Controlled radical polymerization of styrene utilizing excellent radical capturing ability of diphenyl ditelluride

Summary The radical polymerization of styrene was investigated in the presence of diphenyl ditelluride (DPDTe) under varied conditions. In the polymerization without any radical initiator at higher temperature (125°C), the addition of DPDTe surely decreased the polymer molecular weight (M _n) while the polydispersity (M _w/M _n) was rather broad. The polymerization with benzoyl peroxide (BPO) as the initiator was also uncontrollable to afford polymers with broad M _w/M _n probably due to the redox side reaction of BPO with DPDTe. On the contrary, the precision control of M _n and the initiating end structure could be achieved by the polymerization with 2,2'-azobisisobutyronitrile (AIBN), that is, M _n increased in proportion to the molar ratio of monomer to initiator suggesting the suppression of bimolecular chain termination reactions by the excellent radical capturing ability of DPDTe. Received: 23 June 1999/Revised version: 11 August 1999/Accepted: 16 August 1999