Facile fabrication of mechanical monolithic polyamide aerogels via a modified sol–gel method

Abstract

The good-formability polyamide (PA) aerogel via a modified sol–gel technology was facilely fabricated by using melamine and isophthaloyl chloride with the acid-binging agent followed by CO2 supercritical drying. The synthesis procedure was straightforward and simple, relying on no nitrogen-based protective atmosphere. The influences of various parameters, such as the amount of acid-binging agent, reaction temperature and precursor concentration, on the aerogel structure were discussed. The structural properties of PA aerogels were characterized by the scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller methods and Fourier transform infrared spectroscopy. The results indicated that the PA aerogel had a typical three-dimensional porous structure. Due to the moderate mechanical property of the PA aerogel, the aerogel had potential for the use in construction and building materials. We reported that the good-formability polyamide (PA) aerogel via a modified sol–gel technology was facilely fabricated by using melamine and isophthaloyl chloride with the acid-binging agent followed by CO2 supercritical drying. The synthesis procedure was straightforward and simple, relying on no nitrogen-based protective atmosphere. The dimethylacetamide (DMAC) as the acid-binging agent could indeed remove the hydrochloric acid to accelerate the cross-linking degree of the PA prepolymer and improve the formation of a fine porous structure of the PA aerogel. Thus, the specific surface area of the PA aerogel after the addition of acid-binging agent could be enhanced as high as 391 m2/g, higher than that (282 m2/g) of the one without the DMAC. Furthermore, it also showed the influences of various parameters, such as reaction temperature and precursor concentration, on the aerogel structure. According to the structure analysis, the results indicated that the PA aerogel had a typical three-dimensional structure with various porous size. Due to the moderate mechanical property, the PA aerogel had potential for use in construction and building materials.