醚基硅溶胶和多异氰酸酯反应制备SiO_2原位增强聚氨酯硬泡及其增强机理

Preparation and Mechanism of In-Situ Reinforced Rigid SiO_2/Polyurethane Foam Prepared from Polyether-Based Silica Sol and Polyisocyanate

应用自制界面剂控制硅溶胶粒径,得到一种以聚醚多元醇为分散介质的聚醚基硅溶胶,以此硅溶胶与多异氰酸酯(PAPI)反应,制备了二氧化硅(SiO_2)原位增强聚氨酯(PU)硬泡。通过发泡反应特性测试、电子显微镜观察泡孔结构及PU硬泡的压缩强度测试,研究了原位反应生成的SiO_2对PU泡孔结构的影响,并结合数学模拟计算结果,探讨了SiO_2对PU硬泡的增强机理。结果表明,界面剂对硅溶胶有较强稳定作用,原位反应生成的SiO_2在PU发泡过程中具有良好的异相成核作用,且这种作用导致的泡孔均匀性与泡孔壁厚增加是SiO_2增强PU硬泡的主要原因。当聚醚基硅溶胶浓度为8%时(以SiO_2含量计),制备出的PU硬泡的泡孔较均匀,压缩强度较未增强的PU硬泡提升了约50%。

A polyether-based silica sol was prepared from self-made surfactant and silica sol. This polyether-based silica sol reacted with polyisocyanate(PAPI) to prepare in-situ reinforced rigid SiO2/PU foams. In order to study effects of SiO2 on the cell structure of polyurethane (PU) and the reinforce mechanism, the cell structure was observed by scanning electron microscope(SEM) and a mathematical model was used. The results show that the surfactant has a strong stabilizing effect on the silica sol, and the SiO2 made by in-situ reaction has a good heterogeneous nucleation during the PU foaming process. When the content of the polyether-based silica sol is 8%(calculated by the SiO2 content), the prepared PU foam presents a uniform cell size distribution, and the compressive strength is increased by about 50% compared with that of the non-silica sol.