標題: Conformational changes and molecular motion of poly(ethylene terephthalate) annealed above glass transition temperature
作者: Huang, JM
Chu, PP
Chang, FC
應用化學系
Department of Applied Chemistry
關鍵字: poly(ethylene terephthalate);solid-state NMR;crystallinity
公開日期: 1-Mar-2000
摘要: Conformational conversion and molecular dynamics of the amorphous poly(ethylene terephthalate) (PET) annealed above T-g were investigated by C-13 high-resolution solid-state NMR and differential scanning calorimetry (DSC). Rapid increase in the PET trans content and crystallinity were observed near the onset crystallization temperature (congruent to 120 degrees C). By comparing both changes in conformation and crystallinity during thermal annealing, we found that the trans conformer increases continuously while the degree of crystallinity levels off during the later stage of annealing. The H-1 spin-lattice relaxation time in the rotating frame (T-1 rho(H)) correlates linearly with PET crystallinity but less well with the trans content. A three-domain model containing crystalline (all trans), constrained noncrystalline (trans rich) and amorphous (gauche rich) phases satisfactorily explains the relationship among the PET conformation, crystallinity and annealing conditions. This study complements the prior study of molecular motion by T-1 rho(C), and illustrates the importance of the trans conformer to induce PET crystallization. (C) 1999 Elsevier Science Ltd. All rights reserved.
URI: http://dx.doi.org/10.1016/S0032-3861(99)00329-8
http://hdl.handle.net/11536/30673
ISSN: 0032-3861
DOI: 10.1016/S0032-3861(99)00329-8
期刊: POLYMER
Volume: 41
Issue: 5
起始頁: 1741
結束頁: 1748
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