Separation Properties Of Membranes Of Polyacetylene Derivatives And Their Hybrid Nano Composite

Substituted polyacetylenes not only possess the characteristics of amorphous structure of ordinary glassy polymer, what’s more, with high rigidity, outstanding gas permeation property, they can be used as potential material of membrane separation. As one kind of membrane material with potentially high performance, CNTs/polymer hybrid membrane can improve selectively separation performance of substituted polyacetylenes. In this paper, several kinds of substituted polyacetylenes and their CNTs hybid composite membranes are made and their gas permeation and butanol/water pervaporation properties are studied. The results are as follows:(1) Effect of aging on the gas permeation properties of poly(1-trimethylsilyl-l-propyne)(PTMSP). Membrane of PTMSP was prepared through solution casting and membrane thickness was50-202μ,m. The effect of membrane thickness, storing temperature and storing atmosphere on membrane gas permeability was examined. The results showed that the gas permeation coefficient of PTMSP membrane reduced rapidly with membrane thickness decreased. High temperature could induce chemical aging, which resulting microstructure of PTMSP changed, forming polar groups such as C=O in the polymer, and then increasing packing density of polymer chains, reducing internal free volume ratio, causing gas permeation coefficient decreased rapidly. The gas solution coefficient of PTMSP did not change with stocking time and the main reason of decreased gas permeation coefficient was caused by the decreased gas diffusion coefficient.(2) Butanol/water pervaporation property of [1-(4-(trimethylsilyl))phenyl-2-p-phenylacetylene](PTMSDPA). Homogeneous membrane of PTMSDPA was prepared through solution casting and effect of feed concentration and feed temperature on the pervaporation performance was investigated. As feed concentration increased, the total permeation flux and butanol flux increased significantly while the permeation of water changed little. The separation factor of butanol/water on pervaporation and adsorption performance all first increased and then decreased as feed concentration increased, and got the maximum value at the concentration of1.5wt%. As feed temperature increased, the permeation flux of total and partial component all increased significantly while the separation factor of butanol/water mixed system decreased rapidly. (3) Pervaporation and gas separation performance of PTMSDPA/Carbon nanotubes (CNTs) hybrid composite membrane. Several PTMSDPA/CNTs hybrid composite membranes with different content of CNTs were made and the effect of structure and content of CNTs on gas separation and pervaporation performance of PTMSDPA/CNTs hybrid membrane were investigated. As the content of CNTs increased, the gas permeation coefficient of PTMSDPA/CNTs composite membranes increased, and got the maximum value at the content of10wt%. The effect of inner diameter and length of CNT on gas permeation performance of PTMSDPA/CNTs membrane was deeper. When the content of CNTs reached15wt%, the permeation flux of butanol/water mix and separation factor all got to the maximum value.