Polyethersulfone foam with aligned porous structure from frozen solvent templating for high-performance thermal insulation

摘要

Thermal insulation materials play very important roles in many aspects of industry, such as prevention of thermal energy dissipation, protection from high temperature injury, and so on. Herein, we present a strategy for making polyethersulfone (PES) foam with aligned porous and lamellar structures using frozen dimethyl sulfoxide (DMSO) solvent templating method. The effects of concentration, freezing temperature, and inclination angle on the microstructure and properties of PES foams are investigated, among which concentration is the most vital factor. With the decrease of PES solution concentration, thermal insulation performance of PES foams is enhanced, but compression strength is weakened. A lower freezing temperature results in a smaller thermal conductivity coefficient and higher compression strength of PES foams. Inclination angle of freezing mainly affects the growth direction of DMSO crystals and makes thermal conduction deviate from vertical direction, which enhances the thermal insulation performance of PES foam but reduces the compression strength along vertical direction. PES foam prepared from a PES DMSO solution of 7 wt and freezing temperature of - 196 degrees C has a thermal conductivity coefficient of 0.0320 W/(mK) and compression strength of higher than 0.6 MPa. PES foams are flame-retardant and their long-term use temperature can reach 180 degrees C. Consequently, PES foams prepared in this study have great application potential in the field of high-temperature thermal insulation, especially when high compression strength and flame-retardance are required.