Radiation vulcanization of natural rubber latex by Caesium-137 source

Abstract

Radiation vulcanized natural rubber latex is a rubber latex vulcanized by using ionizing radiation such as gamma radiation or electron beam. Gamma radiation is preferred over electron beam due to its higher penetration power, and Cobalt-60 is commonly used as a gamma radiation source for the irradiation process. Caesium-137 is another source for gamma radiation but it is not commonly used for RVNRL preparation despite its longer half-life. Caesium-137 retains its source activity much longer than Cobalt-60 and a Caesium-137 based irradiation facility would require less replenishment compares with the one with Cobalt-60. One of the reasons preventing the application of Caesium-137 for RVNRL preparation is its lower gamma radiation energy. This study aimed to analyze RVNRL prepared by using Caesium-137 source from a gamma cell and to compare its tensile properties with RVNRL prepared by using Cobalt-60 source. Results showed evidence of radiation induced crosslinking in RVNRL prepared by Caesium-137 source. At radiation dose of 12 kGy, the tensile properties of RVNRL prepared by Caesium-137 source is comparable to those by Cobalt-60. At radiation dose below 12 kGy, the effectiveness of Caesium-137 in radiation vulcanization is found to be better than that of Cobalt-60.