Adsorption Membrane Based On Pillar[5]arene

Porous separation membranes are widely applied in the purification of chemicals and water,the research of advanced membranes are of great significance to sustainable development.To date,there are a great deal of functional porous materials such as zeolite,Metal-organic frameworks(MOFs),Covalent-organic frameworks(COFs),porous organic polymers(POPs)were utilized in the field of separation,but whose application were severely limited by the problems of hard to process and prepare into self-standing membrane.Pillararene,as a member of nonporous self-adaptive crystals,though it has aromatic macrocycle structure,abundant hostguest interaction and great potential in adsorption and separation,its application was constrained by the difficulty in membrane formation.To solve this problem,we prepared polypillararene containing block polymers based on pillar[5]arene,and their phase separation,membrane-forming,and application in separation were studied.The main content of the dissertation includes two parts as following:In the first part,an untraditional modification method was used to functionalize the side of pillar[5]arene with double bond,and further forming block polymers with several molecular weight by reacting alkyne-terminated polypillararene gained by controlled RAFT with azide capped polydimethylsiloxane(PDMS).The resulting polymers were characterized by Nuclear Magnetic Resonance(NMR),Gel Permeation Chromatography(GPC),Fourier Transform Infrared Spectrometer(FT-IR Spectrometer),Thermal gravimetric analysis(TGA),differential scanning calorimetry(DSC),small-angle X-ray scattering(SAXS),Transmission electron microscope(TEM)and BET adsorption isotherm.After thermal-anneal,part of them could form lamellar and hexagonal structures with orientation parallel or vertical to membrane respectively.In the second part,the phase-separable block polymers were processed into film by hotpress and sedimentation-thermal-anneal.The membranes,prepared by sedimentation-thermalanneal,were able to form a layer of polymer membrane like “reinforced concrete” with nylon fiber on the surface,which is capable to boost mechanic strength of membrane significantly.The thickness of these membranes are less than 2μm.Membranes prepared by this way owns uniform and fixed pore size,which could bond specifically with guest molecules,and this is the first example of non-blending porous separation membrane based on pillararene.The results show that the highest adsorption rate of these membranes to methylene blue aqueous is as high as 95.5%,and the membranes can be reused by washing the adsorbed methylene blue with methanol.After repeated for six times,the adsorption performance of the membrane remains the same.