone matrix

Anti-ossidanti naturali per polimeri biodegradabili

Effetto del flusso elongazionale sulle proprietà e sulla morfologia di filamenti di nanocomposito a base di polietilene e montmorillonite organo-modificata

LDPE/EVA/Clay nanocomposites: prcessability and properties

INTERACTIONS BETWEEN FUNCTIONALIZED THERMOPLASTIC ELASTOMER AND LAYERED DOUBLE HYDROXIDES

Results coming from rheological analysis clearly suggest that in SEBS-g-MA-based nanocomposites, containing high amount of o-LDH, the formation of strong interactions between the dispersed nanoparticles and maleic functionalities of matrix occurs. A significant modification of the rheological behaviour can be noticed due to the formation of gel-like structures.

Intercalation effects in LDPE/o-Montmorillonites nanocomposites

Abstract Typical montmorillonite clays (Cloisite ® Na + , Cloisite ® 30B) were modified by treatment with octadecyl ammonium chloride (ODC) and successive additions of octadecylamine (ODA). XRD analyses of the modified clays indicated an increase of the basal spacing of the (0 0 1) planes depending on the ODC or ODA additions. Nanocomposites were prepared by dispersing the modified clays (3% w/w concentration) in LDPE, using a Brabender mixer. XRD measurements of the obtained products indicated in some cases the achievement of intercalation effects, which were confirmed by TEM analysis. Some thermal, mechanical, dynamic-mechanical and rheological properties were evaluated and correlated to …

On the role of extensional flow in morphology and property modifications of MWCNT/polyamide-based fibres

Unfilled and MWCNT-filled PA fibers are prepared and the effect of the extensional flow on their mechanical performance and morphological variations is investigated. Morphological analyses using SEM, TEM, and SAXS suggest a stronger orientation of the MWCNTs along the fiber direction with increasing extensional flow. A particular MWCNT bundle formation in the PA drawn nanocomposite fibers is observed for the first time, and a pull-out of the central nanotube in some bundles is noted. The maintenance of the “shish-kebab” structure upon extensional flow is responsible for the mechanical improvements and dimensional stability in MWCNT-filled PA fibers.

Photo-oxidation of nano- and micro-filled polypropylene

Nanocompositi ad elevata resistenza termo-ossidativa a base di poliammide e nano-argille multifunzionali

One-step reactive processing of low density polyethylene and octavinyl polyhedral oligomeric silsesquioxane

Polyhedral oligomeric silsesquioxane (POSS) are an innovative class of organosilicon compounds suitable for formulation of advanced organic-inorganic hybrid materials. Nanocomposites based POSS found application mostly in high-temperature resistance and fire-resistance materials. POSS are characterized by a three dimensional cage-like structure, made of Si-O bonds, with different organic groups directly linked to the Si atoms of the cage structure. The organic groups can be designed to facilitate the dispersion of the nanoparticle itself in the polymer matrix or also to react with the polymer chain. This work focuses on the possibility to obtain crosslinking of polyethylene using octavinyl-…

Improvement of the photo-stability of polystyrene-block-polybutadiene-block-polystyrene through carbon nanotubes

Abstract The photo-stability of Polystyrene-Polybutadiene-Polystyrene (SBS) based nanocomposites containing bare multi-walled carbon nanotubes (CNTs) and carbon nanotubes bearing carboxylic functional groups (CNTs-COOH) in comparison to that of pristine SBS has been studied. The photo-oxidation of pristine SBS occurs through crosslinking reactions and oxidized species formation and both these processes begin at early stage of exposure. The formation of crosslinking, formerly in polybutadiene phase, assessed by spectroscopical (FTIR), mechanical, dynamic mechanical and rheological analysis, leads to occurrence of internal mechanical stresses in the solid state and the SBS samples become prem…

Effect of Different Matrices and Nanofillers on the Rheological Behavior of Polymer-Clay Nanocomposites

In this work, a comprehensive study of the rheologi-cal behavior under shear and isothermal and nonisothermal elongational flow of low density polyethylene (LDPE) and ethylene-vinyl acetate copolymer (EVA) based nanocomposites was reported to evaluate their "filmability", that is, the ability of these material to be processed for film forming applications. The influence of two different kinds of organoclay - namely Cloisite 15A and Cloisite 30B - and their concentration was evaluated. The presence of filler clearly affects the rheological behavior in oscil-latory state of polyolefin-based nanocomposites but the increase of complex viscosity and the shear thinning are not dramatic. A larger …

Properties and morphology of PA based filament loaded with MW-CNTs: effect of filler aspect ratio and surface functionalization

Natural Compounds as Sustainable Additives for Biopolymers

In the last few decades, the interest towards natural compounds, coming from a natural source and biodegradable, for biopolymers is always increasing because of a public request for the formulation of safe, eco-friendly, and sustainable materials. The main classes of natural compounds for biopolymers are: (i) naturally occurring fillers (nFil), such as nano-/micro- sized layered alumino-silicate: halloysite, bentonite, montmorillonite, hydroxyapatite, calcium carbonate, etc.; (ii) naturally occurring fibers (nFib), such as wood and vegetable fibers; (iii) naturally occurring antioxidant molecules (nAO), such as phenols, polyphenols, vitamins, and carotenoids. However, in this short review, …

Photooxidation and Durability of PE Based Nanocomposites

Degradazione termomeccanica di nanocompositi a base poliolefinica

Ruolo della reologia nel fenomeno della co-continuità indotta da nanoparticelle in blend polimerici immiscibili

Ruolo della reologia nelle evoluzioni morfologiche di miscele polimeriche immiscibili nano composite

Effect of nano zinc oxide as UV stabilizer on the weathering performance of wood-polyethylene composite

Abstract In this study, the effect of using nano-sized zinc oxide (ZnO) particles on the enhancement if the degradation resistance of wood-high density polyethylene (HDPE) composite was investigated through artificial weathering. Samples with different amounts of ZnO mixing ratio (0, 1, 2, and 4 wt%) were manufactured using an internal mixer followed by compression molding. The prepared samples were then exposed to the artificial weathering process in a QUV weatherometer. The weathering behavior of samples was characterized using tensile strength, contact angle analysis, colorimetry, ATR-FTIR spectroscopy and FE-SEM. The results indicated that the amount of surfaces crack, tensile strength …

Mechanical and rheological analyses of recycled polyethylene and ground tyre rubber

Novel strategic approach for the thermo- and photo- oxidative stabilization of polyolefin/clay nanocomposites

Polyolefin/clay nanocomposites were prepared by melt mixing and their oxidative stability was studied under long-term thermo- and photo-oxidative test conditions in the absence and presence of a modified organo montmorillonite clay (OM-MMt) containing a chemically-bound hindered phenol antioxidant function, (AO)OM-Mt. It was found that nanocomposites based on both polyethylene (PE) and polyethylene-grafted-maleic anhydride (PEgMA) containing the (AO)OM-Mt gave a higher oxidative stability, along with better clay dispersion, compared to analogous PE or PEgMA-based nanocomposites containing an added (free) conventional antioxidant with a similar hindered phenol function (using the commercial …

How the POSS molecules improve the UV stability of polystyrene based nanocomposites?

MODIFICAZIONI COVALENTI DI NANOTUBI DI ALLOSITE PER APPLICAZIONE NEL DRUG DELIVERY

Nell'ampio scenario dei nanomateriali, i sistemi nanotubolari godono di un consolidato e crescente interesse sia nell'ambito scientifico che industriale. Fra la miriade di sistemi tubolari, recentemente i nanotubi allosite (HNT) hanno attirato l’attenzione della comunità scientifica.1 Grazie alla presenza di una cavità vuota, gli HNT trovano, principalmente, applicazione come nanocontainer per il rilascio controllato di composti chimici, in particolare, farmaci. L’introduzione di modificazioni covalenti su entrambe le superfici permette di modulare le proprietà dell’allosite, aumentando così i suoi campi di applicazione. In questa comunicazione verranno presentati recenti risultati ottenuti…

A Fractional-Order Model of Biopolyester Containing Naturally Occurring Compounds for Soil Stabilization

Currently, the use of polymers and biopolymers as soil-stabilizer additives for control of the soil degradation, deterioration, and desertification and for improving the arid and semiarid soils has been expanded significantly in the agricultural sector. This research was conducted to determine the effect of naturally occurring compounds, such as quercetin (Q) and sodium montmorillonite (NaMMt) at different weight ratios, in biopolyester, such as polylactic acid (PLA), aiming to formulate ecosustainable materials to control the soil degradation and to protect the environment. As known, the use of sophisticated analytical tools to describe the material rheology and melting properties is nowad…

Ionic liquids gels: Soft materials for environmental remediation

Abstract Hypothesis Nanostructured sorbents and, in particular, supramolecular gels are emerging as efficient materials for the removal of toxic contaminants from water, like industrial dyes. It is also known that ionic liquids can dissolve significant amounts of dyes. Consequently, supramolecular ionic liquids gels could be highly efficient sorbents for dyes removal. This would also contribute to overcome the drawbacks associated with dye removal by liquid–liquid extraction with neat ionic liquids which would require large volumes of extractant and a more difficult separation of the phases. Experiments Herein we employed novel supramolecular ionic liquid gels based on diimidazolium salts b…

Morphology and properties of polyolefin/clay nanocomposites drawn fibers

Multi-functional hybrid-carbon nanotubes for advanced Ultra-High Molecular Weight Polyethylene-based nanocomposites: a novel approach for stabilization

Our results demonstrate that immobilizing stabilizing molecules on nanoparticles, and using the latter as multifunctional filler for nanocomposites, is a viable route towards to produce high-performance polymeric materials

Rheological Response of Polyethylene/Clay Nanocomposites to Annealing Treatment

The rheological response of a polyethylene/clay nanocomposite to annealing treatment under air and nitrogen atmospheres was studied. The treatment influences the rheology of the nanocomposite significantly. In particular, the viscosity and the non-Newtonian behavior dramatically increase with annealing time, and a liquid-like/solid-like transition is observed. The annealed samples were characterized by ATR-FT-IR spectrometry and it was shown that a silicate-rich layer is formed on the surface of the nanocomposite. This result was confirmed by TEM images of bulk and surface of annealed samples. It was demonstrated that the formation of this coating is the main cause of the change of rheologi…

Morphology of Polyamide/Polyethylene Blends in Presence of Nanoclay

Utilizzo di materiali riciclati per la produzione di film agricoli per copertura: resistenza alla foto-ossidazione

Polymer based nanocomposites for novel generation greener material

Effect of annealing under different atmospheres on polyethylene-clay nanocomposites

Carbon Nanomaterial Doped Ionic Liquid Gels for the Removal of Pharmaceutically Active Compounds from Water.

Due to large drug consumption, pharmaceutically active compounds (PhACs) can be found as water contaminants. The removal of PhACs is a significant issue, as they can easily overtake traditional purification methods. Because of their surface properties, carbon nanomaterials are among the most efficient materials able to adsorb PhACs. However, their limitation is their recovery after use and their possible leakage into the aquatic system. Consequently, new hybrid supramolecular ionic liquid gels (HILGs) have been designed for the adsorption of some antibiotic drugs (ciprofloxacin and nalidixic acid) from water. The chemical&ndash

Effect of the processing on polyethylene/clay nanocomposites

Photo-degradation behaviour of OMMT-filled PE/PA blends: improvement of the photo-resistance through morphology modification

On the photo-oxidation behaviour of nano-filled polypropylene: role of the filler type and compatibilizer

Polymeric nanoparticles as a new generation of anti-oxidant carriers

In recent years, polymeric nanoparticles have been the object of growing scientific interest, especially as drug carriers. In this work, PEO-PPO-PEO (F127, commercial Pluronic F127®) nanoparticles has been used as carriers for naturally occurring anti-oxidant, such as quercetin (Q).

Polar Wax as Adhesion Promoter in Polymeric Blend Films for Durable Photovoltaic Encapsulants

Technological developments in the solar photovoltaic field must guarantee the high performance and low deterioration of solar cells in order for solar power plants to be more efficient and competitive. The solar cell needs comprehensive protection offered by a polymeric encapsulant, which improves UV stability, reduces water and moisture absorption, reduces oxygen and vapor permeability and enhances mechanical resistance. Moreover, high transparency and adhesion yields improved the solar panel performance. The current work analyzes polymeric films based on poly(ethylene-co-vinyl acetate) (EVA) and polyolefin (PO) for photovoltaic encapsulant use (the high temperature resistance is improved …

Foto-ossidazione di film nanocompositi a base LDPE/EVA

Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability

Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites’ electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes dur…

Regradation of Photooxidized Post-Consumer Greenhouse Films

Radical scavenging activity of ultrasound-treated Carbon Nanotubes

Carbon nanotubes (CNTs) having controlled radical activity have been achieved tuning the content of their lattice defects induced by an ultra-sound (us) treatment.

Photochenical behaviour of PE/PA polymer blends

EVA Copolymer Based Nanocomposites: Rheological Behavior Under Shear and Isothermal and Non-Isothermal Elongational Flow

Formulazione e Caratterizzazione dei “Compositi verdi” a Base di Materie Plastiche Post-Consumo e Cariche Organiche

Nanocomposites from Poly(Ethylene-co-Acrylic Acid) Copolymers and a Zn-Ionomer

EVA Copolymer Based Nanocomposites: Rheological Behavior Under Shear and Elongational Flow

Film blowing and characterization of PA6/LDPE blends