含亚胺结构新型磷-氮协效阻燃化合物的合成及对环氧树脂的阻燃作用

doi:10.11944/j.issn.1000-0518.2020.02.190213

摘要/Abstract

摘要：

采用醛胺缩合反应,以4-(5,5-二甲基-1,3-二氧杂环己内磷酰基)苯甲醛(PCHO)分别与对苯二胺、乙二胺反应合成两种磷酸酯-亚胺双官能化合物阻燃剂(FR:N¹,N⁴-二[4-(5,5-二甲基-1,3-二氧杂环己内磷酰氧基)苯基亚甲基]-1,4-苯二胺(PNB)和N¹,N²-二[4-(5,5-二甲基-1,3-二氧杂环己内磷酰氧基)苯基亚甲基]-1,2-乙二胺(PNE)),研究了FR对4,4'-二氨基二苯砜(DDS)固化双酚A二缩水甘油醚型环氧树脂(DGEBA)体系的阻燃作用及阻燃机理。研究发现FR的引入显著提高了DGEBA/DDS在700 ℃时的残炭率(R_c),同时提升了材料的阻燃性能,其中以乙二胺合成的PNE阻燃性能显著优于以苯二胺合成的PNB。当磷添加质量分数为1.5%时,PNE-1.5/DGEBA/DDS在N₂气下的R_c为35.1%,在空气下的R_c为14.4%,极限氧指数(LOI)为33.2%,并可达阻燃等级UL-94最高阻燃级别V-0级。同时,PNE-1.5/DGEBA/DDS相较于DGEBA/DDS保持了弯曲强度和76%以上的冲击强度,机械性能显著优于PNB-1.5/DGEBA/DDS。通过阻燃机理分析FR在DGEBA/DDS体系中具有凝聚相、气相及磷-氮协效共同作用的阻燃特点。磷酸酯-亚胺双官能团化合物FR对环氧树脂体系具有良好的阻燃作用,其中PNE阻燃效率高、机械性能负面影响小,具有潜在应用价值。

关键词: 亚胺, 磷-氮协效, 阻燃, 环氧树脂

Abstract:

Two novel phosphate-imine bifunctional flame-retardant compounds (FR:N¹,N⁴-bis{[4-(5,5-dimethyl-2-oxide-1,3,2-dioxaphosphinan-2-yl)oxy]benzylidene}benzene-1,4-diamine(PNB); N¹,N²-bis{[4-(5,5-dimethyl-2-oxide-1,3,2-dioxaphosphinan-2-yl)oxy]benzylidene}ethane-1,2-diamine(PNE)) were synthesized via aldehyde amine condensation reaction using 4-(5,5-dimethyl-1,3-dioxygen heterocyclic phosphoryl) benzaldehyde (PCHO), p-phenylene diamine and ethylenediamine as raw materials, respectively. FRs were applied on a bisphenol-A diglycidyl ether type epoxy resin (DGEBA) cured by 4,4'-diaminodiphenylsulfone (DDS) and the flame retarded mechanism was studied. The results showed that the introduction of FR greatly improved the char residues (R_c) of DGEBA/DDS at 700 ℃ and enhanced the flame retardant properties of epoxy resin systems. PNE with ethylene diamine unit presented a better flame retardant performance than PNB with p-phenylene diamine unit. With 1.5% phosphorus content, PNE-1.5/DGEBA/DDS could obtain R_c of 35.1% in nitrogen atmosphere and 14.4 % in air, respectively, and a limiting oxygen index(LOI) value of 33.2%, reaching UL-94 V-0 grade. At the same time, PNE-1.5/DGEBA/DDS maintained the bending strength and more than 76% of the impact strength compared to DGEBA/DDS, which is significantly superior to PNB-1.5/DGEBA/DDS. Analysis of flame retardant results showed that FR presented a comprehensive mechanism of condensed phase, gas phase and phosphorus-nitrogen synergistic effect in DGEBA/DDS system. In conclusion, phosphate-imine bifunctional compounds FR have excellent flame retardancy for epoxy resin systems and have potential applications.

Key words: imide, phosphorus-nitrogen synergy, flame retardant, epoxy resin

游歌云, 冯彬, 范方方, 杨昌杰, 梁聪. 含亚胺结构新型磷-氮协效阻燃化合物的合成及对环氧树脂的阻燃作用[J]. 应用化学, 2020, 37(2): 144-154.

YOU Geyun, FENG Bin, FAN Fangfang, YANG Changjie, LIANG Cong. Synthesis of Phosphorus-Nitrogen Synergistic Flame-Retardant Compounds with Imide Structure and Their Flame Retardant Effect on Epoxy Resin[J]. Chinese Journal of Applied Chemistry, 2020, 37(2): 144-154.

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