丙烯酸系交联缔合型增稠剂的制备及表征

以甲基丙烯酸（MAA）、丙烯酸乙酯（EA）和亲水性聚氧化乙烯长链末端连有疏水性烷基长链的功能单体（BEM）为原料，采用半连续乳液聚合方法，合成交联剂邻苯二甲酸二烯丙酯（DAP）的质量分数不同的憎水改性交联缔合型增稠剂乳液。测定乳液基本性能，对其碱溶液黏度和透光率随 pH 值的变化进行表征。结果表明，随 NaOH 溶液的加入，乳液的 pH 值升高，其透光率迅速增大达到最大值后基本不变；而其黏度随 pH 值的变化趋势是先迅速升高后缓慢下降；交联剂用量对增稠剂碱溶液的以上行为有明显影响；聚合时加入少量交联剂可提高增稠剂的增稠效果及其抗剪切性能，但其使用量超过单体质量 0. 1%时则会明显降低其增稠效果。

Preparation and Characterization of Cross-Linked Acrylics-Based Associative Thickeners

With methacrylic acid(MAA),ethyl acrylate(EA) and functional monomer bearing hydrophilic ethoxylates terminated by a hydrophobic long alkyl group(BEM) as monomers,hydrophobically modified associative thickener latexes were obtained by semi-batch emulsion polymerization using different amount of dially phthalate(DAP) as the crosslinker.Latex properties were determined.Evolutions of the viscosity and light transmittance with increasing pH in the thickener latexes were followed.With increasing pH by addition of NaOH solution,light transmittance of thickener latexes increase sharply to a maximal value and remains relatively constant afterwards.As to the viscosity,an obvious increase is also observed at the same time with the light transmittance,followed by a slow decline after a peak value.It is found that the behaviors of thickener latexes are closely related to DAP amount used in their preparation.Shearing resistance and thickening performance of the associative latex thickeners are promoted when thickener polymers are slightly crosslinked with a low amount of DAP;Use of DAP amount higher than 0.1% of the monomers leads to the reducing of the thickening performance of the latex thickener.