星型水性聚氨酯缔合型增稠剂的合成及其性能

Synthesis and Properties of Star-shaped Waterborne Polyurethane Associative Thickener

利用异佛尔酮二异氰酸酯(IPDI)与聚乙二醇(PEG-6000)反应制备预聚体,以丙三醇和三羟甲基丙烷作为扩链剂,十六醇为封端剂,制备了星型结构的水性聚氨酯缔合型增稠剂(SHEUR)。采用FTIR和GPC对SHEUR分子结构进行了表征;利用黏度计和旋转流变仪对SHEUR水溶液的黏度、SHEUR对乳液增稠后的黏度以及SHEUR水溶液的流变性进行了分析,并与合成的线型结构水性聚氨酯缔合型增稠剂(LHEUR)进行对比,考察了不同结构的增稠剂分子对其增稠性能的影响。结果表明:SHEUR增稠效果比LHEUR好;向丙烯酸乳液中加入增稠剂的质量分数为1%时,以三羟甲基丙烷为扩链剂的SHEUR-a增稠后的黏度为61 440 m Pa·s,而以1,6-己二醇为扩链剂的LHEUR-b增稠后黏度仅为202 m Pa·s;低剪切时,SHEUR黏度维持在较高水平,剪切速率大于100 s-1后,SHEUR出现剪切变稀现象。对SHEUR流变性和乳液增稠后粒径的测定结果表明,所合成的SHEUR具有良好的触变性。

A series of star-shaped waterborne polyurethane associative thickener（SHEUR） were prepared with polyethylene glycol（PEG-6000） and isophorone diisocyanate（IPDI） as raw materials,glycerol and 2-ethyl-2-（hydroxymethyl）-1,3-propanediol（TMP） as chain extenders,and hexadecanol as an end-capping reagent.The molecular structure of the obtained SHEUR was characterized by means of FTIR and GPC.The viscosity of SHEUR water solution,the emulsion thickened by SHEUR and the rheological property of SHEUR aqueous solution were studied by viscometer and rotational rheometer.Meanwhile,the effects of thickeners with different structures on the thickening properties were investigated.The experimental result indicated that the thickening effect of the star-shaped SHEUR was better than that of the linear HEUR.When 1% thickener was added into acrylic emulsion,the viscosity of the SHEUR-a with trimethylolpropane as chain extender was 61 440 mPa·s,while the viscosity of the LHEUR-b with 1,6-hexanediol was 202 mPa · s.At low shear rate,the viscosity of the SHEUR solution kept at higher levels.But when the shear rate was greater than 100 s^- 1,the SHEUR solution exhibited a behavior of shear-thinning.The rheology behavior of the SHEUR solution and the effect of SHEUR solution on the particle size of acrylic emulsion displayed that the synthetic SHEUR had good thixotropy.