剪切增稠液微胶囊的制备与性能研究

Preparation and performance investigation of shear thickening liquid microcapsules

本研究以壳聚糖材料为壁材,剪切增稠液(STF)为芯材,通过单凝聚法制备了STF微胶囊(STF MCs)。通过单因素实验研究,确定了微胶囊的制备工艺参数:司盘80(Span 80)与吐温80(Tween 80)作为分散剂,复配比例为3∶1;乳化剂用量为11%,核壳比为2∶1,搅拌速度为600 r/min,反应温度为60℃;体系的油水比为1∶2。在此条件下制得的STF MCs呈较为规整的球形,粒径分布较为均匀,且主要集中在3μm左右。结果表明,碳纳米管的引入有效改善了STF的流变性能。掺杂CNTs的STF体系具有更小临界剪切速率,更快的黏度突变,并且峰值黏度增加近一倍;芯材和微胶囊乳液的红外光谱大部分都一致,表明壳聚糖成功吸附在芯材液滴表面,实现了对STF的包封。壁材对芯材STF起到了保护作用,提升了芯材STF的热稳定性。

In this study,STF microcapsules(STF MCs)were prepared by using a monocoalescence method with chito-san material as a wall material and STF as a core material.The process parameters for the preparation of microcapsules were determined by a single-factor experimental study.Span 80 and Tween 80 were used as dispersants at a mass ratio of 3∶1,the addition amount of emulsifier was determined to be 11 wt%,the mass ratio of core to shell was determined to be 2∶1,the stirring speed was 600 r/min,the reaction temperature was 60℃,and the oil-to-water mass ratio of the sys-tem was 1∶2.The STF MCs produced under these conditions show a relatively regular spherical morphology with a rela-tively uniform distribution centered as a particle size of 3μm.Rheological results indicated that the introduction of carbon nanotubes(CNTs)effectively improved the rheological properties of STFs.The CNTs-doped STF system exhibited a smaller critical shear rate,a faster viscosity transition,and an almost doubled peak viscosity.Infrared spectroscopic re-sults indicated that the infrared spectrum of the microcapsule emulsion was almost consistent with that of the core.This indicated that chitosan was successfully adsorbed on the surface of the core droplets to realize the encapsulation of STFs.Thermogravimetric analysis results indicated the wall material could provide protection for the STF core,thus enhancing its thermal stability.