Note on the glass transition temperature of Poly(vinylphenol)

Critical overview of literature data on the glass transition temperature T-g of poly(4-vinylphenol) PVPh revealed a large scatter of values ranging between 53 and 194 degrees 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 T-g on 1/M-n. Two samples of commercial PVPh (M-n 11,500; M-w 22,100) and (M-n 19,700: M-w 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 degrees C for 24 h is dissolved in tetrahydrofuran and precipitated in hexane. The precipitate is vacuum-dried at 40 degrees C for 24 h, weighed into a pierced DSC pan. After final vacuum drying at 140 degrees C for 24 h, the sample is analyzed. The PVPh samples treated in this way showed T-g of 175.0 degrees C and 179.6 degrees C, respectively. (C) 2009 Elsevier Ltd. All rights reserved.