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Free radical bulk polymerization in cylindrical molds
Author(s) -
Fontes C. E.,
Lage P. L. C.,
Pinto J. C.
Publication year - 2002
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11038
Subject(s) - dispersity , materials science , polymer , monomer , diffusion , polymerization , kinetics , styrene , kinetic energy , polymer chemistry , radical polymerization , thermodynamics , chemical engineering , copolymer , composite material , physics , quantum mechanics , engineering
Bulk styrene homopolymerization in cylindrical molds was studied in order to simulate the reactive injection process when the reaction kinetics was much slower than the filling process. Mathematical models were built and implemented, allowing the analysis of certain kinetic phenomena, such as the gel‐effect, and the relevance of natural convection. Based on a detailed kinetic mechanism, the polymer properties (average molecular weight and polydispersity) and monomer conversion were calculated as functions of spatial coordinates and time. The results obtained show that polymer properties and monomer conversion may be very heterogeneous inside the cylindrical mold, although insensitive to variations of the diffusion coefficient, so that defects are expected to appear as a consequence of the heterogeneity of polymer properties inside the mold. Experiments confirmed the simulation results. Simulations indicate that heterogeneities may be expected to increase when the reaction rates are one order of magnitude higher, as in acrylic acid polymerizations.