A liquid phosphorus-containing imidazole derivative as flame-retardant curing agent for epoxy resin with enhanced thermal latency, mechanical, and flame-retardant performances

Siqi Huo; Shuang Yang; Jun Wang; Jianwen Cheng; Qianqian Zhang; Yefa Hu; Guoping Ding; Qiaoxin Zhang; Pingan Song

doi:10.1016/j.jhazmat.2019.121984

A liquid phosphorus-containing imidazole derivative as flame-retardant curing agent for epoxy resin with enhanced thermal latency, mechanical, and flame-retardant performances

J Hazard Mater. 2020 Mar 15:386:121984. doi: 10.1016/j.jhazmat.2019.121984. Epub 2019 Dec 26.

Authors

Siqi Huo¹, Shuang Yang², Jun Wang³, Jianwen Cheng³, Qianqian Zhang³, Yefa Hu⁴, Guoping Ding⁴, Qiaoxin Zhang⁴, Pingan Song⁵

Affiliations

¹ School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430070, People's Republic of China; Center for Future Materials, University of Southern Queensland, Toowoomba 4350, Australia.
² School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, People's Republic of China; Institute of Advanced Material Manufacturing Equipment and Technology, Wuhan University of Technology, Wuhan 430070, People's Republic of China. Electronic address: ysfrp@whut.edu.cn.
³ Institute of Advanced Material Manufacturing Equipment and Technology, Wuhan University of Technology, Wuhan 430070, People's Republic of China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
⁴ School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, People's Republic of China; Institute of Advanced Material Manufacturing Equipment and Technology, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
⁵ Center for Future Materials, University of Southern Queensland, Toowoomba 4350, Australia. Electronic address: pingansong@gmail.com.

PMID: 31896008
DOI: 10.1016/j.jhazmat.2019.121984

Abstract

The development of phosphorus-containing flame retardants combining good compatibility with matrix, low curing temperature, and mechanically reinforcing effect has remained a major challenge. Herein, we reported the synthesis of a liquid flame-retardant curing agent (DA) via the nucleophilic substitution between diphenylphosphinic chloride and 1-(3-aminopropyl)-imidazole (AI). DA exhibited good blending and latency towards epoxy resin (EP) at room temperature. According to DSC studies, DA could rapidly cure EP at moderate temperature. Compared with EP/AI sample, EP/DA samples displayed comparable or higher glass transition temperature (T_g) and enhanced mechanical properties due to the introduction of rigid diphenylphosphinyl group and improved cross-linking density. Moreover, DA improved the flame-retardant performances of EP thermoset. For instance, the LOI and UL94 rating of EP/DA-16 sample achieved 37.2 % and V-0, respectively. In addition, the peak of heat release rate (PHRR), average of heat release rate (AHRR), fire growth rate (FIGRA), and total heat release (THR) for EP/DA-16 sample reduced by 32 %, 42 %, 28 % and 27 % in comparison to EP/AI sample, respectively. DA was characterized by its good compatibility with EP, moderate curing temperature, fast curing rate, suitable thermal latency, mechanical reinforcing and flame-retardant effects, and thus it had a broad application prospect in various industrial fields.

Keywords: Epoxy resin; Flame retardancy; Liquid phosphorus-containing imidazole; Mechanical properties; Thermal latency.

Publication types

Research Support, Non-U.S. Gov't