Manufactory and Properties of Poly(<i>p</i>-Phenylenebenzobisoxazole) Aerogels Prepared by a Simple Freeze-Drying Procedure

Aerogels based on organic high performance fibers have been attracted great attention due to its excellent thermal and mechanical properties. Here, PBO nanofiber aerogel were prepared from the super-fiber PBO through a top-down process with a sol-gel process and a simple freeze-drying process, followed by thermal cross-linking. The prepared aerogel has a small volume shrinkage, a high specific surface area of 168.9 m 2 /g and a small pore diameter of 1.356 nm. Because of its 3D porous structure, it results in a low density of 6 to 30 mg/cm 3 and a high porosity (98%). The aerogel retains the molecular structure of PBO at the same time, which gives it initial thermal decomposition temperature up to 500 °C and a superior fire-retardant capability. PBO aerogel possesses good compressive properties with a yield stress of 0.44MPa at 80% strain and an elasticity modulus of 1.98 MPa which is higher than SiO 2 and cellulose aerogel reported.