药用聚丙烯酸酯乳液的合成与表征

Synthesis and Characterization of a Pharmaceutical Polyacrylate Emulsion

利用衣康酸二正丁酯（DBI）与丙烯酸乙酯（EA）、甲基丙烯酸甲酯（MMA）以及丙烯酸（AA）为单体,选择十二烷基硫酸钠（SDS）和聚乙二醇辛基苯基醚（OP-10）为复合乳化体系,过硫酸钾（KPS）为引发剂,通过种子乳液聚合方法制备了固含量约为31.48%的EA/MMA/AA/DBI四元共聚物乳液。系统考察了反应条件对单体转化率和平均粒径的影响,借助于粒度分布仪、差示扫描热分析仪（DSC）、凝胶色谱（GPC）、透射电镜（TEM）和红外光谱仪（IR）表征了EA/MMA/AA/DBI共聚物乳液的特性：玻璃化转变温度Tg为6.27℃,共聚物的相对分子质量Mn^-=7.8428×10^5,Mn^-=3.3373×105,分散性Vp=Mn^-/Mn^-=2.35,乳胶粒呈球形,平均粒径为100nm。确定了较佳的反应条件为：乳化剂用量为4.5%-5.5%,引发剂用量为0.45%-0.55%,AA用量为1.0%,DBI用量为0.5%。此时,粒径分布较窄,乳液性能优良。实验结果表明,加入极少量的衣康酸二正丁酯可使共聚物膜的吸水率明显降低。

Using dibutyl itaconate （DBI）, ethyl acrylate （EA）, methacrylate （MMA） and acrylic acid （AA） as raw monomer materials, sodium iauryl alkyl sulfate （SDS） and OP-10 as complex emulsifier system and potassium peroxy-sulfate （KPS） as initiator, the EA/MMA/AA/DBI copolymer emulsion with solid content of 31.48% was prepared by seed emulsion polymerization. Effects of reaction factors on monomer conversion and mean diameter of the emulsion were studied, and the prepared copolymer was tested and characterized by Infra-red spectrum （IR）, Differential Scanning Calorimetry （DSC）, Gel Permeation Chromatography （GPC）, Transmission Electron Microscope （TEM）, and ZataSizer for particle size distribution. The DSC pattern of the prepared copolymer emulsion shows that its vitrification temperature （Tg） is 6.27℃. The GPC chromatogram of the copolymer shows that its weight-average molecular weight is equal to 7.8428×10^5, number-average molecular weight is 3.3373 × 10^5, and poly dispersion is 2.35. Particle morphology of the prepared copolymer emulsion was examined by TEM, and spherical emulsion particles with mean diameter of about 100 nm were observed. The most optimum reaction conditions of EA/MMA/AA/DBI copolymer emulsion preparation were found as follows： emulsifier dosage is 4.5%-5.5%, initiator dosage is 0.45%-0.55%, AA content is 1.0% and DBI content is 0.5%. Using above reaction conditions, the synthetic latex prepared has narrow particle size distribution and excellent properties. Experimental results also show that the water absorption of the copolymer membrane formed by the emulsion prepared can be evidently reduced by adding very little amount of DBI.