Effects of interfacial modification and fiber content on physical properties of sisal fiber/polypropylene composites

Sisal fiber (SF)/polypropylene (PP) composites were prepared at fiber content of 10, 20, and 30 wt.% and their mechanical, thermal, morphological, and water absorption properties were characterized. The effects of fiber treatment (alkalization and heat treatment) and adding a compatibilizer (maleic anhydride grafted polypropylene, MAPP) on the properties of the PP composites were comparatively studied. The fiber treatment and adding MAPP led to an improvement of mechanical properties, cellulose decomposition temperature, and water resistance of the PP composites. SEM micrographs revealed that the interfacial modification enhanced the interfacial adhesion between the fiber and the PP matrix. Alkalization and heat treatment provided comparable enhancement in the mechanical properties of the sisal fiber/PP composites. Adding MAPP showed the most effective improvement of the mechanical properties of the PP composites. With increasing fiber content, tensile strength and modulus of the PP composites increased but impact strength and elongation at break decreased. Water absorption of PP composites also increased with fiber content.