Preparation, Properties And Application Of PH-and Thermo-Responsive Polymer Membrane

Environmental responsive intelligent polymer membrane has broad prospects in material separation, control and release. At present, the research focuses on the intelligent polar membrane and intelligent processing on surface of the membrane materials that already existed. Therefore, a deep research on the preparation method and response mechanism of non-polar intelligent membrane and self-supporting intelligent membrane and building polymer smart film concept in microcapsule had great magnificence in creating intelligent polymer film with good performance.The main work and innovation of the thesis were listed as following:(1) Amphiphilic block copolymers PnBA-b-PDEAEMA with a narrow PDI and controllable structure were prepared by Atom Transfer Radical Polymerization (ATRP) using ethyl acetate as solvent. Polypropylene (PP) microfiltration (MF) membrane was functionalized by surface entrapment process with PnBA-b-PDEAEMA as the surface modification agent. The effects of modifiers, solvent and processing temperature on hydrophilia and surface morphology of the PP MF were inversigated. The optimal condition was that taking20g/L PnBA49-b-PDEAEMA106THF solution as modifier at40℃. Contact angle of the microfiltration membrane was26℃under the optimal conditions.(2) Amphiphilic block copolymers PS-b-PDEAEMA with a narrow PDI and controllable structure were prepared by ATRP. The novel pH-responsive P(St)71-b-PDEAEMA31and P(St)71-b-PDEAEMA82micro-porous membranes were prepared via the non-solvent-induced phase separation (NIPS) process. The influence of pH value in the coagulation bath, the solvent, the "open-time" and the polymer composition onto the membrane morphology were investigated. The most optimal preparation condition of the membrane was a mixture solvent of25%THF/75%DMF, with mold liquid concentration at5wt%, volatilization time at20s, and the pH value of coagulating bath at2. (3) The pH-and/or thermo-responsive ethyl cellulose graft copolymers EC-g-PDEAEMA, EC-g-PNIPPAm and EC-g-PDMAEMA were synthesized via ATRP. Micro porous membranes of EC-g-PDEAEMA, EC-g-PDMAEMA and EC-g-PNIPPAm were prepared by NIPS. The effects of solvent, volatilization time and the polymer composition on the molding and structure of the membrane were examined. The mechanism on the formation of pores for EC based graft copolymer during the NIPS process was proposed. The most optimal condition for preparing pH-responsive EC-g-PDEAEMA microporous membrane was using EC0.2-g-PDEAEMA32as the film-forming material,75%THF/25%DMF as solvent, with mold liquid concentration at15wt%and volatilization time at1min. The most optimal condition for preparing temperature-responsive EC-g-PNIPPAm microporous membrane was using EC0.2-g-PNIPPAm34as the film-forming material,75%THF/25%DMF as solvent, with mold liquid concentration at15wt%and volatilization time at1min. The critical temperature was approximately35℃. The most optimal condition for preparing pH and temperature responsive EC-g-PDMAEMA microporous membrane was using EC0.1-g-PDMAEMA32as the film-forming material,75%THF/25%DMF as solvent, with mold liquid concentration at15wt%and volatilization time at30s.(4) Intelligent polymer film concept was applied to build mugwort microcapsules. pH or/and temperature responsive microcapsules were prepared taking mugwort extract as core materials, taking EC-g--PDEAEMA, EC-g-PNIPPAm, and EC-g-PDMAEMA as wall materials respectively by emulsion solvent evaporation method. The most optimal preparation condition of the microcapsule was that the emulsifier was PVA, wall material concentration was2.5wt%, concentration of mugwort extract was2wt%, and core-shell ratio was50:50. The anti-bacterial rate of the EC0.1-g-PNIPPAm2o-mugwort extract micro capsule to Escherichia Coli was92%at20d which reflected the prominent antibacterial effect of holding. Temperature-sensitive microcapsule had a better antibacterial effect at37℃. (5) Thermo-responsive chitosan graft copolymer CS0.1-g-PNIPPAm22was prepared by ATRP, and temperature-responsive microporous membranes were prepared taking SiO2as pore-forming agent. Thermo-responsive microcapsules were prepared taking Artemisia Argyi Oil as core materials, CS0.1-g-PNIPPAm22as wall materials by the way of single coacervation. The antibacterial rate of the EC0.1-g-PNIPPAm2o-Artemisia Argyi Oil microcapsule to Escherichia Coli was94%at20d which reflected the prominent antibacterial effect of holding. Temperature-sensitive microcapsule had a better antibacterial effect at37℃.