Synthesis Of Porous Resins With Epoxy Groups And Study On Its Application

Macroporous carriers with epoxy groups which had large surface area, big poreradius and easy reacting groups could immobilize the enzyme easily and keep most ofthe catalytic activity. So it attracted lots of interests in enzyme immobilizationmaterials. With sifting monomer containing epoxy group, crosslink agent and porogen,we could get excellent physical structure of the carriers and enzyme would beimmobilized well. However, there are little studies on the influence of different kindsof monomers with epoxy group and crosslink agents on epoxy group content, as wellas extent of reaction. In this text, we synthesized macroporous carriers with epoxygroups by kinds of epoxy monomers and crosslinking agents. Then we examined theirinfluence on Tg, swelling factor in water and epoxy group contents. We synthesizedmacroporous terpolymers with epoxy groups and studied the influence of chemicalcircumstances on lipase immobilization. The main work was:(1) Synthesis of macroporous resins with epoxy groupsA series of macroporous beaded copolymers were synthesized by suspensionpolymerization with glycidyl methacrylate (GMA), allyl glycidyl ether (AGE) asepoxy monomers and ethylene glycol dimethacrylate (EGDMA), tetraethyleneglycol dimethacrylate (TEGDMA) as crosslink agents, in which toluene andn-heptane were used as porogen. Then we examined their influence on particle sizedistribution, swelling factor in water, glass transition temperature and epoxy groupcontent. Carriers with AGE as epoxy monomers got higher glass transitiontemperature and epoxy group content compared with GMA carriers, but its sutiableparticle size distribution was not good. Carriers with TEGDMA as crosslink agenthad excellent extent of reaction, but their epoxy group content, glass transitiontemperature and swelling factor in water were low.(2) The influence of kinds and amount of third monomers on lipase immobilizationA series of macroporous beaded terpolymers with epoxy groups weresynthesized by suspension polymerization with GMA, EGDMA and the thirdmonomers including styrene (S), methyl methacrylate (MMA), n-butyl acrylate(BA), butyl methacrylate (BMA), and2-hydroxyethyl methacrylate (HEMA) forimmobilization of Candida lipolytica lipase. The effect of various thirdmonomers and its amount on loading and activity recovery of immobilized lipase were studied. The amount of lipase immobilized on poly(GMA-EGDMA-BA)carriers was about two times compared with other terpolymers and its activityrecovery reached79.0%. As the content of BA (%) increasing, the loading of lipaseenhanced, but the activity recovery reached88.5%for the initial stage anddecreased to46.9%at last. The poly(GMA-EGDMA-BA-10) showed an optimalresult in lipase immobilization. Lipase immobilized onpoly(GMA-EGDMA-BA-10) carriers had broader pH and higher temperaturestability.(3) The influence of kinds and amount of crosslinking agent on lipase immobilizationA series of macroporous beaded terpolymers with epoxy groups weresynthesized by suspension polymerization with GMA, EGDMA (TEGDMA) andBA for immobilization of Candida lipolytica lipase, in which amyl acetate andoctanol were used as porogen. We studied the influence of the kinds ofcrosslinking agengt and their amounts on loading ang activity recovery ofimmobilized lipase. Then we examined the optimal pH, temperature and thermalstability of the immobilized lipase under their optimal crosslinking densitycompared with free lipase. The amount of lipase immobilized onGMA-EGDMA-BA was4-5times of GMA-TEGDMA-BA, but the latter one hadhigher activity recovery. Both of the carriers got their best immobilized resultswhen the crosslinking density was60%. The optimal temperatures of lipaseimmobilized on GMA-TEGDMA-BA-60and GMA-EGDMA-BA-60were10℃and15℃higher than free lipase, respectively. Lipase immobilized onGMA-TEGDMA-BA-60and GMA-EGDMA-BA-60had broader pH and higherstability. Especially, after incubated at60℃for12omin, lipase immobilized onGMA-TEGDMA-BA-60carriers kept most of its activity.