頁籤選單縮合
題 名 | Crystallization and Melting Behaviors of Poly(trimethylene terephthalate) |
---|---|
作 者 | Huang,Jieh-ming; Ju,Ming-yih; Chu,Peter P.; Chang,Feng-chih; | 書刊名 | Journal of Polymer Research |
卷 期 | 6:4 1999.10[民88.10] |
頁 次 | 頁259-266 |
分類號 | 346.84 |
關鍵詞 | Poly(trimethylene terephthalate); Melting behavior; Crystallization; Differential scanning calorimetry; Double melting endotherms; |
語 文 | 英文(English) |
英文摘要 | 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□) for a given time, the isothermally crystallized PTT exhibits two melting endotherms, which is similar to that of PET and PBT. At higher crystallization temperature (T□=210℃), the low-temperature endotherm is related to the melting of the original crystals, while the hgih-temperature endotherm is associated with the melting of crystals recrystallized during the heating. 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℃/min) or a high heating rate (40℃/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□□, of the PTT. This phenomenon suggests that the mobility of the PTT molecules decreases after the annealing process. The equilibrium melting temperature (T□□) determined by the Hoffman-Weeks polt is 248℃. |
本系統中英文摘要資訊取自各篇刊載內容。