Zin Min Tun, Khin Khin Lay
Abstract: Radiations vulcanization of natural rubber latex (RVNRL) has been developed extensively through various research and development programme. This holds important benefits for rubber industries in Southeast Asia and the Pacific region. Myanmar also has developed an increasing number of rubber plantations and many rubber raw materials are processed to manufacture medical products, household items and industrial mechanical parts. In this paper, the radiation effect on the vulcanization of natural rubber latex and the synergistic effect of urea addition along with n-butyl acrylate (n-BA) sensitizer on the crosslinking density and mechanical properties of RVNRL film for the production of rubber gloves have been investigated. The various concentration of urea (0.1, 0.2, 0.3, 0.4 and 0.5) (phr) was used in the experiment. Tensile strength, elongation at break, modulus at 500 %, swelling ratio, gel content and crosslinking density were determined. Tensile strength and modulus at 500 %, gel content and crosslinking density were found increasing with absorbed dose, as well as the proportion of n-BA concentration in the rubber phase in presence of urea. The radiation dose for better cross-linking of natural rubber latex with six parts per hundred rubber (phr) n-BA was 15 kGy absorbed dose according to the research. The results also show that addition of 0.3 parts per hundred rubber (phr) urea to the latex before irradiation caused the crosslinking density and tensile strength increase respectively. RVNRL is suitable for production of gloves, balloons, baby teats, rubber products for medical and hygienic used and many other dipped products due to the absence of carcinogenic and toxic products. The rubber gloves were produced using the optimum condition of six parts per hundred rubber (phr) of n-BA, 0.3 (phr) of urea and 15 kGy absorbed dose of gamma radiation. In the RVNRL process, radiation energy replaces the use of a sulfur-based process and produces a material that has all properties of the conventional product.
Keywords: Gamma radiation, Natural rubber latex, N-butyl acrylate, Radiation Vulcanization