کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5190243 | 1381201 | 2006 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
FTIR spectra of pure helical crystalline phases of syndiotactic polystyrene
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
By quantitative evaluation of the spectral changes associated with guest removal from clathrate films as well as by infrared dichroism measurements on uniaxially oriented films, three infrared absorbance peaks (at 1379, 1154 and 841 cmâ1) prevailingly associated with the amorphous phase have been located for syndiotactic polystyrene (s-PS) samples with helical crystalline phases. A detailed study relative to the infrared peaks in the wavenumber range 870-820 cmâ1, corresponding to phenyl C-H out-of-plane bending, has shown that the 841 cmâ1 peak is fully associated with conformationally disordered sequences only for samples including trans-planar crystalline phases (α and β) but not for samples including helical crystalline phases (γ, δ and clathrates). This result has been rationalized on the basis of different intermolecular interactions between phenyl rings, occurring for trans-planar and helical s-PS crystalline phases. Moreover, a preparation procedure leading to fully unoriented films has been described for helical semicrystalline films, which generally present different kinds of uniplanar orientation. FTIR spectra of these fully unoriented semicrystalline films, by subtracting out the amorphous phase contribution with a procedure based on the 1379 cmâ1 peak, have allowed a straightforward isolation of the spectra of the helical s-PS crystalline phases and the quantitative determination of the amorphous content.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 1, 3 January 2006, Pages 234-242
Journal: Polymer - Volume 47, Issue 1, 3 January 2006, Pages 234-242
نویسندگان
Alexandra R. Albunia, Pellegrino Musto, Gaetano Guerra,