Abstract
Graft copolymerization of styrene onto polyisoprene was carried out to explore the possibility for recycling waste rubber into useful materials. Natural rubber (Mn= 266000) converted to the corresponding polymers with lower molecular weight by heating at 300°C under an air or nitrogen atmosphere (air : Mn= 23600, N2 : Mn= 37600), respectively. Further, the radical copolymerization of lower molecular weight polyisoprene (Mn= 9910; 44 mmol per a natural rubber unit) with styrene (44 mmol) was carried out in bulk at 80°C for 2h, in the presence of 2, 2'-azobis (isobutyronitrile) (5 mol%) under the air atmosphere, resulting in giving the corresponding grafted copolymer in 88.6 % yield, the composition of which was 1 / 1.12 ([isoprene unit] / [styrene unit])
