Thermokinetic parameter estimation of RAFT solution polymerization of dodecyl methacrylate by reaction calorimetry

Abstract

The kinetics of RAFT polymerization of a dodecyl methacrylate controlled by a trithiocarbonate as a chain transfer agent (CTA) are studied by measuring the thermal profile in an RC1-RTCal reaction calorimeter. Contrary to classical methods such as electron spin resonance spectroscopy, the equilibrium constants related to the addition and fragmentation steps are estimated for a high degree of polymerization. The estimation method consists of a comparison between the measured thermal profiles and those built from models reflecting the instantaneous balances of mass and energy. The influence of the concentration of the transfer agent on the characteristics of the polymer (molar mass and dispersity) was also studied at different reaction temperatures. An increase in the concentration of CTA decreases the viscosity of the medium due to a more homogeneous distribution of the small sizes of the polymers. The influence of reaction temperature on the characteristics of polymers is reduced in the presence of CTA.