The Preparation Of Phase Transfer Catalyzed Polypyrrole Microcapsules And Its Sustained Release Properties Can Be Controlled

At present,microencapsulation technology has been widely used in phase change materials,phase transfer catalyst,food additives,beverage industry,dairy products,candy,gel breaker,biopharmaceutical and many other fields which have important theoretical research value and great practical application value.The preparation methods of microcapsules are very mature.It mainly contains physical method,chemical method and physical-chemical method,among those the most widely used method is chemical method.but in chemical method,the application and the usage frequency of in situ polymerization and interfacial polymerization are at most and tallest.The microcapsules with controlled slow release properties in the article selected water-soluble initiator(KPS)? oil-soluble initiator(BPO)and azo-initiator(AIBN)as the core materials,polypyrrole(Ppy)as the shell materials which were prepared successfully by in situ-interfacial copolymerization and suspension-dispersion-polymerization(It could be used in the area of phase transfer catalyst).The preparation,study on the mechanism of slow release and constructing kinetics model of microcapsules were all studied.Therefore,the research content of this paper is mainly from the following three parts:1.Preparation and characterization of KPS @ Ppy core-shell microcapsules with controlled slow release propertiesThe microcapsules containing KPS as the core materials,polypyrrole as the shell materials were prepared by in-situ interfacial copolymerization in the mixed solvent of isopropanol?n-butyl alcohol and water.The encapsulation efficiency of KPS reached peak at 95%in the microcapsules.The controlled slow release time of KPS could be at 3-14h from the microcapsules.The microcapsules prepared were characterized by TEM?SEM?XRD?FTIR?TGA?DLS and the other methods,the structure?morphology?particle size and thermal stability of microcapsules could be measured by means of the above characterization.Based on the construction of the kinetic model of the release process of microcapsules,the kinetic model of the controlled release at 40? was close to zero-order kinetic mode while the kinetic model of the controlled release was close to the first-order kinetic model at 80?.2.Preparation and characterization of BPO @ Ppy core-shell microcapsules with controlled slow release propertiesThe microcapsules containing BPO as the core materials,polypyrrole as the shell materials were prepared by suspension-dispersion-polymerization in the water.The encapsulation efficiency of BPO reached peak at 83%in the microcapsules.The controlled slow release time of BPO could be at 5-17h from the microcapsules.The particle size of samples were 600-800nm.By adding different emulsifier components of SDS?SDS/PEG 600 and SDS/PEG 2000,the stability and dispersion properties of microcapsules were studied.Intensities of the characteristic peaks of UV-absorption spectrum increased with the increase of encapsulation efficiency of BPO and so on.The microcapsules prepared also had good storage stability.Based on the construction of the kinetic model of the release process of microcapsules,the kinetic model of the controlled release combined first-order kinetic equation and Higuchi kinetic equation at 40? while the kinetic model of the controlled release was close to the Higuchi kinetic model at 60?.3.The practical application of release of Ppy microcapsules in phase transfer catalysisThe preparation process of KPS @ Ppy core-shell microcapsules was in the oil solvent while the slow release process of microcapsules completed in the water.Adding AIBN?pyrrole monomer and emulsifiers,etc in the above aqueous solution without shell materials of Ppy,the core materials of KPS released in the water also led to the preparation of AIBN @ Ppy core-shell microcapsules.The preparation process of BPO @ Ppy core-shell microcapsules was in the water while the slow release process of microcapsules completed in the oil solvent.Adding styrene monomer mixed with butyl acrylate monomer and emulsifiers,etc in the above water solution without shell materials of Ppy.Heating to 70? and agitating for about 6h at this temperature,the core materials of BPO released in the oil solvent could contributed to polymerization with styrene and butyl acrylate.The samples were characterized by a series of simple characterization methods,such as TEM?FTIR and so on.