Preparation And Evaluation Of The Molecularly Imprinted Polymers For Levofloxacin By Frontal Polymerization

Molecularly imprinted polymer(MIP)is the new technique for synthesizing the stationary phase with the ability of pre-selectivity.Molecularly imprinted polymer(MIP)is prepared by copolymerizing functional and cross-linking monomers in the presence of a template.After the removal of the template,the synthesized MIP possesses micro-cavities with a three-dimensional structure complementary in both shape and chemical functionality to that of the template,and is able to rebind the template.Frontal polymerization(FP)is a polymer synthesis technique that uses the exothermic reactions to form a self-sustaining wave.Because no additional heat is needed after the initial polymerization,the process has potential advantages over traditional polymerization methods:lower processing costs,less energy input and absence of solvent.These advantages make FP a potential viable option in polymer synthesis.Based on its unique pore characteristics and recognation properties,molecularly imprinted polymer has been strongly proposed for biomedical applications and widely used as protein separation media and immobilized catalytic materials.The preparation of porous molecularly imprinted polymer by frontal polymerization combined with foaming process was investigated in detail.The first synthesis of molecularly imprinted polymer by FP has been successfully carried out.The new technique was initially explored for the fabrication of other porous polymers.The main research work for the dissertation focused on five aspects.(1)The optimized S-OFX molecularly imprinted polymer was synthesized by frontal polymerization.The effects of the relative amounts of the reactants on the performances of the final products were investigated systematically.The highest absorbing ratio 213.99 ?mol/g were obtained.Compared with the product prepared by conventional batch polymerization route,the polymer produced by FP showed better pore structure and recognation capacity,3 times larger in pore volume and over 2 times high absorbing capacity of the conventional one.(2)We explored the effect of ratio between functional monomer and template on the recognition of the polymer.Take a fixed crosslinking agent,we changed the ratio of template and monomer,and respectively produced molecularly imprinted polymers on the template and functional monomer ratio 1:6,1:7,1:8,1:9,1:10.Results showed that the levofloxacin adsorption of polymer molecules reached to a stable point with the mother liquor concentration increases.In the the synthesis process,the varied proportion of templates and monomers influenced significantly differently in the adsorption process.Imprinted polymer's maximal adsorption reached the maximal point when the ratio of functional monomer and template is 1:7.(3)The polymerization of different co-monomers MAA and AAM via combining frontal polymerization and foaming process was presented,and the microstructures of final products were investigated.It was observed that the whole reaction can not go on without AAM.The polymer showed maximal absorbance when the ratio of co-monomer and functional monomer reached 1:1.5.The polymer consisted primarily of small particles with the diameter of ca.100 nm.These particles were cross-linked to form a rather continuous network.By close inspection,small holes were found in both upper crosslinked network and lower polymer.(4)The influences of foaming agent on recognation properties for the front characters and properties of porous polymers were studied.The recognation process was presented and the macrostructures of final products were investigated.The foaming agent concentration increased from 0.17g to 0.7g.The average cell diameter and the pore volume increased slightly.Absorbing experiment exhibited that the maximal absorbing volume rised to the summit when the foaming agent increased to 0.7g.(5)The effects of tube size on the front structures and characters of porous polymer were discussed.Five types of tubes with inner diameter from 15mm to 55mm were used to synthesize porous S-OFX molecularly imprinted polymer.Both front temperature and front velocity arose with the increasing tube diameter.Polymers with more connected porous structure and higher pore volume were obtained when the tube size was raised.SEM studies verified that the morphology of an monolith did not exhibit a visible radical gradient across the monolith surface.This implies that it is possible to prepare large size monoliths with uniform porous structures and excellent recognation properties by frontal polymerization.