Schiff base derivative flame-retardant endowing epoxy resin with toughness, transparency, and high flame retardancy

• Published in: European polymer journal 2024-06, Vol.214, p.113114, Article 113114
• Main Authors: Han, Linxuan, Hao, Fenghao, Chen, Yajun, Wu, Xiao, Qian, Lijun
• Format: Article
• Language: English
• Subjects: Epoxy resin; Flame retardant performance; Schiff base derivatives; Toughening
• ISSN: 0014-3057
• DOI: 10.1016/j.eurpolymj.2024.113114

[Display omitted] •SMAE was synthesized, and was used as a co-curing agent with DDM to cure EP.•At a 5 % dosage, the LOI value reached 39.7 %, successfully passing UL 94 V-0.•SMAE primarily exerted a blowing-out effect in EP.•The impact strength of 5 %SMAE/EP increased to 14.15 kJ/m2 by 25 % relatively to the pure EP. In this study, a novel phosphorus-containing flame retardant, SMAE, was prepared through a nucleophilic addition of N,N'-bis(salicylidene)ethylenediamine (SAED) and phenyl hypophosphite. SMAE can dissolve well in epoxy resin and provides molecular-level flame retardancy. By using SMAE as a co-curing agent and DDM to cure epoxy resin, EP/SMAE composites with excellent flame retardancy and good mechanical properties were obtained. As the dosage gradually increases, the limited oxygen index (LOI) values continue to rise. At a 5 % dosage, the Limiting Oxygen Index (LOI) value can reach 39.7 % and meet the UL 94 V-0 standard. It is observed that SMAE mainly exerts a blowing-out effect in EP. In addition, the use of SMAE as a co-curing agent can improve the impact strength of EP. The impact strength of 5 % SMAE/EP can reach 14.15 kJ/m2, which is 25 % higher than that of pure EP.