Abstract: Henry's coefficient of volatiles in the polymer system is a crucial parameter reflecting the gas-liquid equilibrium, which is very important for the devolatilization process. In this research, POE-cyclohexane and PDMS-hexane systems were taken as examples, using the gas-liquid equilibrium method, Henry's coefficient was obtained by measuring the gas phase equilibrium partial pressure when polymer solution containing different mass fractions of volatiles reached a saturated state. The effects of temperature, kinds of volatiles and polymer viscosity on the gas phase equilibrium partial pressure and Henry's coefficient of volatiles were investigated. Experimental results indicate that, with the increase of temperature and polymer viscosity, the gas phase equilibrium partial pressure and Henry's coefficient of volatile cyclohexane increase. As temperature increases, the solubility of gas in liquid decreases. In POE-cyclohexane system, the relationship between Henry's coefficient of cyclohexane and temperature can be expressed by lnH=389.39-244402.54×(1/T)+3.86×10^7×(1/T)^(2 ). While in the PDMS-cyclohexane, it can be expressed by lnH=106.57-60139.08×(1/T)+8.69×10^6×(1/T)^2 . In PDMS-hexane system, the gas phase equilibrium partial pressure and Henry's coefficient of n-hexane with straight chain structure are higher than those of cyclohexane with cyclic structure. Henry's coefficient obtained in this study can provide a reference for perfecting the devolatilization process and improving the devolatilization effect.

Key words: Henry', s coefficient, gas-liquid equilibrium method, Hexane, polyolefin elastomer (POE), polydimethylsiloxane (PDMS)