气凝胶
材料科学
聚氨酯
流变学
复合材料
异氰酸酯
聚合物
粘度
基质(化学分析)
复合数
动态力学分析
模数
化学工程
工程类
作者
Paula Cimavilla‐Román,S. Pérez-Tamarit,Anja Vananroye,Paula Moldenaers,Miguel Ángel Rodríguez‐Pérez
标识
DOI:10.1016/j.eurpolymj.2022.111398
摘要
The incorporation of silica aerogel particles into the isocyanate used to prepare Rigid Polyurethane composite foams drastically modifies its rheological behaviour. The isocyanate changes from being a Newtonian fluid of constant viscosity (0.3 Pa s at 25 °C) to a non-linear power-law material with complex viscosity decreasing from 104 to 101 Pa s with a slope −1 versus frequency. The change in response is caused by the formation of a percolated network of particles at contents above 2.5 wt% of aerogel. Moreover, the addition of aerogel significantly slows down the modulus-build up kinetics and vitrification of the matrix by approximately 4.5 min with every 1 wt% of aerogel added. For the foam with 3.0 wt% of aerogel, the combination of high viscosity at early reaction times coupled with the slow modulus build-up impedes the drainage which leads to a decrease in the fraction of material in the struts of the matrix.
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