Zhang Yi
Department of Biology and Chemical Engineering, Shandong Vocational College of Science & Technology Weifang 261053 China
RSC Adv. 2021 Oct 27;11(55):34849-34859. doi: 10.1039/d1ra06116j. eCollection 2021 Oct 25.
In this study, a flame retardant agent, called PEDSCD, is synthesized through a polycondensation reaction. PEDSCD is a chemically expanded phosphorus-containing flame retardant, which is introduced in epoxy resin (EP) to improve its flame retardancy. The molecular structure and thermal stability of PEDSCD are characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and thermogravimetric analysis, and EP/PEDSCD composites are investigated in detail. EP/PEDSCD exhibits good stability and flame retardancy. These properties are attributed to the triazine structure introduced into the flame retardant system. The triazine structure starts to decompose at a lower temperature and also reacts with the phosphorus element to form P[double bond, length as m-dash]N-, which increases the viscosity of the melt. This inhibits the generation of smoke and reduces the peak of heat release. PEDSCD shows good thermal stability and low flammability. Further, the weight loss from 500 to 800 °C is only 16 wt%, and the residual mass at 800 °C is 32 wt%. With the addition of PEDSCD, the flame retardant quality of the EP/PEDSCD composites is gradually enhanced, and the carbon residue becomes denser, which isolates the heat transfer and inhibits the volatilization of flue gas. The limited oxygen index (LOI) value of 27% and a vertical burning V-0 rating are achieved when PEDSCD is used in combination with ammonium polyphosphate (APP). The cone calorimeter test shows that the peak heat release rate is reduced by 29% and low gas content is generated, which verifies that the combination of PEDSCD and other phosphorus-containing flame retardants exhibits significantly enhanced flame-retardant properties. PEDSCD exhibits a charring and barrier effect in the condensation phase. Overall, using basic characterization and flame retardancy testing, it is proved that PEDSCD exhibits good flame retardancy when added to EP.
在本研究中，通过缩聚反应合成了一种名为PEDSCD的阻燃剂。PEDSCD是一种化学膨胀型含磷阻燃剂，将其引入环氧树脂（EP）中以提高其阻燃性。通过核磁共振、傅里叶变换红外光谱和热重分析对PEDSCD的分子结构和热稳定性进行了表征，并对EP/PEDSCD复合材料进行了详细研究。EP/PEDSCD表现出良好的稳定性和阻燃性。这些性能归因于引入阻燃体系中的三嗪结构。三嗪结构在较低温度下开始分解，并且还与磷元素反应形成P=N-，这增加了熔体的粘度。这抑制了烟雾的产生并降低了热释放峰值。PEDSCD表现出良好的热稳定性和低可燃性。此外，500至800℃的重量损失仅为16wt%，800℃时的残余质量为32wt%。随着PEDSCD的添加，EP/PEDSCD复合材料的阻燃质量逐渐提高，炭渣变得更致密，这隔离了热传递并抑制了烟气的挥发。当PEDSCD与聚磷酸铵（APP）组合使用时，极限氧指数（LOI）值达到27%，垂直燃烧达到V-0等级。锥形量热仪测试表明，热释放峰值速率降低了29%，产生的气体含量较低，这证明PEDSCD与其他含磷阻燃剂的组合表现出显著增强的阻燃性能。PEDSCD在凝聚相中表现出炭化和阻隔作用。总体而言，通过基本表征和阻燃性测试，证明了PEDSCD添加到EP中时表现出良好的阻燃性。
