REALIZATION OF POLYPROPYLENE SISAL FIBER COMPOSITES BY REACTIVE EXTRUSION/

Sisal fibers are used for the reinforcement of a polypropylene matrix. The compatibilization between the two materials is assumed through tr eatment of cellulosic fibers with a maleated polypropylene (PP-graft-M A). The influence of different parameters is studied: fibers fraction, washing of raw fibers, chemical treatment of the fibers in a solvent or during extrusion, rate of maleic anhydride in PP-graft-MA and the r ate of PP-graft-MA in the composites. The effects of these parameters are evaluated by determination of the mechanical properties of the com posites (impact strength and breaking stress) and by the quantity of w ater sorbed by the composites. The elimination of pectic substances by washing of the fibers is favorable for the mechanical properties of t he composites and also reduces their water sorption. The grafting of t he fibers by PP-graft-MA enhances both the impact strength and the bre aking stress.