New flame retardant epoxy resins based on cyclophosphazene-derived curing agents  

作　　者：Zhenwei Miao Dongpeng Yan Xiaodong Wang Xinfang Zhang Wenqi Zhou Munan Qiu Fan Yang Zhanpeng Wu 

机构地区：[1]State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology,Beijing 100029,China [2]College of Chemistry,Beijing Normal University,Beijing 100875,China

出　　处：《Chinese Chemical Letters》2022年第8期4026-4032,共7页中国化学快报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.51773010);the Fundamental Research Funds for the Central Universities(No.XK1802-2)。

摘　　要：To obtain high-efficiency flame retardancy of epoxy resins,a cyclophosphazene derivative tri-(ohenylenediamino)cyclotriphosphazene(3 ACP)was successfully synthesized and used as a curing agent for the thermosetting of an epoxy resin system.The flame retardant properties,thermal stability,and pyrolysis mechanism of the resultant thermosets were investigated in detail.The experiments indicated that the synthesized thermoset achieved a UL-94 V-0 rate under a vertical burning test as well as a limiting oxygen index(LOI)of 29.2%,which was able to reach V-0 even when a small amount of 3 ACP was incorporated.Scanning electronic microscopic observation demonstrated that the char residue of the thermosets was extremely expanded after the vertical flame test.Thermal analysis showed that the samples had a lower initial decomposition temperature when 3 ACP was introduced into the epoxy resin systems.This indicates that the carbonization ability of the thermosets was significantly improved at elevated temperatures.In addition,the incorporation of 3 ACP can effectively suppress the release of combustible gases during the pyrolysis process,and the decomposition of E-44/DDS-3 ACP curing systems also promotes the formation of polyphosphoramides charred layer in the condensed phase.The investigation on the chemical structures of both the gaseous and condensed phase pyrolysis process confirmed the flame-retardant mechanism of the 3 ACP-cured epoxy resins.Therefore,the nonflammable halogen-free epoxy resin developed in this study has potential applications in electric and electronic fields for environment protection and human health.

关 键 词：CYCLOTRIPHOSPHAZENE Curing agent Epoxy resin Flame retardancy Pyrolysis mechanism 

分 类 号：TQ323.5[化学工程—合成树脂塑料工业]