Estimation of intrinsic rate coefficients in vinyl chloride suspension polymerization

The pre-exponential factor and the activation energy of the intrinsic rate coefficients for propagation, chain transfer to monomer, chain initiation by a Cl radical and termination in the suspension polymerization of vinyl chloride are estimated by regression of experimental data for the monomer conversion, ranging from 3 to 85%, and for the moments of the molecular mass distribution as a function of batch time over the temperature range of 308-338 K and for initiator (tert-butyl peroxyneodecanoate) concentrations from 0.026 to 3.0 wt%, based on the monomer. Termination by combination is the dominant termination mechanism. Cl radicals, formed in the chain transfer to monomer, contribute to the termination by recombination with macroradicals and, hence, attenuate the gel effect. Physically meaningful and statistically significant estimates for the pre-exponential factors and activation energies, 24.9 kJ mol−1 for propagation and 54.3 kJ mol−1 for chain transfer, allow to describe the experimental data over the full range of investigated conditions.