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Mechanism of low‐profile behavior in single‐phase unsaturated polyester systems
Author(s) -
Pattison Victor A.,
Hindersinn Raymond R.,
Schwartz Willis T.
Publication year - 1975
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.1975.070191109
Subject(s) - shrinkage , polymerization , polyester , materials science , polymer , monomer , phase (matter) , composite material , polymer chemistry , chemical engineering , chemistry , organic chemistry , engineering
The mechanism of the low profile behavior in certain single‐phase polyester systems has been examined. It appears that as polymerization occurs, crosslinked beads (< 1μ) of polymer separate from the bulk solution. As the temperature rises, liquid monomer expands, counteracting polymerization shrinkage. As shrinkage surpasses expansion towards the end of polymerization, stresses are induced in the system. These are relieved internally by a series of micro cracks in the continuous matrix of the polymer rather than, as in ordinary systems, through macroscopic shrinkage of the molded part.