Viscoelastic properties of solutions of polystyrene melts and carbon dioxide: Analysis of a transient shear rheology approach
Viscoelastic properties of solutions of polystyrene melts and carbon dioxide: Analysis of a transient shear rheology approach
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DOI：
10.1122/1.4708601
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发表时间：
2012-07-01
影响因子：
3.3
通讯作者：
Altstaedt, Volker
中科院分区：
文献类型：
--
作者：
Handge, Ulrich A.;Altstaedt, Volker
本文采用板板式流变仪对聚苯乙烯熔体和二氧化碳(CO2)溶液的粘弹、热和扩散特性进行了研究。本研究的目的是评估高粘度聚合物熔体的瞬时剪切流变学方法，验证聚苯乙烯/二氧化碳溶液的叠加原理，并测量玻璃化转变温度随压力和二氧化碳浓度的变化。采用二氧化碳饱和聚苯乙烯的两种不同方法，即在聚苯乙烯玻璃化转变温度以下负载发泡剂和在测量温度下负载发泡剂。为了测量聚苯乙烯/二氧化碳溶液在线性区域的瞬时粘度，进行了剪切应力增长实验。为了确定粘度的位移因子和平均松弛时间，将瞬时粘度数据平移到主曲线上。我们的数据表明，在实验散射范围内，稳态粘度和平均松弛时间与温度-压力-浓度移动因子a(T，p，c)成正比，因此，聚苯乙烯/CO2溶液符合时间-温度-压力-浓度叠加原理。聚苯乙烯的粘度强烈地依赖于施加的温度和压力，而弹性平衡柔量仅对温度和压力有微弱的依赖关系。(C)2012年香港流变学学会。[http://dx.doi.org/10.1122/1.4708601]
In this work, the viscoelastic, thermal, and diffusion properties of solutions of polystyrene melts and carbon dioxide (CO2) were analyzed using plate-plate rheometry in the transient mode. The objective of this study was to evaluate a transient shear rheology approach for high viscosity polymer melts, to verify superposition principles for polystyrene/CO2 solutions, and to measure the glass transition temperature as a function of pressure and CO2 concentration. Two different procedures of saturating polystyrene with carbon dioxide were applied, i.e., loading with the blowing agent below the glass transition temperature of polystyrene and at the measurement temperature. Stress-growth experiments in shear were performed in order to measure the transient viscosity of polystyrene/CO2 solutions in the linear regime. A shift of the transient viscosity data to a mastercurve was applied in order to determine the shift factor of the viscosity and the average relaxation time. Our data indicate that the steady-state viscosity and the average relaxation time are proportional to the temperature-pressure-concentration shift factor a(T,p,c) within experimental scatter, and consequently a time-temperature-pressure-concentration superposition principle holds for polystyrene/CO2 solutions. Whereas the viscosity of polystyrene strongly depends on the applied temperature and pressure, the elastic equilibrium compliance depicts only a weak dependence on temperature and pressure. (C) 2012 The Society of Rheology. [http://dx.doi.org/10.1122/1.4708601]