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INTRODUCTION Over the past few years, several studies have been highlighting the great potential of ?-glucans as a multifunctional modulators of wound healing alone and/or incorporated in a polymeric matrix [1]. ?-glucans represent the major components of cell walls of bacteria, fungi, yeast and cereals, mainly oat and barley, and their structural and biological properties strictly depend on the source. Among them, barley ?-glucans are extensively studied as they have shown interesting antimicrobial and wound healing properties [2]. In this study, ?-glucan based mixtures (containing proteins, fats and other polysaccharides, such as starch) were extracted from barley at different pH, through a very simple and low cost extraction process. The obtained mixtures were then employed for film preparation and the cell biocompatibility was studied. To this aim, different cell lines involved in wound healing, human dermal fibroblasts (HDF) and human umbilical vein endothelial cells (HUVEC), were used through direct and indirect in vitro assays (following ISO 10993-5 guidelines). The viability and migration of fibroblast and endothelial cells were analysed by using the in vitro scratch wound healing assay. In addition, cell adhesion was investigated by confocal microscopy. Furthermore, the effect on inflammation response modulation, was carried out on a murine macrophage J774 cell line in order to assess the effects of ?-glucan on inflammatory and anti-inflammatory cytokines production (IL-6, IL-10, IL-1?). The results suggested that ?-glucan films supported cell proliferation and migration. Moreover, these films are able to modulate the inflammation process in terms of inflammatory and anti-inflammatory cytokines levels.

In order to design new antimicrobial nanocomposites with properties for food packaging application, films of polypropylene random copolymer (PPR), PPR/Poly-β-pinene (PβP), PPR/clay and PPR/PβP/clay were prepared by melt extrusion. Structural, morphological, mechanical, barrier, antimicrobial properties and thermal stability of the films were determined. PPR and PβP always form a homogeneous system in the amorphous phase; in the binary PPR/clay system, PPR molecules intercalate the clay galleries; in the ternary PPR/PβP/clay system, the miscibility between PPR and PβP prevents the intercalation of the PPR macromolecules into the clay galleries. The addition of clay and PβP increased the thermal stability and the tensile mechanical properties of PPR and reduced the oxygen transmission rate and the water vapor transmission rate compared with plain PPR. Films of nanomaterials containing PβP provided a reduction of the test microorganisms (Escherichia coli 25922) of 24% comparing to the control (PPR/clay film). Copyright © 2015 John Wiley & Sons, Ltd.

In this work, the effect of different morphologies of nanoparticles synthesized by sol-gel technique, on polymer properties (such as photo-degradation resistance to UV-irradiation, thermal, physic-chemical and mechanical properties, wear resistance etc.) will be presented. The process conditions for preparation of ZnO nanocomposites will be optimized. The novel nanocomposites will be used as material with improved antibacterial activity.

We report on the effect of processing conditions on rheology, thermal and electrical properties of nanocomposites containing 0.02-0.3 wt % multiwall carbon nanotubes in an epoxy resin. The influence of the sonication, the surface functionalization during mixing, as well as the application of external magnetic field (EMF) throughout the curing process was examined. Rheological tests combined with optical microscopy visualization are proved as a very useful methodology to determine the optimal processing conditions for the preparation of the nanocomposites. The Raman spectra provide evidence for more pronounced effect on the functionalized with hardener compositions, particularly by curing upon application of EMF. Different chain morphology of CNTs is created depending of the preparation conditions, which induced different effects on the thermal and electrical properties of the nanocomposites. The thermal degradation peak is significantly shifted towards higher temperatures by increasing the nanotube content, this confirming that even the small amount of carbon nanotubes produces a strong barrier effect for the volatile products during the degradation. The ac conductivity measurements revealed lower values of the percolation threshold (pc) in the range of 0.03-0.05 wt %. CNTs for the nanocomposites produced by preliminary dispersing of nanotubes in the epoxy resin, compared to those prepared by preliminary functionalization of the nanotubes in the amine hardener. This is attributed to the higher viscosity and stronger interfacial interactions of the amine hardener/CNT dispersion which restricts the reorganization of the nanotubes. The application of the EMF does not influence the pc value but the dc conductivity values (?dc) of the nanocomposites increased at about one order of magnitude due to the development of the aforementioned chain structure

The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system.

The chemical modification by melt-mixing of an EBAGMA terpolymer with LDPE and PET was investigated with the aim to use these EBAGMA/LDPE and EBAGMA/PET blends (in equal weight quantities) as compatibilizer master batches to improve the compatibility of the LDPE/PET system. It is shown that when the EBAGMA terpolymer is melt blended with LDPE, almost 40% of the initial amount of EBAGMA is linked to the LDPE backbone. In contrast, in the case of EBAGMA/PET, FT-IR spectra indicate the total reactivity between the two components through the reaction of the epoxy group of EBAGMA with the PET terminal groups. SEM analysis shows that both master batches present two well-interconnected phases.

The isothermal crystallization behavior and the structure and morphology of isotactic poly(propylene) (iPP) and iPP/hydrogenated hydrocarbon resin (HR) 90/10 blend were analyzed. To cover the entire temperature range, isothermal crystallizations were studied using superfast calorimetry at a high cooling rate in the range 0 to 110 °C, and by conventional DSC at a low cooling rate in the range 120 to 140 °C. Structural and morphological changes due to the different thermal treatments were also analyzed. The complete crystallization curve ranging from Tg to Tm showed bimodal crystallization behaviors for both iPP and iPP/HR 90/10 blend. This result is explained by taking into consideration the polymorph properties of iPP. It is in fact assumed that the curve from Tg to 60 °C referred mainly to the crystallization kinetics of the iPP mesomorphic form by homogeneous nucleation, whereas the curve from 60 °C to Tm mainly represented the crystallization kinetic curve for the monoclinic form by heterogeneous nucleation. This hypothesis is confirmed by the analysis of the structures obtained using wide angle X-ray experiments. Moreover, the addition of HR to iPP causes a drastic reduction in the crystallization rate of iPP in both regions due to the diluent effect of the miscible resin.

The isothermal crystallization behavior and the structure and morphology of isotactic poly(propylene) (iPP) and iPP/hydrogenated hydrocarbon resin (HR) 90/10 blend were analyzed. To cover the entire temperature range, isothermal crystallizations were studied using superfast calorimetry at a high cooling rate in the range 0 to 110 8C, and by conventional DSC at a low cooling rate in the range 120 to 140 8C. Structural and morphological changes due to the different thermal treatments were also analyzed. The complete crystallization curve ranging from Tg to Tm showed bimodal crystallization behaviors for both iPP and iPP/HR 90/10 blend. This result is explained by taking into consideration the polymorph properties of iPP. It is in fact assumed that the curve from Tg to 60 8C referred mainly to the crystallization kinetics of the iPP mesomorphic form by homogeneous nucleation, whereas the curve from 60 8C to Tm mainly represented the crystallization kinetic curve for the monoclinic a form by heterogeneous nucleation. This hypothesis is confirmed by the analysis of the structures obtained using wide angle X-ray experiments. Moreover, the addition of HR to iPP causes a drastic reduction in the crystallization rate of iPP in both regions due to the diluent effect of the miscible resin.

The system formed by a polypropylene containing random low ethylene content (EP copolymer) of and a hydrogenated hydrocarbon resin (HR) is investigated in order to study the influence of resin (up to 20% in wt) on properties of blends and derived films. The random EP copolymer used is MoplenEP2C37F and the resin is MBG273 of Hercules Chemical Co. DSC and DMTA analyses of the blends show increase of Tg with resin content indicating that the two components are compatible in the amorphous phase. WAXD spectra show that MBG273 influences slightly the crystalline structure of EP copolymer. In fact the diffractograms of the EP copolymer and 95/5 blend present, beside the predominant peak of form, also a small span denoting presence of form; this span is not detectable on spectra of 90/10 and 80/20 samples. The crystallization during the cooling is found to be only lightly delayed by the HR: in fact, only 4 degrees is the difference between the Tc values of EP copolymer and 80/20 blend. Stress-strain test performed at room temperature show that MBG273 induces increase of Young's modulus and small decrease of elongation at break as function of resin content. An important effect is on the water vapour permeability, which decreases with resin content. The permeability and tensile properties are related to the increase of the glass transition with the addition of MBG273 that transforms gradually the amorphous of the material from rubbery to glassy. The results reported in this work indicate that an addition of 5-10% of MBG273 changes favourably properties, as Young' modulus and water vapour permeability, of an EP copolymer designed for the production of films for packaging application.

In this study, we investigated the influence of ZnO particles obtained by spray pyrolysis with submicron dimensions on the structure, morphology, thermal stability, photodegradation stability, mechanical and antibacterial properties of isotactic polypropylene (iPP)/ZnO composites prepared by melt mixing. The results of the morphological analyses indicate that, despite the surface polarity mismatch between iPP and ZnO, the extrusion process and the unique characteristics of the utilized particles allow a composite with a fair distribution of particles to be obtained, although some agglomeration phenomena can occur, which primarily depends on the composition of the composite. The addition of ZnO particles imparts significant improvements on the photodegradation resistance of iPP to ultraviolet irradiation, which confirms that ZnO particles act as screens for this type of radiation. The thermal stability of the iPP/ZnO composites is improved with respect to that of neat iPP and increases with the content of ZnO. The iPP/ZnO composites exhibit significant antibacterial activity against Escherichia coli. This activity is dependent on exposure time and composition. In the graph, the effect in the antibacterial activity of time and filler content in isotactic polypropylene (iPP)/ZnO composites is reported. Neat iPP has no bactericidal activity. For the composites, a decrease in the E. coli concentration is observed by increasing time. The effect is more evident for iPP/ZnO 95/5.