Preparation Of Polysufide Click Functional Microspheres With Antibacterial/Antioxidant Properties

Polymer microspheres can be functionalized by encapsulating small molecules with special functions or by loading functional groups on the surface of microspheres because of their large specific surface area,simple size regulation,high loading capacity and easy surface modification.The polymer microspheres can be prepared by free radical polymerization or stepwise polymerization.Compared with the free radical polymerization initiated by high temperature heat,the reaction conditions of the thiol-ene click polymerization of the stepwise polymerization reaction are mild,and they can realize quantitative conversion,high yield,and no side effects,which attracts attention in the preparation of functional microspheres.At present,there have been studies on the preparation of polysulfide microspheres encapsulating essential oils(EO)by photocatalytic or thermally initiated thiol-ene click polymerization,but there has not been encapsulate EO through one step alkali-catalyzed thiol-ene click polymerization and realize complete release of EO in EO-polysulfide microspheres.At the same time,we evaluate the antibacterial/antioxidant ability of EO-polysulfide microspheres.Antibacterial microspheres can also be prepared by free radical polymerization from monomers containing quaternary ammonium salts.There is no research on polysulfide functional microspheres that involves grafting quaternary ammonium salts on the surface of polysulfide microspheres to obtain antibacterial functional microspheresHerein,we put forward the topic:1)Using miniemulsion polymerization to prepare the poly sulfide microspheres loaded with essential oils(EOpolysulfide microspheres),and explore the effect of EO addition on the microspheres,the loading and release capabilities of EO-polysulfide microspheres,and explore the capacity of antibacterial or antioxidant of the microspheres.2)Preparing thiol-polysulfide click microspheres with uniform particle size through TEA-catalyzed thiol-ene click reaction,and then use more basic DBU-catalyzed thiol-ene click particles on the surface of the microspheres graft on quaternary ammonium salt functional groups,finally,explored the amount of the quaternary ammonium salt functional groups on the surface of the particles and antibacterial ability of the microspheres.The main work contents are as follows:1.Preparation of EO-polysulfide microspheres by miniemulsion polymerization.1)Using ethyl acetate as a diluent to change the viscosity of the monomer,explore the method of preparing stable and uniform polysulfide click particles through a homogenizer and ultrasonic processor;2)Using essential oils(EO)(eugenol(EG)/methyl eugenol(MEG))instead of ethyl acetate as the diluent of the reactive monomer to prepare polysulfide click particles and realize the loading of EO;The morphology of the microspheres was characterized by SEM,the components of the microspheres were analyzed by infrared absorption spectroscopy,the absorbance of the supernatant was analyzed by a UV spectrometer and the TGA curve of the product was analyzed to determine the loading efficiency of EG/MEG.The difference of loading efficiency of microspheres on EG and MEG was studied.Finally,the antibacterial/antioxidant ability of EO-polysulfide click microspheres was evaluated by flat coating method and DPPH free radical scavenging method.2.Preparation of QAC-polysulfide microspheres by disperse polymerization.1)Preparation of polysulfide click particles with different cross-linking degrees by triethylamine(TEA)catalysis.The effect of cross-linking degree on particle size is discussed,and pentaerythritol tetrakis(3-mercaptopropionate)(PETMP)and di(trimethylolpropane)tetraacrylate(DTPTA)are used as the reaction model to explore the influence of monomer concentration,stabilizer amount and catalyst amount on the microspheres;2)Triethylamine(TEA)catalytic functional groups are fed in non-equal molar ratio to obtain thiol-functionalized poly sulfide click particles.The effect of non-equal molar ratio feed on particle morphology and dispersibility is explored,and the content of residual sulfhydryl groups on the microspheres surface is determined by the Ellman method;3)Exploring the preparation method of quaternary ammonium saltpolysulfide click microspheres,quaternary ammonium salt-polysulfide click particles were prepared by 1,8-diazabicyclic undecyl-7-ene(DBU)catalyzed-C=C-on APTAC react with the remaining sulfhydryl groups on the surface of the microspheres.The comparison of the remaining sulfhydryl content on the surface of the particles before and after grafting,FTIR analysis and TGA test were used to analyze the difference of the thermal weight loss curve before and after grafting to confirm the successful grafting of APTAC and the analysis of the grafting amount.Finally,the antibacterial activity of QAC-polyether click microspheres was evaluated.