Novel Dichloronaphthalene Diamine‐Based Curing Agent for Epoxy Resins: Synthesis, Properties, and Preliminary Applications

ABSTRACT A high‐purity (98.5%) naphthylamine‐based curing agent, 2,6‐dichloronaphthalene‐1,5‐diamine (DCNDA), was successfully synthesized through the electrophilic substitution reaction of 1,5‐naphthalene diamine with N‐chlorosuccinimide. When combined with AFG‐90MH resin, the resulting DCNDA‐cured system displays favorable curing characteristics with a broad processing window and an extensive curing temperature range. After a two‐stage process: 150°C for 2 h followed by 180°C for 2 h, the cured resin exhibits outstanding thermal stability, with a glass transition temperature ( T g ) reaching 150°C and a 5% weight loss decomposition temperature ( T d5 ) of 254°C, demonstrating its potential for high‐performance applications.