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

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 = 1/5 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 gcm- 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.

Automated summary

A simple method for preparing carbon aerogels with superior thermal insulation and mechanical properties was proposed. By adjusting the ratio of HMTA to BPR, the microstructure of the aerogels can be regulated to achieve the desired properties. The obtained carbon aerogels show high compressive strength, low density, and low thermal conductivity, making them a competitive candidate for high-temperature heat insulation materials.