Economical and environment-friendly synthesis of a novel hyperbranched poly(aminomethylphosphine oxide-amine) as co-curing agent for simultaneous improvement of fire safety, glass transition temperature and toughness of epoxy resins
Economical and environment-friendly synthesis of a novel hyperbranched poly(aminomethylphosphine oxide-amine) as co-curing agent for simultaneous improvement of fire safety, glass transition temperature and toughness of epoxy resins
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经济环保地合成新型超支化聚氨甲基氧化膦胺作为共固化剂，同时提高环氧树脂的防火安全性、玻璃化转变温度和韧性
DOI：
10.1016/j.cej.2017.04.070
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发表时间：
2017-08-15
影响因子：
15.1
通讯作者：
Hu, Yuan
中科院分区：
文献类型：
--
作者：
Ma, Chao;Qiu, Shuilai;Hu, Yuan
环氧树脂本身就具有易燃性和脆性。为了提高其耐火性或韧性，人们采用了各种方法，但玻璃化转变温度(T-g)总是随之恶化。本文以三羟甲基膦(THP)为原料，通过氧化前的α-氨甲基化反应合成了一种新型的超支化聚(氨甲基膦氧胺)(HPAPOA)。以四(羟甲基)硫酸膦和氢氧化钡为原料制备THP，避免了合成过程中复杂的提纯过程。当HPAPOA作为环氧树脂的共固化剂时，由于交联度的增加和多种增韧机理，提高了环氧热固性树脂的玻璃化转变温度和冲击强度。同时，防火安全包括阻燃、抑烟和降低毒性(增加1.0wt除外)得到提高。凝聚相阻燃机理为提高成炭率，保护和阻挡生成的炭层和气相中含磷的HPAPOA的释放。当加入3.0wt%的HPAPOA时，环氧热固性树脂达到了垂直燃烧的V-0等级，极限氧指数为30.7%。阐明了吹扫对提高垂直燃烧等级的影响。环氧树脂体系的固化反应活性略有变化，反应活化能有所提高。环氧热固性树脂的热分解温度降低。当HPAPOA含量为2.0wt%时，拉伸和弯曲性能有所改善，其他含量的拉伸和弯曲性能略有下降。实用化的HPAPOA改性环氧热固性树脂克服了明显的缺点，具有较高的玻璃化转变温度，可用于工业高性能应用。(C)2017年，由爱思唯尔出版。
Epoxy resins inherently suffer flammability and brittleness. Various approaches have been used to improve their fire safety or toughness, however, glass transition temperature (T-g) is always deteriorated concomitantly. Herein, a novel hyperbranched poly(aminomethylphosphine oxide-amine) (HPAPOA) was synthesized from alpha-aminomethylation reaction of trihydroxymethylphosphine (THP) with piperazine before oxidation. THP was prepared from tetrakis(hydroxymethyl)phosphonium sulfate and barium hydroxide to avoid complex purification in the synthesized process. When HPAPOA was utilized as co curing agent for epoxy resins, T-g and impact strength of epoxy thermosets are improved due to the increased cross-linking density and the multiple toughening mechanisms. Simultaneously, fire safety include flame retardancy, smoke suppression and toxicity reduction is raised (except 1.0 wt added). The condensed phase flame retardant mechanism is verified as increased char yield and protective and barrier effect of the formed char layer and the gas phase for release of phosphorus-containing species of HPAPOA. With as low as 3.0 wt% HPAPOA incorporated, epoxy thermoset achieved vertical burning V-0 rating with a limited oxygen index of 30.7%. The blowing-out effect for upgradation of vertical burning rating is elucidated. Moreover, the curing reactivity of epoxy systems is slightly changed and the reaction activation energy is elevated. The thermal decomposition temperature of epoxy thermoset diminishes. With 2.0 wt% HPAPOA added, tensile and flexural properties are improved and those with other contents are slightly depressed. The practical HPAPOA modified epoxy thermosets with obvious disadvantage conquered and higher T-g can be used in industries for high-performance applications. (C) 2017 Published by Elsevier B.V.