Effects of post-gamma irradiation on swelling and mechanical properties of gamma vulcanized natural rubber latex (GVNRL) films

Abstract

Gamma vulcanized natural rubber latex (GVNRL) films have shown promising properties for various applications that require less hazardous chemicals used or released during manufacturing and/or utilization. Examples of potential applications include the uses as chemical-free latex gloves in medical or food-related facilities and as stretchable latex covers for food and agricultural products. However, due to possible degradation on swelling and mechanical properties of these films from post-gamma irradiation used for sterilization, thorough investigations are required in order to fully understand their possible changes and/or degradations in properties of interest. As a result, this work investigated on effects of post-gamma irradiation on swelling and mechanical properties of natural rubber latex (NRL) films, which were pre-vulcanized using 12-kGy and 24-kGy gamma irradiation. The properties of interest in this work included tensile modulus at 300% elongation, tensile strength, and elongation at break, as well as other related physical properties such as swelling ratios and crosslink densities. The results showed that, for samples before post-gamma irradiation, the GVNRL films with 24-kGy vulcanizing dose had higher tensile modulus, tensile strength, and crosslink density, but lower elongation at break and swelling ratio, than the films with 12-kGy vulcanizing dose. However, after post-gamma irradiation at the accumulated dose of 24 kGy, the films with 12-kGy vulcanizing dose showed significant improvements in the values of tensile modulus, tensile strength, and crosslink density, whereas the films with 24-kGy vulcanizing dose showed noticeably degradation in these properties. Hence, the overall results suggested that, while higher gamma vulcanizing doses could initially produce NRL films with higher mechanical strength, they were more negatively affected by post-gamma irradiation such that mechanical degradation could be observed.