酚醛树脂基芳基磷酸酯的合成及其阻燃PC性能研究

Study on Synthesis of Novolac-based Aryl Phosphate and Its Application in Flame Retardant PC

采用二(2,6-二甲基)苯基磷酰氯对线型酚醛酚羟基实行磷酰化封端处理,制备了酚醛树脂基芳基磷酸酯(NDDMPP),将其用于阻燃聚碳酸酯(PC)中。分别用~1H NMR、^(31)P NMR、FTIR、TGA和SEM对NDDMPP的结构、热分解行为以及复合材料燃烧后的炭层形貌进行表征,并测试了复合材料的阻燃性能。结果表明:线型酚醛中约86%的羟基被磷酰化,NDDMPP中的磷含量约为7.54%;NDDMPP在氮气气氛下的起始分解温度超过250℃,显示出良好的热稳定性,可以满足工程塑料的加工温度要求;将NDDMPP应用于阻燃PC树脂,其添加量为10%时,复合材料的氧指数达到32.3%,UL 94阻燃级别提高到V-0级。NDDMPP对PC的阻燃机理在于,NDDMPP可以催化PC的分解过程,使其成炭速率加快,并形成连续致密的膨胀炭层。

A novolac-based aryl phosphate（NDDMPP） flame retardant was synthesized from novolac resin and di（2,6-dimethyl） phenyl phosphoryl chloride. The chemical structure was characterized by fourier transform infrared spectroscopy（FTIR）, ~1H and ^（31） P nuclear magnetic resonance（NMR）. The thermal stability of NDDMPP was studied by thermo gravimetric analysis（TGA）. NDDMPP using as flame retardant for polycarbonate（PC） was evaluated by limiting oxygen index（LOI） and vertical burning test（UL 94）, and relevant mechanisms were studied by using TGA and SEM. The results of 1H NMR, 31 P NMR and FTIR show that 86% of the novolac＇s hydroxy groups is successfully phosphorylated, and the phosphorus content of the NDDMPP achieves 7.54%. Compared to novolac resin, the starting decomposition temperature of NDDMPP increases to over 250℃, and the outstanding thermal stability allows itself to be used in flame retardant polycarbonate（PC）. At 10% loading of NDMPP, PC/NDDMPP composite received a UL 94V-0 rating and a LOI value of 32.3%. The TGA and SEM results show that the NDDMPP can improve the flame retardancy of PC by accelerating the decomposition process and forming a continuous intumescent char layer.