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Crystallization of polymer melts under fast cooling. II. High‐purity iPP
Author(s) -
Piccarolo S.,
Saiu M.,
Brucato V.,
Titomanlio G.
Publication year - 1992
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.1992.070460409
Subject(s) - crystallization , materials science , polymer , chemical engineering , crystallization of polymers , polymer chemistry , polymer science , composite material , engineering
Samples of a high‐purity isotactic polypropylene (iPP) were quenched from the melt so as to monitor cooling history. A continuous variation of morphology and crystal structure was obtained with cooling rate. This is discussed in relation to sample thermal history evidencing that cooling history relevant to quenched samples is in the neighborhood of 90°C. In particular the samples are essentially mesomorphic when at this temperature cooling rates larger than 80°C/s were adopted, while below a few tens of °C/s only α‐monocline form is obtained. Densities of quenched samples were compared with predictions of an isokinetic extrapolation of Avrami model of polymer crystallization kinetics.