THE EFFECTS OF MULTIFUNCTIONAL ADDITIVE AND EPOXIDATION IN SILICA FILLED NATURAL-RUBBER COMPOUNDS

The effects of multifunctional additive (MFA) and epoxidation on physi cal properties and curing characteristics of silica filled natural rub ber compounds have been studied Three different types of natural rubbe r, SMR L, ENR 25 and ENR 50 having 0, 25 and 50 mol % of epoxidation a nd semi-efficient vulcanization were used. The cure time, (t(90)) and scorch time, (t(5)) of all rubbers decreases with increasing MFA level . At similar MFA level, ENR 50 possessed the shortest scorch and cure times followed by ENR 25 and SMR L vulcanizates. Compared to the contr ol compound (without MFA), the physical properties in all rubbers have been enhanced by the addition of MFA. However at similar MFA level, t he physical properties viz. tensile and tear strengths of SMR L vulcan izates is highest followed by ENR 25 and ENR 50 vulcanizates. (C) 1998 Elsevier Science Ltd. All rights reserved.