YAN Xiaowei, SHAN Yibin, WANG Jingdai, et al. Measurement of infinite dilution diffusion coefficients of small molecule solvents in nascent polyethylene particles by inverse gas chromatography[J]. CIESC Journal, 2007, (8): 1917-1925.
YAN Xiaowei, SHAN Yibin, WANG Jingdai, et al. Measurement of infinite dilution diffusion coefficients of small molecule solvents in nascent polyethylene particles by inverse gas chromatography[J]. CIESC Journal, 2007, (8): 1917-1925.DOI:
Based on the classical theory of linear and non-equilibrium chromatography process
the infinite dilution diffusion coefficients of dichloromethane
tri-chloromethane
tetra-chloromethane and n-hexane in nascent polyethylene particles were measured in the temperature range from 323.15 K to 358.15 K with inverse gas chromatography (IGC). Polyethylene particles
as obtained from the polymerization reactor
were directly used to prepare packed columns without any change of the polymer morphology. The effects of diffusion temperature
molecular weight of different solvents and polyethylene crystallinity on diffusivity were investigated. It was shown by the IGC results that the diffusion coefficients increased with rising temperature for a particular polymer/solvent system
while decreased with increasing molecular weight of diffusing solvent for homologue solvents
such as dichloromethane
tri-chloromethane and tetra-chloromethane. The crystallinity of semicrystalline polyethylene also affected the diffusion coefficients significantly in the way that higher crystallinity corresponded to lower diffusion coefficients for both dichloromethane and n-hexane. The measured diffusion coefficients were compared with model predicted values and good agreement was found
indicating the reported IGC method in this work had good reliability.