標題: Crystallization and melting behaviors of poly(trimethylene terephthalate)
作者: Huang, JM
Ju, MY
Chu, PP
Chang, FC
應用化學系
Department of Applied Chemistry
關鍵字: poly(trimethylene terephthalate);melting behavior;crystallization;differential scanning calorimetry;double melting endotherms
公開日期: 1-十月-1999
摘要: The crystallization and melting behaviors of poly(trimethylene terephthalate) (PTT) have been studied by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and solid-state NMR. At certain crystallization temperatures (T-c) for a given time, the isothermally crystallized PTT exhibits two melting endotherms, which is similar to that of PBT and PBT. At higher crystallization temperature (T-c = 210 degrees C), the low-temperature endotherm is related to the melting of the original crystals, while the high-temperature endotherm is associated with the melting of crystals recrystallized during the hearing. The peak temperatures of these double-melting endotherms depend on crystallization temperature, crystallization time, and cooling rate from the melt as well as the subsequent heating rate. At a low cooling rate (0.2 degrees C/min) or a high heating rate (40 degrees C/min), these two endotherms tend to coalesce into a single endotherm, which is considered as complete melting without reorganization. WAXD results confirm that only one crystal structure exists in the PTT sample regardless of the crystallization conditions even with the appearance of double melting endotherms. The results of NMR reveal that the annealing treatment increases proton spin lattice relaxation time in the rotation frame, T-1 rho(H), of the PTT. This phenomenon suggests that the mobility of the PTT molecules decreases after the annealing process. The equilibrium melting temperature (T(m)degrees) determined by the Hoffman-Weeks plot is 248 degrees C.
URI: http://hdl.handle.net/11536/31048
ISSN: 1022-9760
期刊: JOURNAL OF POLYMER RESEARCH-TAIWAN
Volume: 6
Issue: 4
起始頁: 259
結束頁: 266
顯示於類別:期刊論文


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