PREPARATION OF SULPHONATE-CONTAINING POLYMER PARTICLES VIA SEMI-CONTINUOUS EMULSION COPOLYMERIZAION OF STYRENE AND SODIUM STYRENE SULPHONATE

Submicron-sized P（St-NaSS） latexes were prepared via a semi-continuous emulsion copolymerization of styrene （St） and sodium styrene sulphonate （NaSS） in the presence of anionic surfactant, in which NaSS aqueous solution and St were separately dropwise charged into the polymerization system at the same time. The hydrodynamic diameter of the latex particles was measured by dynamic light scattering （DSL） method, and the NaSS unit content of the purified copolymer by water extraction was calculated based on the elementary analysis. Results showed that the copolymerization could be performed smoothly with the monomer conversion more than 96% in the absence of crosslinker, and PNaSS homopolymer could be removed from the latex product by water extraction for 28 h. The weight loss in the water extraction tended to decrease and the NaSS unit content of the purified copolymer tended to increase with the increase of monomer feeding time, and both of them increased with the increase of NaSS/St mole ratio in the charge. The introduction of divinyl benzene （DVB） could decrease the weight loss in the water extraction and increase the NaSS unit content of the purified copolymer. When 25/75 mole ratio of NaSS/St and 11 mol% DVB of total NaSS and St were used in the recipe, and the monomer feeding time was 3 h in copolymerization, the NaSS unit content of the purified copolymer reached 7.31 mol%.

新型共聚物催化剂在醋酸异丙酯合成中的应用

采用新型磺化聚苯乙烯-co-甲基丙烯酸丁酯P(St-co-BMA)代替传统的浓硫酸催化异丙醇与冰乙酸的酯化反应。实验结果表明,P(St-co-BMA)对醋酸异丙酯的合成反应具有较好的催化活性。醋酸异丙酯的产率与新型催化剂的用量有关,当m(催化剂)∶m(异丙醇)=0.2∶1.0、酯化反应时间5 h时,醋酸异丙酯产率可达到74%以上。合成的共聚物催化剂经5次使用后,使醋酸异丙酯产率仍可达68%。该催化剂可用稀硫酸再生,多次使用过的催化剂经再生后的催化活性与新制备的共聚物催化剂的催化活性相比几乎没有差别。