Room Temperature Oxalic Acid-Catalyzed, Ambient Pressure Dried, and Cost-Effective Synthesis of Polybenzoxazine Aerogels for Thermal Insulation

The quest for ambient pressure dried, cost-effective, and environmentally friendly synthesis technology has been continuously pursued throughout the aerogel research process. Herein, oxalic acid catalyst is used to synthesize a series of polybenzoxazine (PBZ) aerogels through room temperature ring-opening polymerization and ambient pressure drying technique based on phenol-4,4 '-diaminodiphenylmethane benzoxazine (PH-mda) monomer. The resultant PBZ aerogels with a microstructure of 3D nanoporous network exhibit a low density of 0.13-0.36 g cm(-3)and relatively low thermal conductivities of 0.0323 (10(5) Pa) and 0.0119 W m(-1) K-1(10 Pa), respectively. Remarkably, PBZ aerogels possess excellent compressibility (the maximum strain can be more than 80%), high compressive modulus, and specific modulus because of their rough skeleton structure. Taking advantage of the simple synthetic route, easily scaled-up, lightweight, low thermal conductivity, and excellent mechanical property, such PBZ aerogels may have great potential to serve as a new material for energy-efficient buildings and the other thermal insulating field.