Radiation effect on the mechanical stability and biodegradability of CPP/Bionolle blend

Abstract

Blends of polypropylene-co-ethylene (CPP) and polybutylene succinate (Bionolle) with polypropylene grafted maleic anhydride (Modic) as a compatibilizer were prepared by melt blending. Irradiation of the resultant polyblend was carried out using an electron beam in air. It was noted that the Modic compatibilizer also appears to act as a protective agent toward radiation degradation. The occurrence of crosslinking in the polyblend was observed, mainly contributed by Bionolle. However the whole process over all blend composition ranges was dominated by degradation. During indoor storage, the mechanical stability of irradiated polyblends was found to be fairly good, particularly compatibilized Bionolle and CPP/Bionolle (27/75). On the other hand, the sample buried in soil showed a drastic reduction in the over all mechanical properties. The extent of biodegradability as estimated from the weight loss increased with increasing Bionolle content. A synergistic effect on the weight loss was shown by compatibilized Bionolle and CPP/Bionolle (25/75). Additionally, even if the sample was no longer strong due to postirradiation degradation, the biodegradability of the polyblend was not much improved. Using a curve fit model the time for complete weight loss was found to be approximately 14, 8, 7, and 12 months for unirradiated and irradiated Bionolle, compatibilized Bionolle, CPP/Bionolle (25/75) and (50/50), respectively.