Functionalization Of Monodisperse Polystyrene Microspheres

Polymer microspheres have been widely used in the fields of applied chemistry,medical treatment,electronics,and architecture because of their light weight,large specific surface area,and stable dispersion system.With the development of the times,it is necessary to functionalize polymer microspheres to meet the increasing demand in production and life.Monodispersed polystyrene microspheres have the characteristics of low price,high rigidity,and good monodispersity.Therefore,it is of great significance to use monodisperse polystyrene microspheres as the matrix for functional modification.In this paper,soap-free emulsion polymerization was used as the main research method to prepare polystyrene microspheres with good monodispersed,controllable particle size,and the surface was modified with a carboxyl group,sulfonic acid group,amino groups,and other groups.Carboxylic polystyrene microspheres were prepared by copolymerization of styrene(St)and carboxylic acid monomer with potassium persulfate(KPS)as initiator.The carboxylic acid monomer,electrolyte,p H value,solvent,and other variables of the polymerization system were adjusted,and their influence on the soap-free emulsion polymerization reaction system was systematically investigated.The results show that the obtained microspheres are highly monodisperse,with a particle size ranging from 200 to 1500 nm,and the surface carboxyl group content is 0.552 mmol/g.Based on the analysis of the changes of particle size and number in the reaction process,the mechanism of soap-free emulsion polymerization copolymer was explained.It was found that hydrophilic monomers help to promote particle nucleation,and the nucleated particles grow by the mechanism of monomer diffusion.The hydrophilicity of the carboxylic acid monomer decreases,the polymerization rate increases and the microsphere size decreases.Polystyrene functional microspheres modified by the surface sulfonic acid group were prepared by using sodium p-styrene sulfonate(Na SS)as anion copolymer.The P(St-coNa SS)microspheres were characterized by infrared analysis spectroscopy(FT-IR),transmission electron microscopy(TEM),dynamic light scattering technology(DLS),zeta potential measurements(ZP),and other means.It was studied that the Na SS has an excellent performance in stabilizing particles,increasing the polymerization reaction rate,and reducing the particle size;increasing the initiator concentration,the size of the microspheres increases;when the solid content of the system monomer is 25%,the emulsion can still remain stable.The crosslinking agent causes the particle size of the microspheres to decrease,and the chain transfer agent causes the particle size to increase.The P(St-co-Na SS)microspheres are mass-scaled and produced,the preparation process is simple,the difference between the batches of the obtained products is small,and the particle size can be continuously controlled.Amino polystyrene microspheres were prepared by one-step polymerization reaction and surface chemical modification.In the copolymerization of styrene and cationic monomer Methacrylatoethyl trimethyl ammonium chloride(DMC),the initiator 2,2'-Azobis(2-methylpropionamidine)dihydrochloride(AIBA)is used to copolymerize amino groups on the surface of the microspheres.The effects of initiator type,content,and DMC content on the polymerization kinetics,size,and morphology of microspheres were investigated.In the chemical modification method,a nitrification reduction process was used to successfully prepare aminated polystyrene microspheres.