Visualization for measuring the PVT property of viscoelastic polystyrene/CO₂ mixtures at elevated temperatures and pressures

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• 作者：Y.G. Li ; S.H. Mahmood ; C.B. Park ; ^{park@mie.utoronto.ca" class="auth_mail" title="E-mail the corresponding author}
• 关键词：PVT ; Volume swelling ; Degree of asymmetry ; Polystyrene ; Carbon dioxide
• 刊名：Polymer Testing
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：55
• 期：Complete
• 页码：88-96
• 全文大小：1551 K

文摘

Pressure-volume–temperature (PVT) data for polymer/gas solutions are fundamental to the design and control of such polymer processes as injection molding, foaming, blending and extraction reaction. Previous studies have offered methodologies based on the observation of an axisymmetric polymer pendent/sessile drop, which is used to measure the polymer's PVT behavior at elevated temperatures and pressures. Because polymer generally has high viscosity and elasticity, it is not easy to form an axisymmetric shape out of some types of polymer drops. Our study uses a novel rotational device in a high-pressure and high-temperature cell with a visualization window. This makes it possible to measure the PVT behavior of polymer/gas solutions in those cases where it is not easy to obtain an axisymmetrically-shaped polymer drop. The degree of asymmetry is mathematically defined, and an algorithm is developed to integrate the asymmetric profile for determining the PVT (that is, the volume swelling) of the polymer/gas solution. We have presented a case study on the pressure-volume-temperature (PVT) property of a polystyrene (PS)/CO₂ solution at temperatures elevated in the range of 423 K–523 K and at pressures from 6.895 MPa to 27.579 MPa. We found that the volume of the asymmetric sessile drops of PS/CO₂ in the PS melt determined the extent of the melt's swelling with the dissolved CO₂.