US EPA

6657042 

Journal Article 

Modeling stable free-radical polymerization 

Zhu, SP; , 

1999 

Yes 

Journal of Polymer Science. Part B, Polymer Physics
ISSN: 0887-6266 

WILEY 

HOBOKEN 

2692-2704 

WOS:000082336100013 

A kinetic model has been developed for stable free-radical polymerization (SFRP) processes by using the method of moments. This model predicts monomer conversion, number-average molecular weight, and polydispersity of molecular weight distribution. The effects of the concentrations of initiator, stable radical, and monomer, as well as the rate constants of initiation, propagation, termination, transfer, and the equilibrium constant between active and dormant species, are systematically investigated by using this model. It is shown that the ideal living-radical polymerization having a linear relationship between number-average molecular weight and conversion and a polydispersity close to unity is the result of fast initiation, slow propagation, absence of radical termination, and a high level of dormant species. Increasing stable radical concentration helps to reduce polydispersity but also decreases polymerization rate. Thermal initiation significantly broadens molecular weight distribution. Without the formation of dormant species, the model predicts a conventional free-radical polymerization. (C) 1999 John Wiley & Sons, Inc.