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Influence of temperature changes on crystallization of an ethylene–propylene random copolymer
Author(s) -
Raimo Maria
Publication year - 2004
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.21125
Subject(s) - copolymer , crystallization , isothermal process , materials science , ethylene , morphology (biology) , kinetics , polymer chemistry , chemical engineering , thermodynamics , composite material , polymer , chemistry , catalysis , organic chemistry , physics , genetics , quantum mechanics , biology , engineering
Unconventional procedures were used to crystallize an ethylene/propylene copolymer (E/P), with the aim of investigating the effect of temperature changes on crystallization kinetics and spherulitic morphology. The solidification process of specimens crystallizing under isothermal conditions was cyclically stopped for a while, by increasing the temperature, and afterward reestablished by cooling at the original temperature. The resulting morphology characterized by rings within spherulites was compared to that obtained by continuous isothermal crystallization. The different temperature dependencies of the thermal expansion coefficients of liquid and solid phases account for the presence of rings within spherulites grown in a temperature field. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2008–2013, 2004