Synthesis of a novel cross‐linked organophosphorus‐nitrogen containing polymer and its application in flame retardant epoxy resins
Synthesis of a novel cross‐linked organophosphorus‐nitrogen containing polymer and its application in flame retardant epoxy resins
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DOI：
10.1002/fam.2349
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发表时间：
2016-10
影响因子：
1.9
通讯作者：
Miaojun Xu;Xu Li;Bin Li
中科院分区：
文献类型：
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作者：
Miaojun Xu;Xu Li;Bin Li
通过尿素与硫酸四羟甲基磷的缩聚反应合成了一种新型交联有机磷-氮聚合阻燃添加剂聚（脲四亚甲基硫酸磷），定义为PUTMPS。其化学结构通过傅里叶变换红外（FTIR）光谱、13C和31P固态核磁共振得到了很好的表征。将合成的PUTMPS与固化剂间苯二胺共混到环氧树脂中制备阻燃环氧树脂热固性材料。通过极限氧指数（LOI）、垂直燃烧试验（UL-94）、锥形量热仪测量和热重分析（TGA）测试研究了PUTMPS对EP/PUTMPS热固性材料的阻燃性和热降解行为的影响。分别通过扫描电子显微镜和 X 射线光电子能谱 (XPS) 研究了固化环氧树脂的炭残留物的表面形貌和化学成分。通过将样品放入70℃蒸馏水中168小时来评价环氧树脂热固性材料的耐水性能。结果表明，EP/12 wt% PUTMPS 热固性材料成功通过 UL-94 V-0 可燃性评级，LOI 值达到 31.3%。 TGA结果表明，PUTMPS的加入促进了环氧树脂基体的分解和成炭提前，从而使环氧树脂热固性材料在高温下具有更高的成炭率和热稳定性。对环氧树脂热固性材料残炭的形貌结构和XPS分析表明，PUTMPS有利于燃烧过程中材料表面形成充分、致密、均匀且富含阻燃元素的炭层，阻止热传递和扩散，限制可燃气体的产生，抑制烟雾的排放，从而降低热释放率和产烟率。经过耐水测试，EP/12 wt% PUTMPS 热固性材料仍保持优异的阻燃性。版权所有 © 2015 约翰·威利父子有限公司
A novel cross‐linked organophosphorus–nitrogen polymetric flame retardant additive poly(urea tetramethylene phosphonium sulfate) defined as PUTMPS was synthesized by the condensation polymerization between urea and tetrahydroxymethyl phosphonium sulfate. Its chemical structure was well characterized by Fourier transform infrared (FTIR) spectroscopy, 13C and 31P solid‐state nuclear magnetic resonance. The synthesized PUTMPS and curing agent m‐phenylenediamine were blended into epoxy resins to prepare flame retardant epoxy resin thermosets. The effects of PUTMPS on fire retardancy and thermal degradation behavior of EP/PUTMPS thermosets were investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter measurement, and thermalgravimetric analysis (TGA) tests. The surface morphologies and chemical compositions of char residues for cured epoxy resins were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS), respectively. Water resistant properties of epoxy resin thermosets were evaluated by putting the samples into distilled water at 70°C for 168 h. The results demonstrated that the EP/12 wt% PUTMPS thermosets successfully passed UL‐94 V‐0 flammability rating and the LOI value reached 31.3%. The TGA results indicated that the incorporation of PUTMPS promoted epoxy resin matrix decomposed and char forming ahead of time, which led to a higher char yield and thermal stability for epoxy resin thermosets at high temperature. The morphological structures and analysis of XPS for the char residues of the epoxy resin thermosets shown that PUTMPS benefited to the formation of a sufficient, more compact, and homogeneous char layer with rich flame retardant elements on the materials surface during burning, which prevented the heat transmission and diffusion, limited the production of combustible gases, inhibited the emission of smoke, and then led to the reduction of the heat release rate and smoke produce rate. After water resistance tests, EP/12 wt% PUTMPS thermosets still remained excellent flame retardancy. Copyright © 2015 John Wiley & Sons, Ltd.