Preparation, characterization and application of chiral thermo-sensitive membrane for phenylalanine separation of the racemic mixture
writer：Xia Feng, Qiang Zhang, Xiaotong Liang, Jinling Li, Yiping Zhao*, Li Chen
keywords：chiral, thermo-sensitive, membrane
source：期刊
Issue time：2014年
PVDF-g-PNIPA, a thermo-sensitive polymers with poly(vinylidene ?uoride) (PVDF) backbones and poly(N-isopropylacrylamide) (PNIPA) side chains was synthesized via radical copolymerization. Chiral micro-gels was synthesized with N-isopropylacrylamide (NIPA) and chiral monomer which obtained by acrylation reaction with L-phenylalanine and acrylyl chloride. A novel chiral thermo-sensitive membrane for phenylalanine separation of the racemic mixture was prepared by phase inversion method with the blend of chiral micro-gels and PVDF-g-PNIPA. The chemical composition and morphology of the membrane were characterized by Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. The permeability, enantioselectivity, resolution mechanism and the effects of temperature, blending ratio and type of enantiomer molecules on the chiral recognition properties were studied. The results showed that the water flux of the membrane displayed temperature-sensitivity and the permeability of D-phenylalanine was better than that of L-phenylalanine. Comparing with chiral membrane at 40℃, the membrane at25℃obtained a larger number on percentage enantiomeric excess (e.e.%). The value of e.e.% and separation factor (α) at a temperature above the LCST was also much higher than that of membranes with no thermo-sensitivity at low temperature. The value of e.e.% and α increased with blending ratio increasing, when the blending ratio was 30 wt.% in chiral blended membrane, the value of e.e.% reached 10%. The model of the chiral membrane could be described as solution-diffusion model.