水分散有机硅-聚氨酯嵌段共聚物/蒙脱土纳米复合材料的制备与性能

Preparation and Properties of Waterborne Polysiloxaneurethane/Clay Nanocomposite

以自制的端氨烃基聚二甲基硅氧烷低聚物(NS)作扩链剂,制备了水分散有机硅-聚氨酯嵌段共聚物/蒙脱土(WPSUR/MMT)纳米复合材料。广角X-射线衍射谱图与透射电镜分析表明,MMT插层聚醚后,其有序结构被破坏,无规剥离分散在WPSUR基体中,得到了剥离型的WPSUR/MMT纳米复合材料。实验发现,随着体系中MMT用量的提高,水分散液液滴粒径及多分散性未发生明显变化,表观黏度增大;相同MMT用量下,采用NS作扩链剂时水分散液液滴的粒径大于采用小分子作扩链剂时,表观黏度较大。MMT的引入改善了WPSUR/MMT膜的力学性能,当MMT质量分数为1%时,WPSUR/MMT膜的拉伸强度和断裂伸长率较WPSUR分别提高了22.8%与9.6%,达到了既增强又增韧的效果;NS与MMT均可提高WPSUR膜的耐热性能,较之未添加MMT的WPSUR膜,WPSUR/MMT(3%)膜的热失重曲线第二阶段的峰值温度提高了20℃。

A novel nanocomposite aqueous dispersion composed of waterborne polysiloxane - urethane/ montmorillonite （WPSUR/MMT） was synthesized by self-made amino-terminated polydimethylsiloxane （NS） as chain extender. Wide angle X - ray diffraction （WXRD） and transmission electron microscopy （TEM） showed that MMT＇s ordered structure was destroyed after its intercalation with polyether, and random strips were scattered in WPSUR. Therefore, stripped type WPSUR/MMT nanocomposites were obtained. The experimental results showed that with the increase of the amount of MMT, the particle size of aqueous dispersion increased, apparent viscosity increased. With the same amount of MMT, the particle size of aqueous dispersion with NS as chain extender is lager than that with micromolecule as chain extender, its apparent viscosity is high. The introduction of MMT significantly improved the mechanical properties of WPSUR/MMT film. When the mass fraction of MMT was 1% , the tensile strength and elongation at break of WPSUR/MMT film increased 22.8% and 9.6% compared to blank WPSUR, reinforcing and toughening the WPSUR. Both NS and MMT improved the heat resistance of WPSUR film when NS was used as chain extender. The weight loss peak temperature in the second phase of WPSUR/MMT （3%） film increased by 20℃.