Abstract: Polyimide (PI) staple fiber was used as raw material to prepare non-woven fabrics by spunlace process, in order to be used as the skeleton layer of high-grade chemical protective clothing fabrics. Scanning electron microscope (SEM), electronic fabric strength machine, fabric flame retardant performance tester, etc., were used to study the effects of unit area mass (gram weight) on the microstructure, mechanical properties, flame retardant and chemical stability properties of non-woven fabrics. The results show that the non-woven fabric with a gram weight of 100 g/m2 has good comprehensive properties, and has a longitudinal breaking strength of 448 N and a cross breaking strength of 102 N. It has excellent high/low temperature resistance. There is no continuous combustion and smoldering phenomenon, no melt droplet dripping, and the longitudinal and transverse damage length is less than 2 mm, which has excellent flame retardant performance. It still has good mechanical properties after being soaked in 30% hydrochloric acid, 40% nitric acid and 20% sodium hydroxide. In summary, the preparation of polyimide non-woven fabrics by spunlace process as the skeleton layer of chemical protective clothing has significant advantages.

Key words: polyimide, non-woven fabrics, spunlace process, chemical protection, breaking strength