Effect of compatibilization on the photo-oxidation behaviour of polyethylene/polyamide 6 blends and their nanocomposites

Abstract Polymer based nanocomposites are increasingly attracting interest from academia and industry, and the use of polymer blends as matrices greatly increase their potential field of application. In order to improve their characteristics, the use of compatibilizers acting on the blend components is mandatory. However, this also leads to rising concerns regarding the behaviour of polymer blend based nanocomposites upon being subjected to photo-oxidative degradation. It is known that morphology can deeply influence the photo-oxidative behaviour, and this can be therefore deeply influenced by the blend components and by the use of compatibilizers. In this work, polymer blend nanocomposites…

Simulation of a regeneration plant for spent pickling solutions via spray roasting

Nowadays, pyrohydrolysis techniques are widely applied for regeneration of spent pickling liquors providing an excellent environmental and economical strategy to the problem of waste disposal/recovery, also thanks to the high acid recovery efficiencies (>99%) achieved. In fact, in these processes, iron chlorides are converted into iron oxides and hydrogen chloride at high temperature in spray roasting or fluidized bed reactors. Though the state-of-the-art technologies have been successfully applied only to large-scale plants, the development of small-scale units, able to perform a delocalized regeneration of spent solutions where these latter are actually produced, would be strongly needed …

Influenza delle lavorazioni sulle proprietà di compositi a base di polimeri biodegradabili e farina di legno

Ecocompositi polimerici: polietilene riciclato e cariche organiche naturali

ECOCOMPOSITI MATER-BI®/FARINA DI LEGNO: OTTIMIZZAZIONE DELLE PROPRIETA’ ATTRAVERSO ANALISI STATISTICA E BIODEGRADAZIONE

Rheological Behaviour, Mechanical Properties and Processability of Biodegradable Polymer Systems for Film Blowing

Films for agricultural or packaging applications are typically made of low density polyethylene (LDPE). They are produced through the film blowing process, which requires the use of polymers with suitable rheological properties. Furthermore, the short shelf-life which is often related to many packed products leads to huge amounts of plastic-based wastes. This suggests the use of biodegradable and/or compostable polymers in replacement for traditional ones. To this regard, only few data exist on the rheological properties of biodegradable polymers undergoing film blowing processing. In this work, a detailed investigation on the rheological, mechanical and processability behaviour of some bio…

Prediction of the morphology of polymer-clay nanocomposites

Abstract Polymer nanocomposites have continually attracted increasing interest over the last decade, due to significant improvements they can offer compared to neat polymer matrices. However, the final morphology of a nanocomposite, determined by several variables, can significantly influence the macroscopic properties of the final product. Therefore, it is important to study the interactions between processing, morphology, structure and rheological properties, and the suitability of existing models in order to predict the system's behaviour with change of the main processing variables. In this work, the applicability of a predictive theory based on the Wu model was formulated and proposed …

Recovery of zinc from spent pickling solutions by liquid–liquid extraction using TBP

In this paper, recovery of zinc from real spent pickling solutions by liquid–liquid extraction with tributyl phosphate (TBP) was studied. In particular, the effects of some parameters were investigated, such as the volume ratio between the organic phase and real spent pickling liquor (O/A) (1:2, 1:1, 2:1, 4:1), the stirring time (5–20–30 min) and the TBP concentration (10%–55%–100%), in order to determine the conditions leading to higher zinc extraction efficiency, as well as selectivity in relationships to other metals such as iron. After zinc extraction, TBP was successfully regenerated. Among several tested solutions, water allows zinc recovery higher than 90%, especially at 10% diluted …

Green composites of organic materials and recycled post-consumer polyethylene

International audience; Addition of organic fillers to post‐consumer recycled plastics can give rise to several advantages. First of all, the cost of these fillers is usually very low, the organic fillers are biodegradable contributing to an improved environmental impact and, last but not least, some mechanical and thermomechanical properties can be enhanced. Organic fillers are not widely used in the plastic industry although their use is increasing. Bad dispersion into the polymer matrix at high‐level content and poor adhesion with the matrix are the more important obstacles to this approach. In this work various organic fillers have been used with a post‐consumer plastic material origina…

Composites from biodegradable polymers and wood flour

Green composites of organic materials and recycled post-consumer polyethylene

Compositi Verdi con Polietilene Riciclato e Cariche Organiche

Recent Developments and Formulations for Hydrophobic Modification of Carrageenan Bionanocomposites

Versatility of the anionic algal polysaccharide carrageenan has long been discussed and explored, especially for their affinity towards water molecules. While this feature is advantageous in certain applications such as water remediation, wound healing, etc., the usefulness of this biopolymer is extremely limited when it comes to applications such as food packaging. Scientists around the globe are carrying out research works on venturing diverse methods to integrate hydrophobic nature into these polysaccharides without compromising their other functionalities. Considering these foregoing studies, this review is designed to have an in-depth understanding of diverse methods and techniques ado…

Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of stabilizers

Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…

Biodegradation paths of Mater-Bi®/kenaf biodegradable composites

Composites obtained from biodegradable polymers and natural–organic fillers are attracting increasing interest, thanks to the environmental advantages they promise. On the other hand, the real biodegradation performance of a biodegradable polymer/natural organic filler composite should be assessed by performing specific biodegradation tests. These are often carried out under laboratory conditions, but more realistic conditions should be taken into account. In this work, a systematic study on the biodegradation of kenaf fiber-filled Mater-Bi® composites in different environments is presented, and some interesting parameters for the understanding of the optimum way to obtain a fast degradatio…

Creep Behavior of Poly(lactic acid) Based Biocomposites

Polymer composites containing natural fibers are receiving growing attention as possible alternatives for composites containing synthetic fibers. The use of biodegradable matrices obtained from renewable sources in replacement for synthetic ones is also increasing. However, only limited information is available about the creep behavior of the obtained composites. In this work, the tensile creep behavior of PLA based composites, containing flax and jute twill weave woven fabrics, produced through compression molding, was investigated. Tensile creep tests were performed at different temperatures (i.e., 40 and 60 °C). The results showed that the creep behavior of the composites is strongly inf…

Thermomechanical degradation of polyethylene/polyamide 6 blend-clay nanocomposites

Abstract Polymer nanocomposites are gaining a growing interest both in the academia and in the industrial field, because of some specific properties they can assure. However, the rise in the attention from the industry is also leading to concerns about their processing, which can involve issues which are not present in traditional polymers processing; furthermore, additional issues can arise when nanocomposites are based on a polymer blend rather than a single polymer. In this work, a systematic study on thermomechanical degradation and reprocessing behaviour of LDPE/PA6/Cloisite 15A systems has been performed. The characterization was based on rheological, mechanical and morphological anal…

Effect of Hot Drawing on the Mechanical Properties of Biodegradable Fibers

The use of biodegradable polymers is increasingly attracting interest over the last years, since they can reduce the environmental effects related to disposal of traditional plastics and, in general, the use of fossil, non-renewable resources. One of the most promising applications is represented by fibers production. However, the orientation and the crystallinity degrees can significantly affect the mechanical properties. Therefore, it is of interest to investigate on the optimum processing conditions, in order to improve the mechanical properties. In particular, while crystallinity can be slightly modified by the processing, orientation can be significantly improved. In this work, the eff…

Parthenolide prevents resistance of MDA-MB231 cells to doxorubicin and mitoxantrone: the role of Nrf2.

Triple-negative breast cancer is a group of aggressive cancers with poor prognosis owing to chemoresistance, recurrence and metastasis. New strategies are required that could reduce chemoresistance and increases the effectiveness of chemotherapy. The results presented in this paper, showing that parthenolide (PN) prevents drug resistance in MDA-MB231 cells, represent a contribution to one of these possible strategies. MDA-MB231 cells, the most studied line of TNBC cells, were submitted to selection treatment with mitoxantrone (Mitox) and doxorubicin (DOX). The presence of resistant cells was confirmed through the measurement of the resistance index. Cells submitted to this treatment exhibit…

Recycling and Thermomechanical Degradation of LDPE/Modified Clay Nanocomposites

The special features of polymer nanocomposites are continually gaining interest both in academia and in industry. The latter is especially experiencing an increase in interest towards this class of polymer composites, and this is leading to the first concerns about their reprocessing and reciclability. Here, a systematic study on the behavior of LDPE/Cloisite 15A systems upon reprocessing in a single-screw extruder is described, focusing on rheological, mechanical, and morphological properties changes. The investigated systems show a very complex thermomechanical degradation behavior, with the degradation of the clay modifier and different degradation paths involving the polymer matrix; all…

Effect of the processing techniques on the properties of ecocomposites based on vegetable oil-derived Mater-Bi® and wood flour

Polymer composites based on biodegradable polymers and natural-organic fillers are becoming more and more important because of their interesting properties in terms of environmental impact, manufacturing cost, and esthetic features. In particular, the use of biodegradable polymer matrices allows obtaining a full biodegradability. One of the most interesting biodegradable polymer families is the Mater-Bi® one. In this work, we investigated the processability, the influence of different processing techniques, and the influence of the filler particle size on the properties of Mater-Bi/wood flour composites. Injection molding caused a partial degradation of the macromolecular chains, whereas si…

Ecocompositi polimerici caricati con riempitivi organico-naturali

The Effects of Nanoclay on the Mechanical Properties, Carvacrol Release and Degradation of a PLA/PBAT Blend

The formulation of polymeric films endowed with the abilities of controlled release of antimicrobials and biodegradability is the latest trend of food packaging. Biodegradable polymer (Bio-Flex&reg

Degradation of polymer blends: A brief review

Abstract The usefulness of any material, including polymer blends, depends on its degradability and durability. The blend composition can significantly affect the degradative behavior of a polymer blend and can differ from the degradation routes of the pure components since the interactions among different species in the blends during degradation, and among the degradation products, can occur. These reactions can lead either to an acceleration of the degradation rate or to a stabilizing effect in comparison with the pure components. Thus, the additive rule cannot be often applied in case of degradation of polymer blends and, therefore, it is difficult to predict the degradative behavior of …

Biodegradable Polymers for the Production of Nets for Agricultural Product Packaging

It is well known that the need for more environmentally friendly materials concerns, among other fields, the food packaging industry. This regards also, for instance, nets used for agricultural product (e.g., citrus fruits, potatoes) packaging. These nets are typically manufactured by film blowing technique, with subsequent slicing of the films and cold drawing of the obtained strips, made from traditional, non-biodegradable polymer systems. In this work, two biodegradable polymer systems were characterized from rheological, processability, and mechanical points of view, in order to evaluate their suitability to replace polyethylene-based polymer systems typically used for agricultural prod…

Rheological Behavior Under Shear and Non-Isothermal Elongational Flow of Biodegradable Polymers for Foam Extrusion

The production of many items, in particular for food packaging applications, is based on foam extrusion and thermoforming. These operations require the use of polymers which can grant some specific rheological properties, both under shear and elongational flow. In this work, the behavior of some biodegradable polymers [Mater-Bi® and poly(lactic acid)] under shear and non-isothermal elongational flow was investigated and compared with a traditional, non-biodegradable polymer, in order to assess their suitability for industrial-scale foam extrusion and thermoforming. The rheological characterization evidenced the differences between the different biodegradable polymers and the reference polys…

Accelerated weathering of polypropylene/wood flour composites

Effect of the orientation and rheological behaviour of biodegradable polymer nanocomposites

Abstract The recent increasing interest towards biodegradable polymers has favoured the investigation on these systems, showing also their limits. On the other hand, the success achieved by nanocomposites has fostered the search for new systems where the polymer matrix is biodegradable. The final properties can depend on a number of factors, including the biodegradable polymer used as well as the nanosized filler, their mutual compatibility, the filler dispersion and the processing conditions. In this work, nanocomposites based on a starch-derived matrix and three different lamellar silicates were prepared, and the effects of the elongational flow on the dispersion, the improvement of inter…

Proprietà meccaniche di compositi poliolefinici caricati con riempitivi organico-naturali: utilizzo di prmotori di adesione

Effect of the processing on the properties of biopolymer based composites filled with wood flour

Wood-polymer composites (WPCs) are well known today in the field of industrial applications, because of several advantages they can grant if compared with mineral filler-polymer composites. These advantages regard the low cost of wood based fillers, the reduced specific weight, the lower hazards for production workers in case of inhalation, the special aesthetic features, environmental issues. The scientific literature reports studies regarding polymer matrices like, for instance, polyethylene and polypropylene, in combination with several natural-organic fillers. However, a limit of these composites is represented by the fact that there is not a full biodegradability: this, in fact, regard…

Unusual roles of caspase-8 in triple-negative breast cancer cell line MDA-MB-231

Triple-negative breast cancer (TNBC) is a clinically aggressive form of breast cancer that is unresponsive to endocrine agents or trastuzumab. TNBC accounts for ~10-20% of all breast cancer cases and represents the form with the poorest prognosis. Patients with TNBC are at higher risk of early recurrence, mainly in the lungs, brain and soft tissue, therefore, there is an urgent need for new therapies. The present study was carried out in MDA-MB-231 cells, where we assessed the role of caspase-8 (casp-8), a critical effector of death receptors, also involved in non‑apoptotic functions. Analysis of casp-8 mRNA and protein levels indicated that they were up-regulated with respect to the normal…

Preparation and Recycling of Plasticized PLA

Poly(lacticacid)(PLA)hasbeengainingarisinginterestoverthe last years as a biodegradable and environmental-friendly substitute of traditional non-biodegradable poly-mers.Several ways exist to synthesize PLA, however, poly-merization through lactide formation is the most used onindustrial scale, allowing to obtain optimum results interms of mechanical and thermal properties.

Effect of cold drawing on mechanical properties of biodegradable fibers.

Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be…

Orientation induced brittle – Ductile transition in a polyethylene/polyamide 6 blend

Abstract Polyamide/polyolefin blends are of scientific and technological interest but, on the other hand, the different chemical nature of the two components makes them incompatible, resulting in unsatisfactory physical properties and making compatibilization necessary. In particular, although the two components are ductile, the binary blends can show brittle behaviour. It is also known that the effect of the elongational flow (and then of the induced orientation) on polymer blends is a decrease of elongation at break with increase of the degree of orientation. In this work, the effect of orientation on the mechanical properties of a low density polyethylene/polyamide 6 incompatible blend w…

Effect of stress and temperature on the thermomechanical degradation of a PE-LD/OMMT nanocomposites

Thermomechanical degradation of nanocomposites is a topical issue that has not been fully investigated as demonstrated by the low number of papers available in the literature regarding this spe- cific aspect. In particular, with regards to low density polyethylene/clay nanocomposites, the degrada- tion behavior is very complex since it involves the degradation paths of both the polymer matrix and the organomodified nanoclay. In the present work, the effects of mechanical stress and temperature on the thermomechanical behavior of PE-LD/organomodified clay nanocomposites and the degradation paths were investigated by rheological, FT-IR and mechanical methods. The results have shown that the t…

LDPE/PA6/compatibilizer films: mechanical and rheological behaviour

Compositi "verdi" a base di polimeri biodegradabili e riempitivi organico-naturali

Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene

Polymer nanocomposites are currently a topic of great interest. The increasing importance they are gaining also in the standpoint of industrial applications, is giving concerns regarding their environmental stability and, in general, their behaviour in outdoor applications, under direct solar irradiation. Papers available in the literature have highlighted the different influences of different nanosized fillers, in particular clay-based nanofillers; however, few data are available regarding other nanosized fillers. Furthermore, the research on polymer nanocomposites has clearly pointed out that the use of compatibilizers is required to improve the mechanical performance and the dispersion o…

Rheological and Mechanical Behavior of LDPE/Calcium Carbonate Nanocomposites and Microcomposites

The increase of the interest in polymer nanocomposites has been leading to continuous growing search toward nanofillers alternative to the widely known clay-based ones. One of these possible alternatives is represented by calcium carbonate nanoparticles, which have not been widely investigated in such context. In this article, a study on the rheological and morphological behavior of dif- ferent low density polyethylene-calcium carbonate nanocomposites, compared with a reference calcium carbonate microcomposite, is presented. Several different nanosized calcium carbonates at different amounts were used. The results from the rheological and me- chanical tests outlined that only minor changes …

Processability and biodegradation of wood/biopolymer composites

Hedysarum coronarium-Based Green Composites Prepared by Compression Molding and Fused Deposition Modeling

In this work, an innovative green composite was produced by adding Hedysarum coronarium (HC) flour to a starch-based biodegradable polymer (Mater-Bi®, MB). The flour was obtained by grinding together stems, leaves and flowers and subsequently sieving it, selecting a fraction from 75 μm to 300 μm. Four formulations have been produced by compression molding (CM) and fused deposition modeling (FDM) by adding 5%, 10%, 15% and 20% of HC to MB. The influence of filler content on the processability was tested, and rheological, morphological and mechanical properties of composites were also assessed. Through CM, it was possible to obtain easily homogeneous samples with all filler amounts.…

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

Effect of ultraviolet and moisture action on biodegradable polymers and their blend

In this work, the suitability of polylactic acid (PLA), polybutylene adipate terephthalate (PBAT) and PBAT/PLA blend samples to outdoor applications were investigated in terms of mechanical, morphological and visual properties in presence of ultraviolet action and water, finding that PLA in particular can be actually considered for such applications.

Photooxidation Behavior of a LDPE/Clay Nanocomposite Monitored through Creep Measurements

Creep behavior of polymer nanocomposites has not been extensively investigated so far, especially when its effects are combined with those due to photooxidation, which are usually studied in completely independent ways. In this work, the photooxidation behavior of a low density polyethylene/organomodified clay nanocomposite system was monitored by measuring the creep curves obtained while subjecting the sample to the combined action of temperature, tensile stress, and UV radiation. The creep curves of the irradiated samples were found to be lower than those of the non-irradiated ones and progressively diverging, because of the formation of branching and cross-linking due to photooxidation. …

DEGRADATION OF MATER-BI /WOOD FLOUR BIOCOMPOSITES IN ACTIVE SEWAGE SLUDGE

The mechanical properties of Mater-Bi® are, in general, not adequate for certain applications and the addition of a filler is therefore necessary. Among the different fillers, natural fibres are particularly interesting because they potentially allow improving the performance of the material without compromising its biodegradability. In order to improve the basic mechanical properties of a Mater-Bi grade and to obtain a new, fully biodegradable material, wood flour based composites were prepared by different processing methods. To simulate actual and not laboratory bacterial attack on the prepared materials, in this work we studied the biodegradation of the composites in a real active sewag…

Eco-compositi a base di polietilene riciclato

CHARACTERIZATION OF BIOPOLYMER BASED COMPOSITES FILLED WITH WOOD FLOUR.

Lavorazione e proprietà meccaniche del polipropilene con cariche organiche

Mechanical behaviour of Mater-Bi/wood flour composites: a statistical approach

Interest in biocomposites (lignocellulosic filled biopolymers) started in the 90s, due to environmental advantages, related to the full biodegradability of both matrix and filler, economical issues (organic fillers usually come from sawmill or agriculture wastes) and aesthetical issues (wood filled biopolymers could be particularly pleasant if used for indoor furnishing and automotive interior). In this work, a method for a systematic study of the properties of Mater-Bi®/wood flour composites is presented. A two-level full factorial model was built. It allows investigating the effects of multiple operative variables on the observed properties, their contributions, their optimal combinations…

An Overview of Functionalized Graphene Nanomaterials for Advanced Applications

Interest in the development of graphene-based materials for advanced applications is growing, because of the unique features of such nanomaterials and, above all, of their outstanding versatility, which enables several functionalization pathways that lead to materials with extremely tunable properties and architectures. This review is focused on the careful examination of relationships between synthetic approaches currently used to derivatize graphene, main properties achieved, and target applications proposed. Use of functionalized graphene nanomaterials in six engineering areas (materials with enhanced mechanical and thermal performance, energy, sensors, biomedical, water treatment, and c…

Injection Molding and Mechanical Properties of Bio-Based Polymer Nanocomposites

The use of biodegradable/bio-based polymers is of great importance in addressing several issues related to environmental protection, public health, and new, stricter legislation. Yet some applications require improved properties (such as barrier or mechanical properties), suggesting the use of nanosized fillers in order to obtain bio-based polymer nanocomposites. In this work, bionanocomposites based on two different biodegradable polymers (coming from the Bioflex and MaterBi families) and two different nanosized fillers (organo-modified clay and hydrophobic-coated precipitated calcium carbonate) were prepared and compared with traditional nanocomposites with high-density polyethylene (HDPE…

Compatibilization of a polyethylene/polyamide 6 blend nanocomposite

Polymer blends of incompatible components need to be compatibilized to give rise to a blend with good properties. At the same way, polymer/clay nanocomposites show the same problem because of different chemical nature of the polymer matrix and of the clay. Compatibilization is then necessary if an incompatible polymer blend is filled with an organomodified clay. In this work a polyethylene/polyamide 6 blend filled with an organomodified clay has been compatibilized with a maleic anyhidride grafted SEBS (styrene-ethylene-butylene-styrene) copolymer and a glicidylmethacrylate-ethylene copolymer. The results show that compatibilization improves the mechanical properties in terms of elongation …

Green Composites of Biodegradable Polymers and Natural Organic Fillers

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, …

“Compatibilization” through Elongational Flow Processing of LDPE/PA6 Blends

Polyamide/polyolefin blends have gained attention from the academia and the industry for several years. However, in order to optimize their properties, some drawbacks such as chemical incompatibility must be adequately overcome. This can be done by adding suitable compatibilizers. On the other hand, it is less known that suitable processing techniques may also lead to significant results. In a previous work on a low-density polyethylene/polyamide 6 (LDPE/PA6) blend, we found that the orientation due to elongational flow processing conditions could lead to an unexpected brittle&ndash

Preparazione e caratterizzazione di polimeri biodegradabili caricati con riempitivi organico-naturali

Effect of small amounts of poly(lactic acid) on the recycling of poly(ethylene terephthalate) bottles

Abstract Poly(ethylene terephthalate) (PET) is one of the most used commodity polymers, especially for food and beverage applications, and its recycling is of great importance because of the possible use in the textile and construction industries. On the other hand, the interest in biodegradable polymers has led, in recent years, to the use of materials such as poly(lactic acid) (PLA) also in the food and beverage industry. The presence of small amounts of PLA in the PET waste can significantly affect the post-consumer recycling process. In this work, the effect of the presence of small amounts of PLA on the recycling of PET bottles is investigated by rheological, mechanical, morphological …

Rheological and mechanical properties of biodegradable nanocomposites

Polymer nanocomposites have gained huge interest over the last decade. However, traditional thermoplastic nanocomposites do not match the rising concern about environmental issues. Therefore, during the last years, the search for biodegradable polymer nanocomposites is gaining importance. Most of biobased (i.e. based on biodegradable/bioderived polymer matrices) nanocomposites have poly(lactic acid), PLA, as matrix. However, it is of clear interest to take into account also different biobased polymer matrices, such as MaterBi. In this work, we prepared bionanocomposites containing MaterBi or a PLA-based polymer matrix, with two different kinds of nanofillers (organomodified clay and nanosiz…

Green composites: A brief review

The rising concern towards environmental issues and, on the other hand, the need for more versatile polymer-based materials has led to increasing interest about polymer composites filled with natural-organic fillers, i.e. fillers coming from renewable sources and biodegradable. The composites, usually referred to as "green", can find several industrial applications. On the other hand, some problems exist, such as worse processability and reduction of the ductility. The use of adhesion promoters, additives or chemical modification of the filler can help in overcoming many of these limitations. These composites can be further environment-friendly when the polymer matrix is biodegradable and c…

Durability of biodegradable polymers for the conservation of cultural heritage

The use of polymers for conservation of cultural heritage is related to the possibility to slow down or stop natural deterioration which, in many cases, corresponds to stopping the entrance of liquid water and to favour spontaneous water vapour removal. Unfortunately, hydrophobicity is generally favoured by surface roughness and thus competitive with transparency. It is therefore important to find an optimal balance hydrophobicity, transparency and durability (especially to photooxidation). However, polymers typically used for applications in this field come from non-renewable resources and are not biodegradable. In this work, the mechanical, structural and optical properties of PLA, PBAT a…

Eco-compositi a base di polietilene riciclato e riempitivi naturali

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

Improving the mechanical properties of polyolefin-natural organic filler composites

Properties of recycled polyethylene/organic fillers green composites

Accelerated weathering of polypropylene/wood flour composites

Abstract Wood–plastic composites (WPCs) have received increasing attention during the last decades, because of many advantages related to their use. Some of their main applications are represented by outdoor furnishing and decking; therefore, it is important to assess their behaviour under UV exposure. In this work, polypropylene/wood flour composites were prepared and their resistance to photooxidation investigated. The composites were prepared by extrusion and compression moulding, and were subjected to mechanical tests, FTIR analysis and molecular weight measurements. The results showed that the composites retained a higher fraction of the original mechanical properties after accelerated…

Mechanical, Thermomechanical and Reprocessing Behavior of Green Composites from Biodegradable Polymer and Wood Flour

The rising concerns in terms of environmental protection and the search for more versatile polymer-based materials have led to an increasing interest in the use of polymer composites filled with natural organic fillers (biodegradable and/or coming from renewable resources) as a replacement for traditional mineral inorganic fillers. At the same time, the recycling of polymers is still of fundamental importance in order to optimize the utilization of available resources, reducing the environmental impact related to the life cycle of polymer-based items. Green composites from biopolymer matrix and wood flour were prepared and the investigation focused on several issues, such as the effect of r…

Compatibilization of polyethylene/polyamide 6 blend nanocomposite films

Polymer blends of incompatible components need to undergo compatibilization, in order to give rise to a blend with good physical properties. At the same way, polymer/clay nanocomposites show this problem because of different chemical nature of the polymer matrix and of the clay. Compatibilization is therefore more necessary if an incompatible polymer blend is filled with an organomodified clay in order to give a final material with good properties. In this work, a polyethylene/polyamide 6 blend filled with an organomodified clay has been compatibilized with a maleic anhydride grafted SEBS (styrene-ethylene-butylene-styrene) copolymer and a glicidylmethacrylate-ethylene copolymer. The result…

Green Composites Based on PLA and Agricultural or Marine Waste Prepared by FDM

Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic …

Thermomechanical Analysis of Isora Nanofibril Incorporated Polyethylene Nanocomposites

The research on cellulose fiber-reinforced nanocomposites has increased by an unprecedented magnitude over the past few years due to its wide application range and low production cost. However, the incompatibility between cellulose and most thermoplastics has raised significant challenges in composite fabrication. This paper addresses the behavior of plasma-modified polyethylene (PE) reinforced with cellulose nanofibers extracted from isora plants (i.e., isora nanofibrils (INFs)). The crystallization kinetics of PE&ndash

Effect of elongational flow on morphology and properties of polymer/CNTs nanocomposite fibers

Carbon nanotubes (CNTs) have been attracting increasing interest for the fabrication of polymer-based nanocomposites because of their excellent properties. Traditional methods for the preparation of polymer/CNTs nanocomposites are in situ polymerization, solution blending, and melt mixing. The achievement of a good CNT dispersion and a percolation network is important in order to obtain better mechanical and electrical properties. However, the rheological behavior of polymer/CNTs systems, in particular regarding the extensional flow, has not been much investigated so far. In this work we present, for the first time, rheological data in non-isothermal extensional flow and an investigation on…

Characterization and biodegradability of biodegradable polymer-wood flour composites

Creep response of a LDPE-based nanocomposite

Polymer nanocomposites and their behavior have been widely investigated by several paths, including mechanical, rheological, and permeability tests, finding that several parameters (such as the polymer matrix, the nanofiller, their amounts, the presence of compatibilizers, processing parameters, etc.) can influence the main properties. However, less information is available regarding the creep response of polymer nanocomposites; in particular, few or no data are reported about the combined effect of different loads and different temperatures. In this article, the creep behavior of a low density polyethylene/organomodified clay nanocomposite has been investigated. The characterization of vis…

Photo-oxidation of nano- and micro-filled polypropylene

Degradation and Recycling of Films Based on Biodegradable Polymers: A Short Review

The environmental performance of biodegradable materials has attracted attention from the academic and the industrial research over the recent years. Currently, degradation behavior and possible recyclability features, as well as actual recycling paths of such systems, are crucial to give them both durability and eco-sustainability. This paper presents a review of the degradation behaviour of biodegradable polymers and related composites, with particular concern for multi-layer films. The processing of biodegradable polymeric films and the manufacturing and properties of multilayer films based on biodegradable polymers will be discussed. The results and data collected show that: poly-lactic…

Green Composites Based on Mater-Bi® and Solanum lycopersicum Plant Waste for 3D Printing Applications

3D printability of green composites is currently experiencing a boost in importance and interest, envisaging a way to valorise agricultural waste, in order to obtain affordable fillers for the preparation of biodegradable polymer-based composites with reduced cost and environmental impact, without undermining processability and mechanical performance. In this work, an innovative green composite was prepared by combining a starch-based biodegradable polymer (Mater-Bi®, MB) and a filler obtained from the lignocellulosic waste coming from Solanum lycopersicum (i.e., tomato plant) harvesting. Different processing parameters and different filler amounts were investigated, and the obtained sample…

Processing and mechanical properties of organic filer-polypropylene composites

The addition of organic fillers into thermoplastic polymers is an interesting issue, which has had growing consideration and experimentation during the last years. It can give rise to several advantages. First, the cost of these fillers is usually very low. Also, the organic fillers are biodegradable (thus contributing to an improved environmental impact), and finally, some mechanical and thermomechanical properties can be enhanced. In this study, the effect of the addition of different organic fillers on the mechanical properties and processability of an extrusion-grade polypropylene were investigated. The organic fillers came from natural sources (wood, kenaf, and sago) and were compared …

Mechanical properties of recycled polyethylene ecocomposites filled with natural organic fillers

The use of natural organic fillers in addition to postconsumer recycled polymers is getting a growing interest during the last years; this is due to many advantages they can provide in terms of cost, aesthetic properties, environmental impact. In this work, several types of wood flour (differing each other with regard to production source and particle size) were added to a recycled polyethylene coming from films for greenhouses and the effects of filler type, content, and size were investigated. Investigation was then focused on the improvement of mechanical properties, through the addition of polar copolymers (ethylene-co-acrylic acid, ethylene-vinyl acetate) and a maleic anhydride-grafted…

Improving the properties of polypropylene–wood flour composites by utilization of maleated adhesion promoters

Polymer composites filled with natural organic fillers have gained a significant interest during the last few years, because of several advantages they can offer compared with properties of inorganic-mineral fillers. However, these composites (based, in most cases, on polyolefins) often show a reduction in some mechanical properties. This is mainly due to the problems regarding dispersion of the polar filler particles in the non-polar polymer matrix and their interfacial adhesion with polymer chains. In this work, polypropylene-wood flour composites were prepared and the effect of the addition of a maleated polypropylene was investigated. The two materials were compounded by an industrial c…

Characterization of green composites from biodegradable polymers and wood flour.

Effect of adding wood flour to the physical properties of a biodegradable polymer

Wood flour/polymer composites (WPC) gained a significant interest during the last decades, due to several advantages related to the use of a natural-organic filler rather than an inorganic-mineral one. However, most of the studies have been performed on composites based on polyolefin matrices. A further step is the use of biodegradable polymers instead of traditional ones. In this work, wood flour (WF), under the form of short fibers, with two different sizes (coarse and fine) was added to a corn starch based biodegradable polymer of the Mater-Bi family. The effect of WF size, WF content, thermal treatment on the mechanical properties was investigated. The tensile mechanical tests showed an…

Kenaf-filled biodegradable composites: rheological and mechanical behaviour

Biodegradable polymer composites, typically based on biodegradable polymer matrices and natural-organic fillers, are gaining rising interest and importance over the last few years. Several natural-organic fillers can be used but the most widespread so far is wood, in the form of fibres or flour. Alternative cellulosic fillers can ensure advantages in terms of resource utilization and properties of the final composite. In this work, Mater-Bi® based biodegradable composites were prepared with two kinds of wood flour, and directly compared with alternative composites containing kenaf fibres. The use of kenaf fibres allowed improved elastic modulus, tensile strength and interaction with the pol…

Compatibilization of Polypropylene/Polyamide 6 Blend Fibers Using Photo-Oxidized Polypropylene.

The use of polyamide/polyolefin blends has gained importance and concern for years, but they also show some issues to be adequately addressed, such as the incompatibility between the two components. This is usually overcome by using suitable compatibilizers, typically based on functionalized polyolefins. However, there is only little information about the use of a degraded polyolefins to induce compatibilization. This is even truer, as far as polyamide 6/polypropylene (PA6/PP) blends are concerned. In this work, compatibilization of PA6/PP blends by using small amounts of photo-oxidized PP was investigated

Compositi polimerici con riempitivi organico-naturali

Mechanical properties of recycled polyethylene ecocomposites filled with natural organic fillers

The use of natural organic fillers in addition to postconsumer recycled polymers is getting a growing interest during the last years; this is due to many advantages they can provide in terms of cost, aesthetic properties, environmental impact. In this work, several types of wood flour (differing each other with regard to production source and particle size) were added to a recycled polyethylene coming from films for greenhouses and the effects of filler type, content, and size were investigated. Investigation was then focused on the improvement of mechanical properties, through the addition of polar copolymers (ethylene-co-acrylic acid, ethylene-vinyl acetate) and a maleic anhydride-grafted…

Gas Barrier, Rheological and Mechanical Properties of Immiscible Natural Rubber/Acrylonitrile Butadiene Rubber/Organoclay (NR/NBR/Organoclay) Blend Nanocomposites

In this paper, gas permeability studies were performed on materials based on natural rubber/acrylonitrile butadiene rubber blends and nanoclay incorporated blend systems. The properties of natural rubber (NR)/nitrile rubber (NBR)/nanoclay nanocomposites, with a particular focus on gas permeability, are presented. The measurements of the barrier properties were assessed using two different gases—O2 and CO2—by taking in account the blend composition, the filler loading and the nature of the gas molecules. The obtained data showed that the permeability of gas transport was strongly affected by: (i) the blend composition—it was observed that the increase in acrylonitrile butadiene rubber compon…