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In the present investigation, the effects of fiber content (20, 30 and 40 wt%) and annealing heat treatment on the thermal properties of the biocomposite material formed by an isotactic polypropylene polymeric matrix (iPP) reinforced with short bamboo fibers (PP/BF) were studied. The coupling agent was iPP with grafting of maleic anhydride molecules (MAPP). The Differential Scanning Calorimetry (DSC) technique was used to determine the melting temperature (Tm), crystallization temperature (Tc), and degree of crystallinity (Xc) of the biocomposites. The melting temperature of pure PP was not significantly affected by the presence of bamboo fibers. However, the degree of crystallinity of PP increased with fiber content. The annealing heat treatment caused an increase in the Tm of pure PP and PP/BF. The composite with 20 wt% fiber content (PP/20F) annealed achieved the highest Xc (37,47 %). The Tc of polypropylene increased with the presence of fibers, and the PP/20F composite reached the highest value (115 °C). Also, the study of the Tm of the biocomposites in amorphous state was carried out, and it was observed that the sample with a fiber content of 30 wt% presented an endothermic peak at a temperature of approximately 168 °C. [ABSTRACT FROM AUTHOR]

In the present investigation, the tensile mechanical properties of the isotactic polypropylene (PP) biocomposite material reinforced with randomly oriented short bamboo fiber bundles were determined. Samples of the material with different reinforcement contents (20, 30 and 40%) were prepared, using polypropylene with grafts of maleic anhydride molecules (MAPP) as coupling agent. A group of these samples were subjected to an accelerated thermal aging treatment to evaluate the effect of said treatment on the tensile properties of the biocomposite. Tensile tests were carried out at different deformation rates (10 and 50 mm/min) and an increase in tensile strength (29 to 45 MPa) and elastic modulus (1 to 3 GPa) of the PP with the fiber content was obtained. For different stretching speeds, better resistance at high speeds was obtained. Thermal aging for 24 hours at 100 °C increased the resistance of pure PP. For the biocomposites, a low resistance was obtained in the samples aged in greater time (98 °C, 10 days). Through scanning electron microscopy, a microstructural characterization was carried out that allowed explaining the improvement of the resistance of the fiber reinforced PP, and in some cases, the loss of resistance due to heat treatment. [ABSTRACT FROM AUTHOR]