Study On Preparation And Properties Of Rosin-based Chrysin Molecularly Imprinted Membranes

The separation and extraction of chrysin from active ingredients of natural products are of great significance,but the existing separation and extraction methods have certain drawbacks.In this dissertation,molecularly imprinted polymer(MIP),molecularly imprinted composite fiber membrane(MICM)and molecularly imprinted nanofiber membrane(MINM)with the ability to select and recognize chrysin were prepared by molecularly imprinted technology and electrospinning technology as well as the combination of the two technologies,and their adsorption properties of chrysin were further studied.The main contents are as follows:The molecularly imprinted polymer with high selectivity for chrysin was prepared by precipitation polymerization with chrysin as template molecule,methacrylic acid as functional monomer,ethylene glycol maleic rosinate acrylate(EGMRA)and Ethylene glycol dimethacrylate(EGDMA)as mixed crosslinking agent.The optimal synthesis conditions of the molecularly imprinted polymer were determined by single factor optimization experiments.The optimal synthesis condition is template molecule?functional monomer?crosslinking agent=1?8?32.The experiment shows that MIP with modified rosin crosslinking agent has good adsorption performance.The molecularly imprinted composite fiber membrane(MICM)were prepared by electrospinning,with polyvinyl alcohol(PVA)as the membrane substrate,adding the prepared molecularly imprinted polymer,the molecularly imprinted particles were successfully coated in nanofibers by electrostatic spinning.Then the spinning conditions were optimized by single factor experiment.According to the experiment,the optimal spinning conditions were as follows: the content of membrane material PVA in the solution was 8% and the content of MIP in the spinning solution was 0.2%.By FT-IR and scanning electron microscopy analysis,the MICM structure was compact and presented a three-dimensional network structure.Equilibrium adsorption experiments showed that the adsorption process of MICM was more consistent with Langmuir isothermal adsorption model,and the adsorption kinetics was more consistent with quasi-second-order kinetics model.The MICM had good selectivity and repeatability of chrysin.After repeated utilization for 5 times,the adsorption capacity only decreased by 7.74%.The MINM were prepared by electrospinning,with polyvinyl alcohol(PVA)and EGMRA as the membrane substrate.Then the spinning conditions were optimized by single factor experiment.According to the experiment,the optimal spinning conditions were as follows: the template molecule chrysin content was 0.25%,the rosin content was 10%,and the voltage applied during spinning was 20 k V.By FT-IR and scanning electron microscopy analysis,MINM had compact and uniform structure.Equilibrium adsorption experiments showed that the adsorption process of MINM was more consistent with Langmuir isothermal adsorption model,and the adsorption kinetics was more consistent with quasi-second-order kinetics model.The MINM had good selectivity and repeatability of chrysin.After repeated utilization for 6 times,the adsorption capacity only decreased by 12.08%.The Molecularly imprinted materials exhibited good selectivity and excellent reusability.Therefore,the chrysin molecularly imprinted materials proposed in this paper are promising materials for the adsorption and separation of chrysin.