BAMBOO FIBER-REINFORCED POLYPROPYLENE COMPOSITES - CRYSTALLIZATION AND INTERFACIAL MORPHOLOGY

Bamboo fiber-reinforced polypropylene (PP) composites were prepared. P P and two maleated polypropylenes( s-MAPP and m-MAPP) were used as mat rices. Crystallization and interfacial morphology were studied by usin g differential scanning calorimetry (DSC), wide angle X-ray diffractio n (WAXD), and optical microscopy. It has been shown that the addition of bamboo fiber to any of the three polymers causes an increase in the overall crystallization rate. A considerable amount of beta-form crys tallinity was produced in the PP, s-MAPP, and m-MAPP by mixing with ba mboo fiber; and all the bamboo fiber-filled samples contain both the a lpha- and the beta-forms. The relative amount of the beta-form in the samples was calculated from WAXD data by the K value. There is no beta -form observed in the pure PP, s-MAPP, and m-MAPP. Bamboo fiber acted as both a reinforcement and a beta-nucleator. The nucleation density o f both s-MAPP and m-MAPP at the fiber surface is remarkably higher tha n that of PP because an improved interfacial adhesion is reached in th e case of s-MAPP and m-MAPP as matrices. The transcrystalline growth o f s-MAPP and m-MAPP on the bamboo fiber surface was observed under opt ical microscope with crossed polars. (C) 1997 John Wiley & Sons, Inc.