Solvent-Resistant Self-Crosslinked Poly(ether imide)

Poly(ether imide) (PEI) is a high-performance polymer with outstanding thermal stability, mechanical strength, and processability, but a critical drawback of poor solvent resistance. Exposure to solvents including chloroform, dimethylformamide, dichloromethane, and N-methyl pyrrolidone severely compromises the mechanical and thermal performances. Herein, we report a method for preparing thermally crosslinked PEI (X-PEI) from azide-terminated PEI (N-3-PEI-N-3) synthesized via a one-pot diazotization-azidation reaction. X-PEI affords unprecedented solvent resistance unpossessed by conventional PEIs, as well as solution processability unrivaled by counterpart high-performance polymers such as polyimide. The glass transition temperature, storage modulus, and swelling ratio correlate positively with crosslinking density, which is determined by the molar mass and azide concentration of N-3-PEI-N-3. This work advances the chemistry of high-performance polymers. The method is generic and applicable to other engineering polymers.

Automated summary

A method has been developed to prepare thermally crosslinked PEI with improved solvent resistance and solution processability, showing that the glass transition temperature, storage modulus, and swelling ratio of the material correlate positively with crosslinking density.