کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1232677 1495230 2015 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic and spectroscopic analysis of the conformational transition of poly(vinyl alcohol) by temperature-dependent FTIR
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Thermodynamic and spectroscopic analysis of the conformational transition of poly(vinyl alcohol) by temperature-dependent FTIR
چکیده انگلیسی


• FTIR technique was used to study the trans/gauche translation.
• The structural information was gained by analyzing the differential spectra.
• As the increase of temperature, PVA film took the conformational transition from trans to gauche.

The conformational change of poly(vinyl alcohol) has been studied by Fourier transform infrared spectroscopy at various temperatures in the 4000–400 cm−1 region. The molecular motion and the trans/gauche content are sensitive to the CH, CC stretching modes. FTIR spectra show that the I2920/I2849 decreases from 1.84 to 1.0 with increasing temperature, companying the decrease in I1047/I1095 from 0.78 to 0.58, implying the conformational transition from trans to gauche in alkyl chain. Based on the van’t Hoff relation, the enthalpies and entropies have been calculated in different temperatures, which are 4.61 kJ mol−1 and 15.23 J mol−1 K−1, respectively, in the region of 80–140 °C. From the CO stretching mode and OH band, it can be concluded that the intermolecular hydrogen bonds decrease owing to elevating temperature, which leads to more gauche conformers.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 139, 15 March 2015, Pages 37–42
نویسندگان
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