Effect of unmodified and modified sago starch on properties of (sago starch)/silica/PVA plastic films

Sago starch was modified by crosslinking with sodium trimetaphosphate (STMP). Different formulations of films were prepared by a blending process and a casting method. A suitable plasticizer was added to the blend. Mechanical properties of plastic films with unmodified and modified sago starch were compared. From the results obtained, films with modified sago starch had better compatibility and interaction with polyvinyl alcohol than unmodified sago starch films. Thus, the tensile strength of modified films was higher, but lower in elongation at break than unmodified sago starch plastic films. Films with modified sago starch also showed lower water absorption, water vapor transmission, and degradation than unmodified sago starch plastic films. Chosen were 1 wt% and 2 wt% of silica as the optimum formulation that produced the best tensile properties for modified and unmodified sago starch plastic films. J. VINYL ADDIT. TECHNOL., 20:185–192, 2014. © 2014 Society of Plastics Engineers