不同工艺条件下PS/ScCO2均相体流变特性研究

通过建立含有类似锥板流变仪结构的实验平台对不同的温度、压力、剪切速率以及CO2质量分数等工艺条件下聚苯乙烯(PS)/超临界CO2(ScCO2)均相体的流变性能展开研究。结果表明:压力的升高会增加均相体的黏度,压力由7.5 MPa升高到10.5 MPa时,CO2质量分数为0.5%的均相体黏度增加了140 Pa s,约为原来的4.6%;增加温度则会降低均相体黏度,而且随着温度的升高,黏度的下降趋势在逐渐减小,温度从443.15 K逐渐增加到473.15 K时,CO2质量分数为0.5%的均相体黏度的减少值分别为778,482,327 Pa s;当均相体中CO2质量分数逐渐增加时,其黏度变化呈线性下降,CO2质量分数每升高0.1%,均相体黏度下降约为52 Pa s;加大剪切速率可以大幅度降低均相体的黏度,当CO2质量分数为0.5%的均相体在剪切速率从(120/π)/s增加到(240/π)/s时其黏度下降趋势最大,值为40%。

Reserach on Rheological Properties of PS/ScCO2 Homogeneous Body Under Different Process Conditions

The rheological properties of polystyrene(PS)/supercritical CO2(ScCO2)homogeneous phase under different process conditions such as temperature,pressure,shear rate and CO2 mass fraction were studied by establishing an experimental platform with a similar cone-and-plate rheometer structure.The results show that the increase of pressure will increase the viscosity of the homogeneous body,when the pressure increases from 7.5 MPa to 10.5 MPa,the homogeneous body viscosity with 0.5%CO2 mass fraction increases by 140 Pa·s,which is about 4.6%of the original viscosity.The increase of temperature will decrease the viscosity of the homogeneous body,and with the increase of temperature,the decreasing trend of viscosity will gradually decrease,when the temperature increased gradually from 443.15 K to 473.15 K,the decrease values of homogeneous body viscosity with 0.5%CO2 mass fraction are 778,482,327 Pa·s,respectively.When the CO2 mass fraction in the homogeneous body increased gradually,the viscosity change decreases linearly,when the mass fraction of CO2 increases by 0.1%,the viscosity of the homogeneous body decreases about 52 Pa·s.Increasing the shear rate can greatly reduced the viscosity of the homogeneous body,when the shear rate increased from(120/π)/s to(240/π)/s,the downtrend of viscosity of the homogeneous body with a CO2 mass fraction of 0.5%is the largest,with a value of 40%.