BIODEGRADABLE PLASTICS BASED ON SWEETPOTATO STARCH/POLYETHYLENE BLENDS

摘要

Biodegradable polymer blends composed of polyethylene and sweetpotato starch were developed in 10, 20, and 50% starch weight compositions. Morphological studies indicate that the starch has an initial granular structure. This structure is maintained after the blending of the materials is achieved. Scanning Electron Microscope (SEM) micrographs indicate that the granules are well dispersed in the matrix of the polyethylene, which indicates good adhesion between the two materials. Dynamic Scanning Calorimetry (DSC) and X-Ray studies indicate that the melting temperature and degree of crystallinity of the polyethylene basically remains constant as the starch content increases. Mechanical testing suggest that modulus increases with starch content, strain decreases with starch content, and ultimate strength remains constant. Thus, concluding that the starch can be added up to 50%, which suggests improved biodegradability without adverse affects of the integrity, of the blend.