A high-performance flame retardant liquid synthesized on the basis of DOPO hydrolysis products avoids the defects of DOPO

• Published in: Polymer degradation and stability 2025-02, Vol.232, Article 111116
• Main Authors: Liu, Peifeng, Wang, Xiang, Jiang, Xingwu, Huang, Jinzheng, Dong, Zhenzhen, Miao, Shicheng, Huo, Siqi
• Format: Article
• Language: English
• Subjects: DOPO; Epoxy resin; Flame retardant; HPPA; Overall properties
• ISSN: 0141-3910
• DOI: 10.1016/j.polymdegradstab.2024.111116

•During combustion, due to the excellent catalytic carbonization of PPOA, HPPA is dehydrated to re-form DOPO, thus providing both gas-phase and condensed-phase flame retardancy.•The high phosphorus content of DP up to 17.5 wt% enables EP to achieve high flame retardancy with small additions, without damaging the overall properties of EP due to low additions.•HPPA modified flame retardant DP is transparent colorless liquid, easy to store, transport and process. It was first proposed to use 2-(2-hydroxyphenyl) phenyl phosphonic acid (HPPA), which is hydrolysis product of DOPO, has a structure more similar to EP, to replace DOPO in the preparation of flame retardant, and finally synthesized a highly efficient liquid flame retardant DP based on HPPA, the theoretical phosphorus content of DP is up to 17.5wt%, so EP can achieve excellent flame retardant/inhibit combustion effect with a small amount addition of DP. For example, the LOI of EP/DP6.0 is increased to 41.2 % and reaches the V-0 rate of UL-94, the PHRR and THR are reduced by 52.4 % and 45.2 % respectively, in addition, the addition of DP in small quantities does not destroy the overall performance of EP, maintains and improves the excellent mechanical and thermal properties of epoxy resin as a whole, and DP has excellent curing promoting effects, meeting the processing and use requirement of high performance EP. It is better than DOPO overall and has good application prospects. [Display omitted]