无皂乳液聚合法制备P(St-MMA-SPMAP)单分散乳胶颗粒

利用无皂乳液聚合 ,分别用一步法和两步法合成了单分散的聚 (苯乙烯 甲基丙烯酸甲酯 甲基丙烯酸丙基磺酸钾 ) (P(St MMA SPMAP) )乳胶颗粒 .在该聚合体系中 ,当水溶性磺酸基单体SPMAP的浓度小于 17mmol L时 ,为均相成核过程 ,能制备单分散的乳胶颗粒 .其中 ,用两步法制备的乳胶颗粒相互之间无粘连 .此外 ,还对一步法合成苯乙烯 甲基丙烯酸甲酯 甲基丙烯酸辛基磺酸钠 (P(St MMA SOMAS) )乳胶颗粒进行了初步研究 .

PREPARATION OF MONO-DISPERSED COLLOIDS OF P(ST-MMA-SPMAP) BY SOAP-FREE EMULSION COPOLYMERIZATION

The mono dispersed colloids of poly(styrene methyl methacrylate 3 sulfopropyl methacrylate,potassium salt) P(St MMA SPMAP) were prepared with soap free emulsion copolymerization usinge a one step or two step method.The particle size decreases with increasing the SPMAP amount mainly due to the formation of more nucleus at higher concentration of SPMAP.Although homogeneous latex with narrow particle size dispersion can be obtained with the one step method,the colloids prepared with this method are difficult to use in preparation of colloidal crystals because of heavy aggregation of the colloids.The two step method can resolve this problem,the colloids prepared do not show any aggregation and are suitable to the preparation of colloidal crystals.A homogeneous nucleation is realized when the concentration of water soluble monomer,SPMAP,is less than 17mmol·dm -1 .If 3 sulfooctyl methacrylate,sodium salt (SOMAS) is used instead of SPMAP the mechanism of the emulsion polymerization becomes rather complex,because the SOMAS will play a role of emulsion agent and in this case the mono dispersed colloids are difficult to be prepared.In this article the preparation of poly(styrene methyl methacrylate 3 sulfooctyl methacrylate,sodium salt) P(St MMA SOMAS) colloids using a one step method is also reported preliminary.