Preparation And Application Research On Coupling Protein Of Surface Carboxyl Polymer Microspheres

Surface carboxyl polymer microspheres refer to the surface of the microspheres containing functional groups of carboxyl(-COOH). These microspheres with carboxyl groups can be carried out a series of reaction applying to modification, super hydrophilic coating material, improving the colloidal stability, coupling protein, etc.In this paper, firstly, the smooth micro spheres (less than 100nm) were studied by soap-free emulsion polymerization:the amount of 2,2'-azobisisobutyronitrile(AIBN) as initiator determined particle size and the amount of ionic copolymerization monomer sodium styrene sulfonate(NaSS) impacted stability of the system though Zeta potential. The amount of functional monomers acrylate(AA) affected the surface carboxyl relative content so as to influence coupling protein. The best system of coupling protein was that the amount of NaSS and AIBN was both 2% and AA was 0.25 mL after 6 hours's reaction. Reactivity of coupling protein was as large as 268%, coupling effect was good.Secondly, adding a certain proportion of crosslinking agent divinyl benzene(DVB), hydrophilic monomer methacrylic acid(MAA), water-soluble initiator ammonium persulfate(APS) to obtain rough surface microspheres(500-700nm) after 50min's reaction in methanol/water(6/4) system by two step dispersion polymerization. The amount of crosslinking agent influenced the crosslinking density of microspheres and phase separation. The amount of hydrophilic carboxylic monomer could promote the phase separation and increase the amount of carboxyl in the microspheres. Water-soluble initiator was able to enhance the interfacial polymerization reaction, refeeding functional monomer AA after 5h's reaction to obtain the big particle size of surface rough carboxyl microspheres, the effect of coupling protein is better than smooth microspheres with the same size, but inferior to the small particle size microspheres.Similarly, feed a certain amount of DVB, MAA, APS after 3.5 hours to prepare polymer microspheres(500-700nm) with inner hole inside by two step dispersion polymerization, refeeding AA after 2.5 h's reaction to bring carboxyl to surface of microspheres. In comparing experiments, two series of microspheres placed after a period of time, the microspheres with inner-pore did not appear statified phenomenon and stability was better than solid ones.