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Chemical kinetics and diffusion in poly(butylene terephthalate) solid‐state polycondensation: Experiments and theory
Author(s) -
Gostoli C.,
Pilati F.,
Sarti G. C.,
Di Giacomo B.
Publication year - 1984
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1984.070290917
Subject(s) - condensation polymer , kinetics , diffusion , chemical reaction , thermodynamics , materials science , polymer , chemical kinetics , thermal , polymer chemistry , chemistry , chemical engineering , organic chemistry , composite material , physics , quantum mechanics , engineering
Postpolymerization was obtained in solid PBT sheets, by annealing in a dry nitrogen stream at 214°C. After different reaction times, the samples were cut into thin slices. The M w profile within the sample was obtained through intrinsic viscosity measurements in a phenol–TCE mixture. At each location inside the sample, the [η] vs. time curve typically shows a maximum, which is rather broad at the midplane and much sharper at the external surface. The phenomenon was mathematically described by accounting for both diffusion and chemical reactions within the slab; five simultaneous chemical reactions have been considered. The observed behavior is found to be essentially due to two competing processes, i.e., the diffusion of the low molecular weight species generated during the polycondensation and the thermal degradation reaction. The model predictions are compared with the experimental data showing a satisfactory agreement.