Construction of epoxy resin with enhanced flame retardancy, mechanical properties, and satisfactory transparency based on a novel bi‐ DOPO and hydrogen‐bonding network

• Published in: Journal of applied polymer science 2024-10, Vol.142 (4)
• Main Authors: Lin, Xiaoling, Xiao, Xingzhen, Li, Dingsi, Wang, Yonghui, Chen, Xinrong, Zhong, Wei, Lan, Jiashui, Zhang, Simeng, Zhang, Huagui, Chen, Mingfeng
• Format: Article
• Language: English
• Subjects: Enthalpy; Epoxy resins; Flame retardants; Heat release rate; Hydrogen; Impact strength; Light transmittance; Mechanical properties; Tensile strength
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.56415

Establishment of high‐performance epoxy resin with satisfactory fire safety, mechanical properties, and excellent transparency is urgently desirable, but still remains significant challenges. Herein, a super‐tough yet high flame retardant epoxy resin (EP/BTD) was designed and prepared by incorporating bi‐DOPO structure and hydrogen‐bonding networks. Although the phosphorus content was only 0.69 wt% (10 wt% of bi‐DOPO flame retardant [BTD]), EP/BTD‐10 showed a high limiting oxygen index value (33.4%), satisfactory UL‐94 rating (V‐0), and good heat suppression ability (total heat release [THR] and peak heat release rate [PHRR] reduced to 29.0% and 42.2%, respectively). Furthermore, the flame retardant mechanism of EP/BTD was illustrated and attributed to dual‐phase fire‐retardant effect. Additionally, EP/BTD‐7.5 featured notably mechanical properties, of which the tensile strength, elongation at break and impact strength increased by 44.6%, 40.0%, and 232.6%, respectively, due to hydrogen‐bonding network and π–π interaction. More importantly, EP/BTD maintained high visible light transmittance and excellent UV‐blocking properties. In summary, this work provided a guidance for the development of high‐performance epoxy resin and was expected to expand the practical applications.