کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1398459 | 984381 | 2009 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Note on the glass transition temperature of Poly(vinylphenol) Note on the glass transition temperature of Poly(vinylphenol)](/preview/png/1398459.png)
Critical overview of literature data on the glass transition temperature Tg of poly(4-vinylphenol) PVPh revealed a large scatter of values ranging between 53 and 194 °C, which can only partially be attributed to molecular-mass effect. The reason could be seen in residual moisture and/or solvent in samples subjected to insufficient or even no drying. Based on selected two thirds of literature data, a regression equation is proposed for the dependence of Tg on 1/Mn. Two samples of commercial PVPh (Mn 11,500; Mw 22,100) and (Mn 19,700; Mw 40,900) were studied by DSC, ATR-FTIR, and SEC methods. A procedure of preparing well defined samples is proposed: PVPh vacuum-dried at 140 °C for 24 h is dissolved in tetrahydrofuran and precipitated in hexane. The precipitate is vacuum-dried at 40 °C for 24 h, weighed into a pierced DSC pan. After final vacuum drying at 140 °C for 24 h, the sample is analyzed. The PVPh samples treated in this way showed Tg of 175.0 °C and 179.6 °C, respectively.
Journal: European Polymer Journal - Volume 45, Issue 6, June 2009, Pages 1851–1856