Expanded polystyrene (ePS) plays an important role in the food packaging industry. However, the foaming process is environmentally unfriendly. A sustainable alternative is dissolving supercritical CO (scCO) in the polystyrene (PS) matrix. Most studies so far were performed at temperatures above the PS glass transition temperature; however, a more general temperature window is desirable. In this work, the solubility of scCO in polystyrene was measured at 323 K, 343 K, 363 K and 383 K and pressure up to 130 bar using a magnetic suspension balance (MSB). It was concluded that the solubility of CO in PS decreases with temperature and increases with pressure. The Sanchez-Lacombe Equation of State was utilized to estimate the degree of swelling. The model developed was able to derive the experimentally determined solubilities after correction for the swelling. The interaction parameter, k, turned out to be only a function of temperature. With these results the solubility and swelling of PS in scCO can be more accurately assessed for different temperatures and pressures.

中文翻译：

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超临界CO2在聚苯乙烯中的溶解度


发泡聚苯乙烯（ePS）在食品包装行业中发挥着重要作用。然而，发泡过程对环境不利。一种可持续的替代方案是将超临界二氧化碳 (scCO) 溶解在聚苯乙烯 (PS) 基质中。迄今为止，大多数研究都是在高于 PS 玻璃化转变温度的温度下进行的；然而，更一般的温度窗口是可取的。在这项工作中，使用磁悬浮天平 (MSB) 在 323 K、343 K、363 K 和 383 K 以及高达 130 bar 的压力下测量了 scCO 在聚苯乙烯中的溶解度。结论是CO在PS中的溶解度随着温度的升高而降低，随着压力的升高而升高。利用桑切斯-拉科姆状态方程来估计肿胀程度。所开发的模型能够在校正膨胀后得出实验确定的溶解度。结果表明，相互作用参数 k 只是温度的函数。通过这些结果，可以在不同温度和压力下更准确地评估 PS 在 scCO 中的溶解度和膨胀。