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

Blends of polypropylene-co-ethylene (CPP) and polybutylene succinate (Biono lle) with polypropylene grafted maleic anhydride (Modic) as a compatibilize r were prepared by melt blending. Irradiation of the resultant polyblend wa s carried out using an electron beam in air. It was noted that the Medic co mpatibilizer also appears to act as a protective agent toward radiation deg radation. The occurrence of crosslinking in the polyblend was observed, mai nly contributed by Bionolle. However the whole process over all blend compo sition ranges was dominated by degradation. During indoor storage, the mech anical stability of irradiated polyblends was found to be fairly good, part icularly compatibilized Bionolle and CPP/Bionolle (27/75). On the other han d, the sample buried in soil showed a drastic reduction in the over all mec hanical properties. The extent of biodegradability as estimated from the we ight loss increased with increasing Bionolle content. A synergistic effect on the weight loss was shown by compatibilized Bionolle and CPP/Bionolle (2 5/75). Additionally, even if the sample was no longer strong due to postirr adiation degradation, the biodegradability of the polyblend was not much im proved. 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 irradiate d Bionolle, compatibilized Bionolle, CPP/Bionolle (25/75) and (50/50), resp ectively. (C) 1999 Elsevier Science Ltd. All rights reserved.