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Biodegradable composite films of poly(lactic acid) (PLA) modified with varying amounts of capsicum oleoresin (CO)‐impregnated nanoporous silica (SiCO) were prepared. The antimicrobial and thermomechanical properties of the PLA composites were carefully investigated. The Gram‐positive pathogenic bacteria (Staphylococcus aureus and Bacillus) and the Gram‐negative pathogenic bacteria (Escherichia coli and Salmonella enterica) tests established excellent antimicrobial properties of the composites even at small concentrations of SiCO. The microscopic (scanning electron micrograph) and spectroscopic (energy‐dispersive X‐ray) investigations manifested the uniformity of particle distribution. Although the addition of CO slightly decreased the thermal stability of the composite films, it marginally enhanced the mechanical properties and crystallinity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47825. [ABSTRACT FROM AUTHOR]

The purpose of this study is to develop polymer composite masterbatches by using poly(lactic) acid as a carrier resin and bamboo charcoal particle as a natural pigment. Moreover, antioxidant and dispersing agent were added to the masterbatches where the antioxidant improves thermal and ultraviolent stability of pigment masterbatches while dispersing agent enhances the distribution and dispersion of bamboo charcoal particles in the polymer matrix. The natural pigment masterbatches were diluted in the poly(lactic) acid matrix. The morphology, thermal property, and rheological properties of bamboo charcoal particles/poly(lactic) acid composites comparing before and after weathering tests are studied. It was concluded that natural pigment charcoal masterbatches can make good bamboo charcoal particles/poly(lactic) acid composites for high‐temperature food packaging applications. [ABSTRACT FROM AUTHOR]

The polylactic acid is modified with porous silica-containing varying amount of capsicum oleoresin. The effect of accelerated weathering on the polymer degradation, thermomechanical, antibacterial, and rheological properties was studied. The accelerated weathering test was performed for 260 and 520h. The prepared composites show antimicrobial activity against gram-positive and gram-negative bacteria. The tensile strength, modulus, and percentage crystallinity of the composites increased by 17, 7, and 33% respectively with the addition of 1.54 wt% of capsicum oleoresin impregnated porous silica. On the other hand, the incorporation of capsicum oleoresin impregnated porous silica reduced shear modulus and shear viscosity of the composite films. The accelerated weathering, reduced tensile properties, thermal stability, and rheological properties; however, the percentage crystallinity was increased due to the chain scission of the polymer chains. The combination of ultraviolet irradiation, temperature, and humidity caused by the weathering test marginally reduced the antibacterial properties of the polymer films. [ABSTRACT FROM AUTHOR]

• Waste management assessment on recycling of PP and PLA composites have been studied. • PP/sisal fiber and PLA/sisal fiber composites were recycled for four times. • The tensile strength and modulus of PP composites were not affected by recycling. • PLA based composites show a decrease in mechanical properties after first recycling. • The crystallinity of PLA and PLA composites dramatically increased with recycling. • Water absorption increases with fiber content but decreases with recycling. The effect of recycling on the thermo-mechanical and water absorption behavior of polypropylene (PP)/sisal fiber and polylactic acid (PLA)/sisal fiber composites were studied. The PP-based non-biodegradable composites and PLA-based biodegradable composites were recycled for four times. The effect of recycling was determined by examining the morphology, thermo-mechanical properties, and water absorption behavior and the obtained results were compared. The results showed that the incorporation of sisal fibers in the PP and PLA matrix enhances the tensile modulus and percentage crystallinity of the composites. The tensile strength and modulus of the sisal fiber reinforced PP composites were not affected with recycling. Even though the tensile properties of PLA and PLA/sisal fiber reinforced composites are superior to PP and PP/sisal fiber composites, the PLA-based composites show a dramatic decrease in tensile strength and modulus after the first recycling due to the degradation of the polymer. The thermal stability of the PP/sisal fiber composites was not affected by the repeated recycling process. On the other hand, the PLA-based composites with higher sisal fiber content show a bit lower thermal stability after recycling. The PP-based composites show fluctuations in percentage crystallinity with recycling. On the other hand, a remarkable increase in percentage crystallinity for PLA and PLA-based composites was observed with increasing recycling times. Water diffusion study divulges that the diffusion of water into the polymer composites was reduced with recycling, irrespective of the polymer matrix. [ABSTRACT FROM AUTHOR]