Two-stage crystallization kinetics equation and nonisothermal crystallization analyses for PTEG and filled PTEG
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A novel modified Avrami model considering both primary and secondary crystallization has been presented to extract the kinetic behavior of these two crystallization stages in nonisothermal crystallization process of polymers. Nonisothermal crystallization kinetics of poly(trimethylene terephthalate)–poly(ethylene glycol) segmented copolyesters (PTEG) has been investigated by differential scanning calorimetry. The crystallization rate constants and Avrami exponents at various cooling rates were obtained from the analyses for neat PTEG and multiwalled carbon nanotube (MWNT) filled PTEG. Secondary crystallization displays a lower-dimensional crystal growth compared with primary crystallization and the results of kinetics analyses are consistent with morphology study. The MWNTs introduced into PTEG matrix take the role of effective nucleating agents during composites crystallization and can expedite the process of crystallization of the matrix by providing more nucleation sites to the crystallizing phase.
KeywordsDifferential Scanning Calorimetry Polarize Optical Microscopy Avrami Exponent Nonisothermal Crystallization Secondary Crystallization
The work was supported by a grant of The Hong Kong Polytechnic University (934K) and a grant from The Doctoral Fund of Ministry of Education of China (No. 200802881030).