کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5186577 | 1381107 | 2006 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Variations of regular conformation structures in melt of syndiotactic polypropylene
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Regular structures in polymer melt play important roles during crystallization and subsequently influence performances of polymer materials. In the present work, differential scanning calorimetry (DSC) and variable temperature Fourier transform infrared spectroscopy (VT-FTIR) were used to characterize the variations of regular structures in melt of syndiotactic polypropylene (sPP) during heating. It was found that during heating, the structural transition in sPP melt undergoes four stages: (1) destruction of long regular structures; (2) formation of short regular structures; (3) transition from short regular structures to isotropic state; and (4) isotropic state. These regular structures in sPP melt have distinct memory effects on the crystallization behaviors. By using Flory's RIS model, it was found that in final isotropic state, the most common conformers are ttgg and tttt, corresponding to helical and planar-zigzag conformations, respectively. These findings are helpful to deeply understand the essence of structures in sPP melt and microstructure variations during melting.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 22, 18 October 2006, Pages 7813-7820
Journal: Polymer - Volume 47, Issue 22, 18 October 2006, Pages 7813-7820
نویسندگان
Chunxiao Zheng, Xiuqin Zhang, Xia Dong, Ying Zhao, Zhigang Wang, Shannong Zhu, Duanfu Xu, Dujin Wang,