含三苯基乙基苯氧基聚氧乙烯醚甲基丙烯酸酯功能单体的缔合型乳液增稠剂的制备及增稠机理  

Preparation and Thickening Mechanisms of Associative Latex Thickeners Using Triphenylethyl Phenoxy Polyoxyethylene Ether Methacrylate as Functional Monomer

作　　者：朱晓丽[1] 孔祥正[1] 刘永祥[1] 刘冉[1] 张志国[1] 

机构地区：[1]济南大学化学化工学院,济南250022

出　　处：《化学学报》2008年第22期2525-2532,共8页Acta Chimica Sinica

基　　金：山东省博士基金(No.2006BS04032)资助项目.

摘　　要：采用半连续法乳液聚合以甲基丙烯酸、丙烯酸乙酯、邻苯二甲酸二烯丙酯和不同量的功能单体三苯基乙基苯氧基聚氧乙烯醚甲基丙烯酸酯(SEM-25)为原料合成了疏水改性碱溶性增稠剂乳液.测定了增稠剂乳液的粘度、透光率、pH、粒径及其分布,结果表明随着pH值的增加,乳液的粘度和透光率首先迅速升高,然后缓慢下降.随着SEM-25用量的增加,乳胶粒的粒径先增大后减小.与不含SEM-25的乳液增稠剂相比较,SEM-25低含量增稠剂的增稠效果和抗剪切性没有提高,只有当SEM-25用量提高至单体质量的12%,且乳液固含量大于0.65%时,所制备缔合型增稠剂乳液的粘度和流变性比不含SEM-25的增稠剂才有明显提高.在此基础上研究了增稠剂对苯丙乳液的增稠性.含有增稠剂的苯丙乳液的粘度和透光率随pH值的变化与纯增稠剂乳液的变化类似.只有当加入0.34wt%苯丙乳液固体质量的增稠剂,并且增稠剂中SEM-25含量达到5wt%时苯丙乳液的粘度与使用不含SEM-25的增稠剂增稠的粘度相比才有明显增高.在此基础上对增稠剂的增稠机理进行了探讨.Alkali soluble associative latex thickeners with hydrophobic multi-phenyl groups were prepared with methacrylic acid, ethyl acrylate, diallyl phthatale and varying amount of a functional monomer, triphenylethyl phenoxy polyoxyethylene ether methacrylate （SEM-25）, through emulsion polymerization using a semi-batch process. Thickener latexes of different SEM-25 contents were diluted to different solids, light transmittance and viscosity variations with pH were followed. It was found that light transmittance of the thickener latex sharply increased with varied pH from 6 to 7 due to solubilization of the thickener polymer, which was followed by a plateau region once the thickener latex turned into an aqueous polymer solution. For all latex thickeners, a maximum in viscosity was observed with pH increase. It was revealed that, in order to have a high thickening performance, the solids in the latex thickeners should be kept at an adequate level, equal to or higher than 0.5 wt% regardless of their SEM-25 contents. By comparing the properties of the latex thickeners of different SEM-25, it was observed that the thickener with 1.1 wt% of SEM-25 displayed the lowest viscosity; whereas the one with 5.0 wt% of SEM-25 performed equally to that free of SEM-25; and the thickener with 12 wt% SEM-25 manifested a highest viscosity, providing that solids in the latex thickeners were kept at 0.65 wt% or higher. The experiments were then carried out with the same latex thickeners with varied shearing rate. It was seen that the latex thickener with 5.0 wt% and 12 wt% of SEM-25 outperformed SEM-25 free sample in thickening in all tested shearing range; while the one with 1.1 wt% of SEM-25 showed the lowest thickening effect among all thickener latexes at all tested shearing rates. Finally, 4 latex thickeners, with 0 wt%, 1.1 wt%, 5.0 wt% and 12 wt% of SEM-25 respectively, were separately blended into an aliquot of St-BA （styrene-butyl acrylate） latex of 30 wt% solids. Rheology of the compounded latex was tested. Results showed

关 键 词：SEM-25功能单体 缔合型增稠剂 疏水改性碱溶性乳液 粘度 

分 类 号：TQ630.49[化学工程—精细化工]