Abstract:
Polymer blends between polypropylene (PP) starches and modified starches were prepared in this research. Modified starches were prepared from the reaction between the starch and maleic anhydride using sodium hydroxide as a catalyst and water as a solvent at 50 ํC. While glutinous starch was modified by 35% by mole for 30 minutes, cassava starch was modified by 25% by mole for 2 hours. PP, unmodified and modified starches were then mixed and compressed to from polymer blend sheets at 180 ํC for 5 minutes. The amounts of unmodified starch starche were varied from 10, 20, 30 40 and 50% w/w. The amounts of unmodified starches were varied from 5, 10, 15 and 20 phr. From mechanical tests including tensile, flexural and impact properties, it was found that PP/starch/modified starch blends exhibited higher % moisture absorption and better biodegradability than those of all starch/PP blends prepared without modified starch. While cassava starch blends exhibited better mechanical properties than glutinous starch blends, the latter showed better moisture absorption and biodegradability than the former. The results suggested that polymer blends prepared from PP and cassava starch at weight ratio of 90:10 and modified cassava starch 10 phr and from PP and glutinous starch at weight ration of 90:10 and modified glutinous starch 10 phr exhibited better overall properties than prepared with other compositions.