Effects of modifications of bamboo cellulose fibers on the improved mechanical properties of cellulose reinforced poly(lactic acid) composites

Three kinds of modifications, alkali soaking or silane coupling cellulose and maleic anhydride grafting poly(l-lactic acid), were applied in the preparation of cellulose/poly(l-lactic acid) composites. The effects of treatments of the cellulosic fibers on the mechanical properties of cellulose/poly(l-lactic acid) composites were comparatively investigated. The results demonstrated that the alkali soaking provided the composites with highest strength and Young's modulus, increased by 28.6% and 34.6%, respectively, than untreated samples. The highest impact toughness and elongation were achieved by silane agent pretreatment, which were 115% and 62% higher than those of poly(l-lactic acid) reinforced with virgin bamboo cellulosic fibers. Maleic anhydride grafting had moderate effects on both the stiffness and ductility, exhibiting best over-all properties. From the scanning electron microscopy observations and Fourier transform infrared spectrum analysis, it was found that the interfacial interactions between the filler and matrix were improved after all the modifications mentioned.