Synthesis of Hyperbranched Flame Retardants with Varied Branched Chains' Rigidity and Performance of Modified Epoxy Resins

Jingyuan Hu; Liyue Zhang; Mingxuan Chen; Jinyue Dai; Na Teng; Hongchi Zhao; Xinwu Ba; Xiaoqing Liu

doi:10.3390/polym15020449

Synthesis of Hyperbranched Flame Retardants with Varied Branched Chains' Rigidity and Performance of Modified Epoxy Resins

Polymers (Basel). 2023 Jan 14;15(2):449. doi: 10.3390/polym15020449.

Authors

Jingyuan Hu¹, Liyue Zhang¹, Mingxuan Chen^{1

2}, Jinyue Dai^{1

3}, Na Teng¹, Hongchi Zhao², Xinwu Ba², Xiaoqing Liu^{1

3}

Affiliations

¹ Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
² Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China.
³ Key Laboratory of Marine Materials and Related Technologies, Chinese Academy of Sciences, Ningbo 315201, China.

Abstract

To overcome the high flammability and brittleness of epoxy resins without sacrificing their glass transition temperature (T_g) and mechanical properties, three epoxy-terminated hyperbranched flame retardants (EHBFRs) with a rigid central core and different branches, named EHBFR-HB, EHBFR-HCM, and EHBFR-HBM, were synthesized. After chemical structure characterization, the synthesized EHBFRs were introduced into the diglycidyl ether of bisphenol A (DGEBA) and cured with 4, 4-diaminodiphenylmethane (DDM). The compatibility, thermal stability, mechanical properties, and flame retardancy of the resultant resins were evaluated. Results showed that all three EHBFRs could significantly improve the fire safety of cured resins, and 30 wt. % of EHBFRs (less than 1.0 wt. % phosphorus content) endowed cured DGEBA with a UL-94 V-0 rating. In addition, the increased rigidity of branches in EHBFRs could increase the flexural strength and modulus of cured resins, and the branches with appropriate rigidity were also beneficial for improving their room temperature impact strength and T_g.

Keywords: bio-based; epoxy resin; hyperbranched flame retardant; toughness.

Grants and funding

The authors greatly appreciate the financial supports from the National Natural Science Foundation of China (NSFC 52003283, U1909220), the Project of Zhejiang Natural Science Foundation (LQ19E030009), the Zhejiang Analysis and Testing Science and Technology Project (2018C37004, 2022Z160), the Natural Science Foundation of Ningbo City (2019A610181), the Key Project from the Natural Science Foundation of Hebei Province (B2020201072), and the Research Project of Technology Application for Public Welfare of Ningbo City (202002N3122) are greatly appreciated.