Cellulose Microfibrils Filler Contributes to Thermal Stability and Morphology of Bioplastics from Sorghum-Based

Abstract

This research aimed to examine the effect of cellulose microfibrils (CMF) as a filler to thermal characteristics and morphology of bioplastic. Sorghum starch and chitosan, of which 63 micron particle size, were varied by starch to chitosan ratio (g/g) of 10:0; 9.5:0.5; 8.5:1.5; 7.5:2.5; 6,5:3.5; and 5.5:4.5 respectively. About 1 gr (10% on a weight basis) of glycerol, as a plasticizer, was appended to the mixture. The addition of CMF was done to the mixture, and its concentration was varied 0, 1, 2, and 3% (w/w). The combination of 8.5 g sorghum starch and 1.5 g chitosan gave the best results. It revealed the enhance of the thermal characteristic of bioplastic due to the increase of the filler — this phenomenon expressed by glass transition, crystallinity, and melting temperature of bioplastic. The SEM analysis on the morphology structure of the bioplastic surface showed that the addition of the filler will contribute to dense of bioplastic structure.