Preparation of compounded rubber from natural rubber grafted with vinyl acetate

Abstract

Rubber band production using sheet and block rubber is carried out with many stages of additive mixing. This research aims to improve the production at low cost and shorter time by using concentrated latex and, at the same time, to improve mechanical properties of rubber by grafting with vinyl acetate. Compounded rubber was prepared by ball mill and the degree of crosslink of rubber and vinyl acetate was investigated by soxhlet extraction technique to remove homopolymer using hexane and methyl ethyl ketone, respectively as solvents. It was found that the degree of crosslink was more than 97%. The grafting of vinyl acetate was studied by ATR-FTIR. From the study, the carbonyl group of vinyl acetate appeared at wave number 1649 cm -1, which indicated the grafting of vinyl acetate. The mechanical properties of vulcanized rubber were monitored by tensile strength, elongation at break, modulus, hardness, rebound resilience and aging properties. The effects of vinyl acetate content, types of initiator and mixing time were studied. The optimum condition of compounded rubber with the best mechanical properties were 4 phr of vinyl acetate, 1 hour of mixing time, and tert-butylhydroperoxide as an initiator. The mechanical properties of compounded rubber were 19.28 MPa tensile strength, 2326.33% elongation at break, 1.223 Mpa modulus, 42 Shore A hardness, 84.08% rebound resilience. Moreover, it was found that the aging properties of compounded rubber was in the range of various applications.