Accurate control of product properties through the manipulation of transfer agents can be of great benefit to industry in producing targeted polymeric materials. In this work we developed experimental protocols and mathematical models for understanding and characterising semi-batch emulsion polymerization in the presence of a xanthate-based transfer agent. Zero-one kinetics was employed with population balance equations to predict monomer conversion, molecular weight (MWD) and particle size (PSD) distributions in the presence of xanthate-based reversible addition-fragmentation chain transfer (RAFT) agents. The effects of the transfer agent (AR), surfactant, initiator (KPS) and temperature were investigated. Monomer conversion, MWD and PSD were found to strongly affect monomer feed rate.

The polymerization rate (Rp), number average molecular weight (Mn) and particle size () decreased with increasing AR. Rp increased with increase in SDS and KPS, while with increase in temperature, Mn decreased, Rp increased and increased. With semi-batch mode, Mn and increased with monomer flow rate. Initiator concentration has significant effect on PSD with secondary nucleation at high KPS concentrations. The observed growth rate retardation is due to the exit and re-entry of small radicals. Chain extension was achieved in semi-batch mode. The simulations agree with our experiments and the model accurately predict monomer conversion, Mn, MWD and PSD of polymer products. Our findings indicate monomer feed rate for PSD control, and initial concentration and AR feed rate MWD and PSD control in conjunction with the RAFT agent.