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Poly(hydroxybutyrate-co-hydroxyvalerate)(PHBV) biocomposites containing of sisal fibers and clay particles were prepared by solution casting technique. Silane (Bis(triethoxysilylpropyl)- tetrasulfide) treatment has been used to modify surface of sisal fiber and enhance the properties of related PHBV composites. The mechanical and thermal properties of the PHBV composites were determined in uniaxial tensile, dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC), respectively. The dispersion of the sisal fiber and clay in the PHBV was studied by scanning electron microscopy (SEM). All PHBV based composites were subject to water absorption. It was found that the tensile and storage modulus of PHBV/5 wt.% sisal composites was improved by maximum 7 % and 10 % respectively. Treated silane of sisal fiber at 5 wt.% was found to enhance tensile modulus by 12 % as compared to the neat PHBV. In corporation of 3 wt.% clay in PHBV matrix increased the tensile and storage modulus by 8 % and 16 % respectively, compared to the neat PHBV. Note that this feature was also confirmed by SEM. Moreover, water uptake and the diffusion coefficient of the PHBV composites systems studied was also calculated. [ABSTRACT FROM AUTHOR]

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) biocomposites different sisal, containing with the fiber length of 0.25 and 5 mm, and addition of clay particles were prepared by hot compression technique. Silane (Bis(triethoxysilylpropyl)tetrasulfide) treatment has been used to modify, and thus enhance, the properties of related hybrid composites. All composites were subject to water absorption test. The mechanical properties of hybrid composites, such as tensile stiffness and strength, toughness, and hardness, determined tensile, impact, and hardness tests, respectively. It was found that tensile strength, stiffness, and impact strength of long sisal fiber improved with increasing fiber content. Hardness of short sisal fiber improved with increasing fiber content. Treated Silane of long fibers at 20 wt.% loading was found to enhance the tensile strength fiber by 10% and impact strength by 750% as compared with the neat PHBV. Note that this feature was also confirmed by scanning electron microscopy. Moreover, the hardness and water resistance of the PHBV/sisal composites increased with the addition of clay particles. The diffusion coefficient for the PHBV and hybrid composites systems studied was also calculated. [ABSTRACT FROM PUBLISHER]

• 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]