Kinetics of free radical bulk polymerization of methyl methacrylate

Abstract

In this work, the free radical bulk polymerization of methyl methacrylate was studied at 22.5°C. Polymerization reactions were initiated by thermal decomposition of 2,2 -azobisisobutyronitrile (AIBN). Full range of conversion up to glassy state was investigated. The reaction temperature was choosen as 22.5°C for comparison with the experimental results of photo-initiated free radical polymerization of methyl methacrylate. The conversion-time dependence in polymerization of methyl methacrylate was investigated and the qualitative behaviour of rate and rate constants was discussed over the whole range of reaction. For the initial stages of polymerization, kt /kp2 and Ctr,m values were evaluated and found to be 303 and 5.6x10-5 respectively. Efficiency of the initiator was also determined and calculated as about 0.47 for a single low conversion value. Number average degree of polymerization, Pn, remained constant at the beginning and at the end of the polymerization reaction.