Direct fabrication of poly(p-phenylene terephthalamide) aerogel and its composites with great thermal insulation and infrared stealth

[Display omitted] •The LMW-PPTA solution gelled with the continuous construction of hydrogen bonds.•The PPTA aerogel was prepared by solvent replacement and freeze drying process.•The mechanical properties of PPTA aerogel were reinforced by chopped PPTA fiber.•PPTA/PEG composite material was equipped with superior infrared stealth property. Limited processability of high molecular weight poly(p-phenylene terephthalamide) (PPTA) results in complex, time-consuming, and high-cost procedure of preparing PPTA aerogel. Herein, the chopped PPTA fiber reinforced PPTA aerogel was prepared by spontaneous low molecular weight PPTA (LMW-PPTA) gel. The pore structure and thermal insulation characteristics of composite PPTA aerogel were effectively controlled by varying the concentration of LMW-PPTA solution. Then, the PPTA/phase-change composite (PPTA/PCM) was obtained by dipping process. It was confirmed that the composite PPTA aerogel acquired superior thermal insulation, mechanical properties and great thermal stability above 500 °C. Furthermore, the infrared stealth property of PPTA/PCM composite material was also studied systematically. Significantly, the facile-procedure and lower-cost PPTA aerogel and its composites may have a great potential to be applied as thermal insulation and infrared stealth materials in industrial applications.