Influence of electron beam irradiation on the mechanical properties and crosslinking of fluorocarbon elastomer

The influence of electron beam irradiation on the mechanical and dynamic me chanical properties, gel fraction and crosslink density of terpolymeric flu orocarbon rubber has been investigated in this paper. An attempt has been m ade to correlate the structure of the irradiated rubber with the properties . With increase in radiation dose, an increase in degree of crosslinking re sults which leads to increase in modulus and Tg with a corresponding decrea se in elongation at break, set and tan delta. The effect of multifunctional monomer is realized only at relatively higher level of trimethylolpropane triacrylate (TMPTA), where improvement in strength and failure properties i s observed. The dynamic storage modulus at 50 degrees C is higher and loss tangent becomes lower. Among the various polyfunctional monomers tripropyle neglycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA) and tet ramethylolmethane tetracrylate (TMMT), the mechanical properties and the de gree of crosslinking are lowest for systems based on TPGDA. MgO used in the formulation leads to the improvement in mechanical properties. Increase in the crosslink density is in line with reduced loss tangent and increased s torage modulus for the MgO filled rubber vulcanizate. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.