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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]

Composites composed of polylactide (PLA), modified PLA and woven flax fiber textiles (flax weave style of 2 × 2 twill and 4 × 4 hopsack) were produced by hot press technique. Two structurally different additives were used to modify PLA. The dispersion of the flax in the composites was studied by scanning electron microscopy and computed microtomography system (µCT). The PLA composites were subjected to water absorption and instrumented falling weight impact tests. The thermomechanical and creep properties of the composites were determined using thermogravimetric analysis, dynamic-mechanical thermal analysis and short-time creep tests. It was found that the modified PLA and its composite increased the impact resistance compared with the unmodified PLA. Incorporation of flax decreased resistance to thermal degradation and increased water uptake. The impact energy and stiffness value of PLA/flax composites were markedly higher than that of PLA but reflect the effects of composite structures and flax content. The storage modulus master curves were constructed by applying the time–temperature superposition principle. From the master curve data, the effect of modified PLA on the storage modulus was more pronounced in the low frequency range. [ABSTRACT FROM PUBLISHER]