Morphology controlled carbon aerogel with enhanced thermal insulation and mechanical properties: a simple route for the regulated synthesis

Abstract

Abstract A simple route was proposed to prepare size-controlled carbon aerogel with superior thermal insulation and mechanical properties. Boron-modified phenolic resin (BPR) and hexamethylene-tetramine (HMTA) were crosslinked to build three-dimensional network structure initially followed by CO2 supercritical drying and carbonization. In order to regulate the microstructure of BPR aerogels, the best proportion of HMTA to BPR was confirmed as H/P\u202f=\u202f1/5 based on the micromorphology performance in SEM. The interaction between HMTA and BPR was also studied by FTIR spectra, and microstructure evolution of the target product- carbon aerogels were illustrated by SEM technique. SEM patterns indicated that the carbon aerogels maintain a stable porous structure at 1000 °C (carbonization temperature), and pore size distribution were between 321∼612nm based on N2 adsorption-desorption method. The synthesis method is convenient and flexible, permitting a tailor of porous structure, mechanical strength, density and thermal conductivity by adjusting carbonization temperature and time. Consequently, the obtained carbon aerogel with high compressive strength (1.0∼2.3 MPa), low density (0.16∼0.26 g‧cm−3) and low thermal conductivity (0.023∼0.036 W m−l K−1) deserve to be a competitive candidate for high-temperature heat insulation material.