کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5190901 | 1381220 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The crystal structure of poly(2,6-naphthalenebenzobisthiazole)
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The crystal structure of poly(2,6-naphthalenebenzobisthiazole) (Naph-2,6-PBT) was studied using X-ray and molecular modeling methods. The X-ray pattern of the annealed Naph-2,6-PBT fiber showed several Bragg reflections as well as streaks along the layer lines indicating that the registry between adjacent chains exists in the crystal with a great deal of axial disorder. Disordered structure in the crystal was fitted into the triclinic unit cell with the unit cell parameters of a=6.78Â Ã
, b=3.46Â Ã
, c=14.61Â Ã
, α=88.0°, β=114.7°, and γ=94.8° with PI¯ space group. The calculated density, 1.68 g/cm3 was comparable with the observed density, 1.56 g/cm3. The Îc/c (staggering ratio) representing the registry between the adjacent chains in the ac plane was â0.19, which is in good agreement with the energy calculation although another local energy minimum was found at Îc/c=0.31. The disordered structure in Naph-2,6-PBT was probably due to the discrete axial shift between Îc/c=0.31 and â0.19 in the ac plane. The LALS refinement showed that the naphthalene group was rotated by 9 (±3)° from the ac plane on the projected structure along the chain axis with a torsion angle between the naphthalene and benzobisthiazole rings of 23°.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 15, 11 July 2005, Pages 5630-5636
Journal: Polymer - Volume 46, Issue 15, 11 July 2005, Pages 5630-5636
نویسندگان
Soo-Young Park, Sang-Cheol Moon, Thuy D. Dang, N. Venkatasubramanian, Jar-wha Lee, B.L. Farmer,