This research work has concerned a study on thermomechanical and crystallization properties of poly(lactic acid) (PLA) composites containing three different types of additives; namely: kenaf fiber (20 pph), Cloisite30B nanoclay (5 pph), and hexagonal boron nitrile (h-BN; 5 pph). The composites were prepared using a twin screw extruder before molding. Crystallization behaviors of the various composites were also examined using a differential scanning calorimetry. By adding the additives, tensile modulus of the polymer composites increased, whereas their tensile strength and elongation values decreased as compared to those of the neat PLA. Heat distortion temperature (HDT) values of the materials slightly increased, for about 3-5 C. However, after annealing at 100 C, HDT values of the fabricated PLA composites rapidly increased with annealing time before reaching a plateau after 10 min. The HDT values of above 120 C were achieved when 20 pph kenaf fiber was used as an additive. The above results were in a good agreement with DSC thermograms of the composites, indicating that percentage crystallinity of the materials increased on annealing and crystallization rate of the PLA/kenaf system was the highest.

This study has concerned preparation of polylactic acid grafted with maleated thermoplastic starch (PLA-g-MTPS) and a study on compatibilizing efficacy of the above copolymers in PLA/thermoplastic starch (TPS) blends. The PLA-g-MTPS copolymers were prepared by two-step reaction. First, maleated thermoplastic starch (MTPS) was prepared by reacting cassava starch with glycerol and maleic anhydride (MA). Second, the MTPS was grafted onto PLA molecules using peroxide as an initiator. Chemical structures of the products were characterized by using Fourier transform infrared spectroscopy and 1 H-NMR techniques, whereas the acid numbers of the copolymers were determined by titration. Thermal characteristic of the copolymer was also characterized by using dynamic mechanical thermal analysis. In total, 5 wt % of the graft copolymer was blended with PLA and TPS in a twin screw extruder. Mechanical, rheological, and morpho-logical properties of the blends were evaluated via tensile test, melt flow index test, and scanning electron microscopy, respectively. It was found that mechanical properties of the blends depended on starch content and type of the PLA-g-MTPS. When the PLA-g-MTPS was prepared at low amount (0.25 pph) of peroxide, the mechanical properties of the blend was improved remarkably as compared to those of the normal blend and/or the blend containing different compatibilizers. Compatibilizing efficacy of the above copolymers became more obvious when the thermoplastic starch (TPS) blending ratio was increased. The above results were ascribed in the light of change in the viscosity and morphology of the blends. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E388-E395, 2012

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This research work has concerned a study on relationship between structure and properties of maleated thermoplastic starch (MTPS)/plasticized poly(lactic acid) (PLA) blend. The aim of this work is to investigate the effects of blending time, temperature, and blend ratio on mechanical, rheological, and thermal properties of the blend. The MTPS was prepared by mixing the cassava starch with glycerol and maleic anhydride (MA). Chemical structure of the modified starch was characterized by using a FTIR technique, whereas the degree of substitution was determined by using a titration technique. After that, the MTPS prepared by 2.5 pph of MA was further used for blending with triacetin-plasticized PLA under various conditions. Mechanical, thermal, and rheological properties of the blends were evaluated by using a tensile test, dynamic mechanical thermal analysis, and melt flow index (MFI) test, respectively. It was found that tensile strength and modulus of the MTPS/PLA blend increased with the starch content, blending temperature, and time, at the expense of their toughness and elongation values. The MFI values also increased with the above factors, suggesting some chain scission of the polymers during blending. SEM images of the various blends, however, revealed that the blend became more homogeneous if the temperature was increased. The above effect was discussed in the light of transesterification. Last, it was found that mechanical properties of the PLA/MTPS blend were more superior to those of the normal PLA/TPS blends.

This study concerns the photodegradation and stabilization of a solar cell encapsulating material made from ethylene/vinyl acetate copolymer (EVA). EVA was compounded with various additives in a twin‐screw extruder. After that, the extruded film was cured in a hydraulic compression mold before being exposed to ultraviolet (UV) radiation at an ambient temperature for 800 h. The thermal stability of the material was also studied through the aging of the sample at 90°C for 2000 h. The tensile strength of the unstabilized EVA decreased only slightly after the thermal aging. On the other hand, the strength of the material decreased noticeably after the UV irradiation. Fourier transform infrared spectra of various EVA films revealed that there was no deacetylation occurring after the UV irradiation. However, results from the swelling test and swollen‐state NMR suggested that the polymer degraded via a chain‐scission mechanism. After compounding with some antioxidants, most of the EVA films scarcely degraded after the UV irradiation, with the exception of the EVA compounded with a combination of the aromatic phosphate compound (0.1 phr) and hindered amine light stabilizer (0.1 phr). The results are discussed in light of an antagonism effect that occurred because of the aforementioned combination. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

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Keratins were extracted from chicken feather waste by sulphitolysis method, using various sodium metabisulphite contents. The extracted keratin was characterized by FT-IR and gel electrophoresis (SDS-PAGE) techniques. The extracted keratin with the highest molecular weight (12-20 kDa) was then selected for further study on electrospinning. The keratin/PLA solutions with a variety of blending ratios (10/90 to 90/10 w/w) were prepared before fabrication by electrospinning process. Morphology of the electrospun fiber was examined by using SEM technique, From the results, it was found that keratin/PLA blends containing 90 %wt of keratin could not be electrospun into fiber. By decreasing the keratin content to below 70 %wt, the blend solution can be electrospun into fiber. FT-IR spectrum of the keratin/PLA fiber showed the presence of peaks representing both keratin and PLA. These results confirmed that the fiber composed of both polymeric phases.