کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10609340 | 984569 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Study of the α-relaxation of PVC, EVA and 50/50 EVA70/PVC blend
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Study of the α-relaxation of PVC, EVA and 50/50 EVA70/PVC blend Study of the α-relaxation of PVC, EVA and 50/50 EVA70/PVC blend](/preview/png/10609340.png)
چکیده انگلیسی
The dipole dynamics and α-relaxation behaviour of polyvinyl chloride PVC, poly(ethylene-co-vinyl-acetate) EVA70 and blend of them EVA70/PVC have been investigated by differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS). The differential scanning calorimetry (DSC) thermograms measured on samples show a single glass transition in the analysed temperature range. These three polymers are wholly amorphous and pure PVC and pure EVA70 are miscible in the ratio 1:1. The glass transition temperature Tg decreases significantly with presence of EVA70. Furthermore, the values of apparent activation energies for molecular motions at the α-relaxation and the values of fragility index have also been determined for each sample using Moynihan expression for DSC results and Vogel-Fulcher-Tammann-Hesse (VFTH) form for DRS results. It is shown a large dependence of all the values of these parameters with the content of EVA70. Comparing these three polymers, we found that the more fragile glass forming liquid is the PVC. Fragility decreases drastically with EVA70 content. EVA70 and EVA70/PVC blend exhibit practically the same behaviour. The effect of inter- and intra-molecular interactions on fragility is discussed to explain these variations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Polymer Journal - Volume 41, Issue 5, May 2005, Pages 1152-1158
Journal: European Polymer Journal - Volume 41, Issue 5, May 2005, Pages 1152-1158
نویسندگان
E. Bureau, C. Cabot, S. Marais, J.M. Saiter,