Effect of crosslinking monomers on the performance of electron beam-induced biodegradable Bionolle-rubber blends

To find out the better crosslinking monomer for vulcanization of natural ru bber under electron beam (EB) radiation, the dry rubber was masticated with different polyfunctional monomers like TMPTA, NVP, and ethylene glycol dia crylate of different numbers of CH2- CH2-O group, such as 1G, 3G, 7G, and 1 0G. The masticated films were irradiated with different doses under EB at 1 0 kGy/pass. The highest tensile strength (25 MPa) of the rubber was observe d in the presence of TMPTA (3phr) at 150 kGy dose. The gel content of the r ubber increased with an increase of dose. Bionolle was mixed with the masti cated rubber containing 3 phr TMPTA at different proportions; films of thes e blends along with Bionolle were irradiated under EB with different doses. The concentration of rubber in Bionolle and radiation dose were optimized. The elastomer with 5% masticated showed the highest tensile strength (62 M Pa). The gel content of the blends was found to increase with an increase o f radiation dose as well as rubber concentration in Bionolle. The elastomer s or blends were found to possess good thermal properties. The elastomers e xhibited a much lower loss of tensile strength due to the thermal aging com pared with pure Bionolle. The elastomers sustained their original shape for 300 min at 180 degreesC, whereas Bionolle sustained its shape for only 3 m in at 120 degreesC under the same load (50 g). Among all the elastomers, 5% rubber containing elastomer was found to be better in all respects. It was observed from scanning electron microscopy and differential scanning calor imetry studies that 5% rubber is well mixed with Bionolle. (C) 2001 John Wi ley & Sons, Inc.