Preparation of modified cassava starch and polypropylene blends

Abstract

This research presents the preparation of biodegradable plastic from polymer blends between modified and unmodified cassava starch with polypropylene (PP). Modified cassava starch can be prepared from the reaction between cassava starch and 25% of maleic anhydride using sodium hydroxide as a catalyst and water as a solvent at 50 ํC and the reaction time of 2 hours. Both modified and unmodified cassava starch were mixed with PP and compressed to form polymer blend sheets at 180 ํC for 5 minutes. The amounts of starch were varied from 0 5 10 15 20 25 30 40 50 60 70 80 90 and 100% w/w. It was found that as the amount of starch was higher than 50%, the blend sheet were brittle so they cannot be processed into test specimens. When the amount of starch was 0-50%, it was found that modified starch/PP blends exhibited higher tensile properties, higher flexural properties, comparable impact strength, higher %moisture absorption and better biodegradability than those of unmodified starch/PP blends.