Investigation of the influences of the molecular weights and dosage ratios of polyvinyl alcohol on para‐aramid nanofibers/polyvinyl alcohol composite aerogels

Abstract

AbstractPolymer‐based monolithic composite aerogels with a durable cross‐linked structure were fabricated using polyvinyl alcohol (PVA) and para‐aramid nanofibers (ANFs) as precursors, and supercritical fluid technology as a drying strategy. In order to give a clear insight into ANFs/PVA composite aerogels, we thoroughly investigated the influences of the molecular weights and dosage ratios of PVA on these composite aerogels, and clearly demonstrated the entire process of the evolution of “sol–gel‐aerogel.” The chemical composition, porous nanostructure, porosity, and mechanical performance of the ANFs/PVA composite aerogels were characterized by attenuated total reflectance‐Fourier transform‐infrared spectra (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE‐SEM), nitrogen physical adsorption, and uniaxial compression, respectively. The results revealed the mechanism of the stable composition of ANFs/PVA binary system, and that both the molecular weights and dosage ratios of PVA in the ANFs/PVA composite aerogels have a significant influence on their properties. This work is beneficial to design and fabricate polymer‐based aerogels with desirable chemical and physical characteristics, and the obtained ANFs/PVA composite aerogels with appropriate molecular weight and dosage ratio of PVA possess well‐balanced comprehensive properties, which offer the potential for a wide range of applications.