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Isothermal and nonisothermal crystallization of poly(aryl ether ketone ketone) with all‐ para phenylene linkage
Author(s) -
Wang Jiku,
Yang Xiaoniu,
Li Gao,
Zhou Enle
Publication year - 2001
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.2204
Subject(s) - crystallization , spherulite (polymer physics) , materials science , differential scanning calorimetry , isothermal process , phenylene , polybutene , crystallography , transmission electron microscopy , polymer chemistry , thermodynamics , composite material , chemistry , polymer , physics , nanotechnology
Isothermal and nonisothermal crystallization behavior for PEKK(T) was studied using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and electron diffraction (ED). In the isothermal crystallization process, the Avrami parameters obtained were n = 2.33–2.69, which shows crystal growth of two‐dimensional extensions consistent with our observations by TEM. The lamellar thickness increases with the crystallization temperature of PEKK(T) crystallized isothermally from the melt. However, for the nonisothermal crystallization of PEKK(T), the results from the modified Avrami analysis show two different crystallization processes. Avrami exponents n 1 = 3.61–5.30, obtained from the primary crystallization process, are much bigger than are the secondary n 2 = 2.26–3.04 and confirmed by the observation of the spherulite morphology. PEKK(T) crystallized isothermally from the melt possesses the same crystal structure (Form I) as that from nonisothermal melt crystallization. The results from TEM observation show that the spherulite radius decreases with an increasing cooling rate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3431–3438, 2001