环酰亚胺化三聚氰胺的制备及其阻燃环氧树脂应用  

Preparation of cycloimidized melamine and application of flame-retardant epoxy resin

作　　者：王晶金 王霞 陈然 杨陈 周昌林 汪磊 WANG Jingjin;WANG Xia;CHEN Ran;YANG Chen;ZHOU Changlin;WANG Lei(College of Materials and Chemical Engineering,Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学材料与化工学院,无机非金属晶态与能源转换材料湖北省重点实验室,湖北宜昌443002

出　　处：《工程塑料应用》2024年第8期7-12,71,共7页Engineering Plastics Application

基　　金：国家自然科学基金项目(22308192);湖北111引智计划项目(2018-19-1)。

摘　　要：三聚氰胺(MEL)因其热稳定性高、耐水解、不易迁移、成炭高、价格低廉等优势,成为阻燃领域关注的热点。然而,六元氮杂环的共轭高化学稳定芳香结构导致其反应活性较低,难以修饰加工。为进一步拓展MEL体系的应用,以MEL、1,2-环己二甲酸酐(HHPA)为原料,制备环酰亚胺化MEL(RFR)并将其应用于环氧树脂(EP)阻燃。通过调控反应原料物质的量比、时间、溶剂、温度等优化RFR的制备工艺条件,采用傅里叶变换红外光谱(FTIR)、核磁共振和元素分析等表征RFR结构;将其加入至EP中,以4,4-二氨基二苯甲烷为固化剂,制得阻燃型EP。利用极限氧指数(LOI)、垂直燃烧测试、万能拉伸试验机、FTIR、热重分析、扫描电子显微镜等手段综合评估改性EP的结构、力学性能、残炭率及阻燃性能。结果表明,当RFR添加质量分数为7.5%时,成炭率相比于未改性EP提升了20.5%,阻燃EP的LOI值达到26.3%,阻燃等级达到UL94 V-1级。从阻燃机理分析,该阻燃剂通过三嗪骨架和环烷基侧基协同发挥了凝聚相和气相阻燃。Melamine(MEL)has become a hot topic in the field of flame retardants due to its advantages such as high thermal stability,hydrolysis resistance,low migration,high carbonization,and low price.However,the highly chemically stable aromatic structure of the conjugated six membered nitrogen heterocycles result in low reactivity and difficulty in further modification.To further expand application of the melamine system,MEL and 1,2-cyclohexanedioic anhydride(HHPA)were used as raw materials to prepare cycloimidized melamine derivative(RFR)and applied in the field of flame-retardant epoxy resin(EP).By adjusting the reaction molar ratio of raw materials,time,temperature,solvent,and other factors,the process conditions for RFR were optimized.Meanwhile,the structure of RFR was characterized by Fourier transform infrared spectrum(FTIR),nuclear magnetic resonance,and elemental analysis.Subsequently,by mixing cycloimidized melamine derivative with EP and thermal curing with 4,4-diaminodiphenylmethane,the flame-retardant EP was fabricated.Finally,comprehensive evaluation of the structure,mechanical properties,residual carbon content,and flame retardancy of flame-retardant EP was conducted by means of limiting oxygen index(LOI),vertical combustion,universal tensile testing machine,FTIR,thermogravimetric analysis and scanning electron microscopy(SEM).The results show that when the mass fraction of RFR is 7.5%,the char-forming rate increase by 20.5%compared to unmodified EP,the LOI of flame-retardant EP reach 26.3%,and the flame retardant grade reach UL 94 V-1 level.From the perspective of flame-retardant mechanism analysis,this flame retardant synergistically exerts both condensed and gas-phase flame retardancy through the triazine skeleton and cycloalkyl side groups.

关 键 词：环酰亚胺 三聚氰胺 环氧树脂 阻燃 成炭 

分 类 号：TQ322.41[化学工程—合成树脂塑料工业]