Chain length dependent termination for nonisothermal free radical polymerization

An attempt is made to model nonisothermal free radical polymerizations considering chain length dependence of the termination rate. In order to test the model, polymerizations of MMA initiated by AIBN at concentration levels of 0.3 and 0.5 wt.%, were investigated with various temperature programming over the range of 50-90°C. The experiments were so designed that the possible shifts of termination mechanism during gel effect could be examined from conversion histories and/or molecular weight development. The temperature changed significantly in the translational diffusion regime. This kind of design also gives a chance of studying the effect of prepolymers without difficulty in mixing polymer and monomer for high conversions. The polymers produced at earlier temperatures provide a range of environments for the terminating macroradicals.