MODIFICA SUPERFICIALE DI FILM DI POLY(ETILENE-co-ACIDO ACRILICO) CON NANOPARTICELLE DI SILICE ATTIVATA

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

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

MECHANICAL PROPERTIES AND BIODEGRADABILITY OF MATER-BI®/WOOD FLOUR ECOCOMPOSITES

GREEN COMPOSITES BASED ON BIODEGRADABLE POLYMERS AND WOOD FLOUR

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…

A NEW ROUTE TO OBTAIN PANI-EAA FLEXIBLE FILMS

SCAFFOLDS POLILATTIDICI PER APPLICAZIONI BIOMEDICHE

Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles

In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of -COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmo…

Polymer-based 'green' composites

Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends

This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), inst…

Processing-structure-property relationships of electrospun PLA-PEO membranes reinforced with enzymatic cellulose nanofibers

Abstract Three different solvent mixtures were used to prepare electrospun membranes based on polylactic acid (PLA), polyethylene oxide (PEO) and enzymatic cellulose nanofibers (CNF). The materials were characterized from a morphological, spectroscopic, mechanical and rheological point of view. Furthermore, swelling test were performed in order to assess the water uptake of each sample. The results put into evidence that the choice of the solvents affects the structure and the properties of the membranes. Among the protocols tested, using chloroform/acetone/ethanol mixture was found to allow a high degree of CNF dispersion and a good electrospinnability of polymer solutions. These features …

Processability and biodegradation of wood/biopolymer composites

3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-ba…

PREPARATION OF POROUS POLYLACTIDE MATERIALS FOR BIOMEDICAL APPLICATIONS

UN NUOVO METODO PER OTTENERE FILM FLESSIBILI EAA-PANI

Biocomposite PBAT/lignin blown films with enhanced photo-stability.

Lignin can be obtained as a byproduct during cellulose-rich pulp fibers production and it is habitually treated as waste or intended for low-value destinations. However, due to UV absorption and mechanical properties, lignin can contribute to the fabrication of biodegradable blown films with superior performances. In this study, it was established the suitability of lignin for manufacturing biocomposite PBAT blown films with higher stiffness and photo-oxidation resistance. The effect of the filler concentration on the melt rheological behavior in non-isothermal elongational flow was investigated. The results allowed us to choose the correct filler concentration for producing films through a…

Biodegradable polymer-wood flour composites: main properties and biodegradability

During the last years, a considerably increasing rate of attention has arisen on biodegradable polymers. In the meanwhile, the use of wood-plastic composites (WPC) has grown in importance, especially in the United States. The combination of biodegradable polymers and wood-based fillers allows obtaining the typical advantages achievable with the use of WPCs, with the further advantage of the biodegradability and compostability of the matrix (and not only of the filler). In this work, the characterization and the biodegradability assessment of Mater-Bi®-wood flour composites have been carried out.

SURFACE MODIFICATION OF EAA WITH FUNCTIONALIZED SILICA NANOPARTICLES

Characterization and biodegradability of biodegradable polymer-wood flour composites

A new route for the preparation of flexible skin–core poly(ethylene-co-acrylic acid)/polyaniline functional hybrids

Abstract Surface modification of polymeric films is a way to obtain final products with high performance for many specific and ad hoc tailored applications, e.g. in functional packaging, tissue engineering or (bio)sensing. The present work reports, for the first time, on the design and development of surface modified ethylene–acrylic acid copolymer (EAA) films with polyaniline (PANI), with the aim of inducing electrical conductivity and potentially enable the electronic control of a range of physical and chemical properties of the film surface, via a new “grafting from” approach. In particular, we demonstrate that PANI was successfully polymerized and covalently grafted onto flexible EAA su…

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…

PREPARATION OF THERMOPLASTIC MATERIALS FOR BIOMEDICAL APPLICATIONS