Wood/polyimide composite via a rapid substitution compositing method for extreme temperature conditions

Abstract

Wood is a common-sense thermostable construction material, but the decrease in its structural stability and mechanical strength due to the degradation of lignin and hemicelluloses limits its practical applications in extreme environments. Here, we synthesize a high-performance wood/polyimide composite via the partial substitution of lignin and hemicellulose with super thermostable polyimide. This method involves the rapid partial removal of lignin and hemicellulose in only 3 min using microwave-assisted deep eutectic solvent (DES) pretreatment and subsequent impregnation of polyimide into the pretreated wood. The microwave-assisted DES pretreatment greatly reduced the processing time for lignin and hemicellulose extraction, while preserving the natural cellular scaffold of wood and opening more channels for polyimide infiltration. The obtained wood/polyimide composite showed a 17% improved Young's modulus and a 63% higher dynamic storage modulus than natural wood. The temperature of the first maximum decomposition rate of the wood/polyimide composite significantly increased to 290 °C due to the infiltration of the thermostable polyimide. Furthermore, the wood/polyimide composite exhibited a smoke suppression property (33% decrease), and the time to produce smoke was delayed by 200 s. Our work provides a rapid pretreatment method for wood and a substitution compositing method to produce wood-framed polyimide composites with excellent thermostability.