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Crystallization kinetics of ultra high‐molecular weight polyethylene in liquid paraffin during solid–liquid thermally induced phase separation process
Author(s) -
Zhang ChunFang,
Bai YunXiang,
Gu Jin,
Sun YuPing
Publication year - 2011
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.34429
Subject(s) - crystallization , avrami equation , materials science , differential scanning calorimetry , arrhenius equation , isothermal process , crystallinity , thermodynamics , polyethylene , phase (matter) , linear low density polyethylene , activation energy , polymer chemistry , crystallization of polymers , chemical engineering , chemistry , composite material , organic chemistry , physics , engineering
Abstract The crystallization behaviors of ultra high‐molecular weight polyethylene (UHMWPE) in liquid paraffin under isothermal and nonisothermal conditions were studied by differential scanning calorimetry during the solid–liquid thermally induced phase separation (TIPS) process. For isothermal crystallization, the development of relative crystallinity with the crystallization time is analyzed by the Avrami equation with the exponent n = 2.7. The relatively high content of secondary crystallization at higher crystallization temperature can be obtained due to the high mobility of UHMWPE chains. For nonisothermal crystallization studies, the Avrami theory modified by Jeziorny is used, and the result is found that the Avrami exponent n is variable around 5 and decreases slightly as the cooling rate decreases. In addition, the extent of secondary crystallization increases with increasing cooling rate. The calculated activation energies are 881 kJ/mol for isothermal crystallization obtained from the Arrhenius equation and 462 kJ/mol for nonisothermal crystallization from the Kissinger equation, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.