Study of the effect of structure of ethylene-propylene-diene-graft-polystyrene copolymers on their physical properties

Ethylene-propylene-diene-graft-polystyrene (EPDM-g-PS) copolymers were synthesized by grafting styrene monomer onto EPDM copolymer. For these purposes three different types of EPDM copolymers which differ in concentration of double bonds and ethylene were used. Synthesis was carried out in toluene solution using dibenzoyl peroxide as initiator at 90 °C. Variation of polymerisation time was used to obtain different graft lengths. Graft density was modified by the addition of triallylcyanurate, TAC coagent. Graft copolymers were extracted from the mixture of polymers that were obtained by polymerisation. The graft copolymers were identified and characterized. Identification of synthesized graft copolymers as well as presence of TAC was followed by FTIR spectroscopy. The chain structure of the graft copolymers was investigated by glass transition temperature, by molecular masses, Mn¯,Mw¯ and by intrinsic viscosity. The results show significant dependence of glass transition temperature and of weight average molecular masses on polymer chain composition.