Accession Number : ADA310240

Title :   Radical Polymerization of Styrene in the Presence of Nitroxyl Radicals. Experiments and Simulations.

Descriptive Note : Technical rept.,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF CHEMISTRY

Personal Author(s) : Greszta, Dorota ; Matyjaszewski, Krzysztof ; Priddy, Duane

PDF Url : ADA310240

Report Date : 12 JUN 1996

Pagination or Media Count : 5

Abstract : Polymerization of styrene in the presence of a stable radical TEMPO has been simulated using a Predici simulations package. Based on the experimental data, a kinetic model for the TEMPO-moderated polymerization of styrene has been proposed. It was shown that in order to properly simulate the experimental data, in addition to the reversible cleavage of the TEMPO-polymeric radical adduct, it is necessary to include thermal self-initiation, transfer and irreversible decomposition of intermediate alkoxyamines in the polymerization model. This model, combined with the experimental data and literature values of the rate constants of propagation (kp), termination (kt), transfer (ktrm), and alkoxyamines decomposition (kdecomp), was then employed to estimate kinetic and thermodynamic parameters of the exchange between dormant and active species. The equilibrium constant K was estimated to be around 1.10(exp -10) mol/L, the deactivation rate constant kd - 3.10(exp 7) mol-1Ls-1 and the activation rate constant ka= 3.10(exp -3)mol-1Ls-1 for bulk styrene polymerization at 120 deg C.

Descriptors :   *POLYMERIZATION, *STYRENES, *NITRO RADICALS, HEAT TRANSFER, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, ACTIVATION, EXCHANGE REACTIONS, REACTION KINETICS, MOLECULAR WEIGHT, AMINES, THERMAL ANALYSIS, REVERSIBLE, DECOMPOSITION, CHEMICAL EQUILIBRIUM, CONCENTRATION(CHEMISTRY), IRREVERSIBLE PROCESSES, DEACTIVATION, ALKOXY RADICALS, PIPERIDINES.

Subject Categories : Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE