Hydrophilization Of Polypropylene Membranes

Hydrophilization is one of the most important methods to improve the performance of polymeric membranes. Understanding the microscopic interaction between the membranes and the feed system is rather important for the selection of hydrophilization strategies. However, this is difficult because of the lack of suitable characterization tools. Molecular simulation is a good choice to investigate the microscopic world. The capacity of dealing with the time evolution of large systems makes the molecular dynamics (MD) method especially suitable for the research on the interaction between polymeric membranes and the feed system. The work in this essay focuses on the hydrophilization of polypropylene membrane, which can be divided into two parts:the surface-based hydrophilization and the bulk-based hydrophilization.In the first part, molecular models of hydrophilized microporous polypropylene membrane surface were built and the interaction between these surface models and water/isopropanol molecules was discussed. Investigation on the interaction between these surface models and protein sub domain was also carried out. The results reveal that the adsorption of protein on hydrophilized surface is energetically suppressed, and the suppression comes from the increase of membrane/water interaction by hydrophilization, rather than the decrease of the membrane/protein interaction. The above simulation conclusions was proved useful in explaining the previous works of our group on the surface hydrophilization of MPPM.In the second part, the molecular model of poly(GAMA) membrane was built and the diffusion of water/isopropanol molecules in the membrane was investigated. The results prove the hydration of GAMA units and show the diffusion selectivity on water. From these simulation results, a MPPM-based glycopolymer pore-filled membrane was fabricated and applied to the pervaporation dehydration of isopropanol. The pore-filled membranes show permeation selectivity on water and the separation factor is 105.9 at best, with high normalized flux. The results prove the feasibility of applying glycopolymer into the fabrication of pervaporation dehydration membranes.