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Glass transitions in polypropylene
Author(s) -
Beck D. L.,
Hiltz A. A.,
Knox J. R.
Publication year - 1963
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.760030407
Subject(s) - tacticity , materials science , polypropylene , amorphous solid , glass transition , thermal expansion , polymer , composite material , polymer science , polymer chemistry , polymerization , crystallography , chemistry
Dilatometric measurements show that both isotactic and atactic polypropylenes have two distinct glass transition temperatures. Because of the two transitions, three values for the cubical coefficient of thermal expansion are necessary to accurately define the volume expansion of polypropylene from −80° to +90°C. A method is outlined for calculating the content of amorphous atactic, amorphous isotactic, and crystalline isotactic polymer in a given polypropylene sample.