Green Composites Based on Poly (Lactic Acid) and Bamboo Fiber: Flame Retardancy, Thermal, and Mechanical Properties

摘要

A series of green composites composed of polylactic acid (PLA), bamboo fiber and halogen-free flame retardant (ammonium polyphosphate, APP) were prepared. Moreover, the APP was chemically modified with a silane coupling agent, 3-glycidoxypropyltrimethoxysilane to promote its compatibility with PLA. These green composites were prepared by melt-blending and its flame retardancy, thermal, and mechanical properties were investigated. The results reveal that the thermal degradation temperature and char yield of PLA were significantly elevated when modified APP was added. Furthermore, the storage and loss moduli of the composites can be enhanced effectively by the addition of bamboo fibers. This means that the addition of the bamboo fibers can reinforce both the rigidity and toughness of PLA. Moreover, scanning electron microscopy (SEM) analysis revealed that modified APP has better compatibility with PLA and bamboo fiber. According to the UL-94 analysis, the composite with modified APP and bamboo fiber can reach the highest retardant level V-0. These results indicate that modified APP can enhance the thermal resistance and flame retardant properties better than unmodified ones can. Moreover, the bamboo fibers can not only reinforce the mechanical properties of PLA, but also play an important role of synergistic flame retardancy with modified APP.