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Improvement of Physico-Mechanical Properties of Radiation-Vulcanised Natural Rubber Latex Films by Adding Urea

The role of urea as an additive on the physico-mechanical properties of radiation vulcanised natural rubber latex (RVNRL) films was investigated. RVNRL films were prepared by the addition of urea with the concentration range 0–1.0 phr (parts per hundred rubber) and irradiated with various radiation doses (0–20 kGy). The concentration of urea and radiation doses were optimised and found to be 0.5 phr urea and 12 kGy radiation dose. Tensile strength, tear strength and cross-linking density of the rubber films increased with increasing the concentration of urea as well as radiation doses. The tensile and tear strengths of the films enhanced by 39 and 41%, respectively, at the optimum conditions. Elongation at break, permanent set and swelling ratio of the films decreased with increasing urea concentration and radiation doses until they attained approximately constant values.