A study of multisubstituted chain transfer agents on the kinetics of homopolymerisation of methylmethacrylate .

A continuation to a previous study of monosubstiuted transfer agents, carried out by the same author, this investigation had been done. It has been found that multisubstituted chain transfer agents, such as tricholoro acetic acid, Di and Tribromo acetic acid, have played a significant role in the reduction of both the rate of polymerization and the molecular weights obtained of the homopolymers of methylmethacrylate, other vinylic monomers such as styrene, showed the same behavior, though they differ in their chemical nature especially that involved their stability due to the resonance effect . Key word : Free radical-macromers INTRODUCTION 2-Mercapto thyroxinthone (TX-SH) as a chain transfer agent {CTA}was used in the homopolymerisation of both methylmethacrylate{MMA},styrene {St.}, by inserting isobisazobutyronitrile {AIBN} as initiator at 70C producing a polymer holding TX groups (1) . Thioketones were used for the same purpose (2) . Though the thiols are considerably active compounds as CTA, but they have some disadvantages, such as bas smell, color and toxicity (3) .