采用原位聚合法制备酚醛树脂包覆聚磷酸铵微胶囊(MAPP),制备出阻燃性能优良且力学性能较高的EP/MAPP复合材料。采用热重分析法、垂直燃烧法和氧指数法研究了聚磷酸铵(APP)和MAPP阻燃环氧树脂复合材料的热性能及阻燃性能。结果表明,在APP的表面生成了一树脂层,与纯EP和EP/APP环氧树脂复合材料相比,EP/MAPP环氧树脂复合材料的初始分解温度、初始分解温度下的失重、最大失重速率峰值温度、800℃下的残炭量均显著提高。800℃时,EP/MAPP环氧树脂复合材料的残炭率达24.6%,远高于纯EP的17.1%。在MAPP作用下,EP/MAPP复合材料的LOI大于27.5%,垂直燃烧等级达到UL 94 V-0级。添加MAPP微胶囊的EP复合材料的总释热量THR值小于纯EP。相比添加APP,添加MAPP时,EP/MAPP复合材料的拉伸强度、压缩强度和冲击强度均得到提高,尤其是冲击强度高于纯EP,说明EP/MAPP阻燃复合材料的韧性得到提高;而EP/MAPP复合材料的拉伸强度、压缩强度比纯EP仅仅降低5.5%和1.8%。
Microencapsulated ammonium polyphosphate (MAPP) with covering phenol-formaldehyde resin on the surface of ammonium polyphosphate (APP) was prepared by in-situ polymerization.The thermal properties and flame retardancy of pure epoxy resin (EP) and EP/MAPP composites were researched by thermogravimetry,vertical burning and limiting oxygen index.Results showed that the surface of APP was coated by a layer of resin.Compared with EP/APP composites,initial decomposition temperature,temperature of the maximum rate of degradation,and carbon residue at 800℃ of EP/MAPP composites were increased obviously.The carbon residue rate of EP/MAPP composites reaches 24.6%,which was higher than 17.1% of pure EP at 800℃.The limiting oxygen index of EP/MAPP composite was greater than 27.5%,and the vertical burning grade reached UL 94 V-0.The total heat release value of EP composite with MAPP microcapsule was also less than that of pure EP.The tensile strength,compressive strength and impact strength of EP/MAPP composites were improved compared with the addition of APP,and the impact strength was even significantly higher than that of pure EP.That indicated that the toughness of EP/MAPP composites was increased.However,the tensile strength and compressive strength of EP/MAPP composites only decrease by 5.5% and 1.8% compared with that of pure EP respectively.
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