In Situ Thermal Cross-Linked Semi-Interpenetrating Polyamide-Imide/Meta-Aramid Micro/Nanofibrous Aerogels for Thermal Insulation

Currently, polymer nanofibrous aerogels suffer from the disadvantages of poor heat resistance and lack of interaction between polymer nanofibers, and it is challenging to fabricate polymer nanofibrous aerogels with excellent elasticity and thermal properties. In this thesis, a bottom-up strategy to form micro/nanofibrous aerogels (MNFAs) by semi-interpenetrating polymer network (Semi-IPN) structure, with flexible meta-aramid (PMIA) nanofibers and rigid polyamide-imide (PAI) microfibers prepared by electrostatic spinning, was reported. The rigid-flexible coupling structure enhanced the aerogels' thermal insulation and mechanical properties, while semi-IPNs endowed the aerogels with excellent structural stability and elasticity. The PAI/PMIA MNFAs also possessed superelastic and pronounced fatigue resistance. The stress retention of the aerogel was 76.6% of the initial value after 200 cycles at 80% strain, producing only 19.8% plastic deformation. Besides, MNFAs have a good thermal insulation property (30.66 mW m–1 K–1), as well as a high thermal decomposition temperature (420.0 °C). Such attractive aerogel materials exhibit excellent prospects in human body thermal protection, equipment protection, etc.