Study On Preparation Of Monodisperse "Living" Polystyrene Microspheres

As a new functional material with excellent performance,monodisperse functional polymer microspheres have been widely used in fixed phase chromatography,solid phase extraction and molecular imprinting technology.As functional materials,monodisperse functional polymer microspheres are not only applied in every aspect of daily life,but also widely applied in the field of science and technology,such as medical and pharmaceutical fields,biochemistry fields,electronic information materials,etc.Because of its excellent performance,monodisperse crosslinked polystyrene microspheres have attracted more and more attention,and have been widely used in various fields,from the petrochemical industry at the beginning to the current medical field,electronic information field and more high-tech fields.Because of this,there are more and more researches on polystyrene microspheres in recent years,especially the preparation method of monodisperse cross-linked polystyrene microspheres,which has become a key research direction in this field.This topic through different ways of polymerization preparation of polystyrene microspheres,continuously improve the methods of preparation,the reversible addition-breaking chain transfer polymerization combined with a variety of free radical polymerization method,in order to get "living" monodisperse cross-linked polystyrene microspheres,and successfully obtained and single uniformly dispersed particle size,can be used for a variety of functional activity of polystyrene microspheres,and try to functionalization of shell.The research work of this paper mainly includes the following contents:(1)Monodisperse polystyrene microspheres were prepared by reversible addition-breaking chain transfer precipitation polymerization at different reaction temperatures with styrene as functional monomer,azodiisocyanidin as initiator,divinyl benzene as crosslinking agent and acetonitrile as reaction solvent.The results show that the preparation of monodisperse polystyrene microspheres by precipitation polymerization is difficult to master and requires a lot of experimental optimization.(2)using reversible addition-breaking emulsion polymerization of chain transfer mode synthesis of polystyrene microspheres,and by changing the emulsion polymerization reaction conditions(ionic strength,dosage of monomer,emulsifier,controllable reagent dosage),the preparation conditions were optimized,and good preparation for the spherical shape and narrow distribution,controllable particle size of polystyrene microspheres.The results showed that before demulsification,the microspheres prepared by emulsion polymerization had good morphology,narrow distribution and controllable particle size.After demulsification,the morphology of the microspheres was seriously damaged.Because emulsion polymerization involves demulsification steps,demulsification is time-consuming and laborious,and the environment is polluted,the method of preparing polystyrene microspheres by soap-free emulsion polymerization is explored.(3)The "living" cross-linked polystyrene microspheres were prepared by reversible addition-breaking chain transfer soaponeless emulsion polymerization,and the preparation conditions were optimized by changing the reaction conditions of soaponeless emulsion polymerization(KPS:BDC feed ratio,reaction time,reaction temperature,DVB concentration,DVB addition time).The experiment shows that the microspheres prepared when the amount of St is 3.23 ml,the amount of DVB is 2% of the total monomer volume,KPS:DBC is 1:4,the reaction temperature is 80?,DVB is added once,and the reaction time is 6h,the microspheres have good monodispersability and orderly morphology.(4)with chain transfer group polystyrene microspheres as the kernel of the carrier,through the surface of the RAFT polymerization,in the outer package is 4-vinyl-2,6-2,3,5 amino-1-triazine(VDAT)synthetic PS @ PVDAT,and through the measurement of particle surface Zeta potential laser granulometer,at the same time through the Fourier-its functional groups of infrared absorption spectra of functionalized modifications on "living" microspheres.