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Effects of transformation phenomena on polymer synthesis
Author(s) -
Pascault JeanPierre
Publication year - 1997
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19971220109
Subject(s) - thermosetting polymer , epoxy , polymer , gel point , polymer chemistry , materials science , diffusion , chemical engineering , molecule , amine gas treating , glass transition , chemistry , organic chemistry , thermodynamics , composite material , physics , engineering
The chemistry and the reaction rates have been related to the phase transitions and transformations occuring during different polymer syntheses. Early cristallization of chain segments disturbs the synthesis of linear segmented polyureas or polyurethanes. The gelation process occuring during the epoxy‐amine network formation does not affect the reaction rate, but after vitrification, this reaction becomes diffusion‐controlled. In the case of modified thermoset a liquid‐liquid transition may induce a fractionation phenomenon which modifies the average functionality of the molecules and the appearance of the gel point.