季戊四醇芳基膦酸酯的制备及阻燃环氧树脂作用机制

Preparation of Pentaerythritol Aryl Phosphonates and Their Mechanisms in Flame Retardant Epoxy Resins

为了提高环氧树脂(EP)的阻燃性能,以传统的成炭剂季戊四醇(PER)和苯基膦酰二氯(PPDC)为原料,通过亲核取代反应成功制备了阻燃剂季戊四醇芳基膦酸酯(PBPP)。并将其引入到EP基体中,制备了阻燃EP复合材料。通过测试表明,当PBPP的质量分数为6%时,EP/PBPP6复合材料顺利获得了UL-94V-0级,极限氧指数达32.5%,且EP材料的熔滴得到了明显的抑制。热重分析表明,PBPP的引入促进了EP基体的提前降解炭化,使得EP/PBPP复合材料表面形成了致密且坚硬的炭层,其有效地在凝聚相中发挥了屏障作用,使得EP/PBPP复合材料的PHRR和THR相比于纯EP,分别降低了66.9%和50.4%。此外,PBPP在分解过程中产生的含磷自由基有效地在气相中发挥了抑制作用,使EP/PBPP复合材料的av-EHC显著降低,赋予了EP优异的火安全性能。

In order to improve the flame retardant performance of epoxy resin(EP),the flame retardant pentaerythritol aryl phosphonate(PBPP)was successfully prepared by nucleophilic substitution reaction using the traditional char-forming agents pentaerythritol(PER)and phenylphosphonyl dichloride(PPDC)as raw materials.PBPP was introduced into the EP matrix to prepared flame retardant EP composites.The tests show that the EP/PBPP6 composites successfully obtain UL-94 V-0 rating with the limiting oxygen index(LOI)of 32.5%when the mass fraction of PBPP is 6%,and the melting droplets of EP/PBPP are significantly suppressed.Thermogravimetric analysis show that the addition of PBPP promotes the early degradation and charring of the EP matrix and results in the formation of a dense and hard char layer on the surface of EP/PBPP composites,which effectively acts as barrier in condensed phase.Thus,the PHRR and THR of EP/PBPP composites are reduced by 66.9%and 50.4%compared to pure EP.In addition,the phosphorus-containing radicals generated during the decomposition of PBPP effectively exert the inhibiting effect in gas phase,resulting in a significant reduction in the av-EHC of EP/PBPP composites and endowing the EP composites with excellent fire safety properties.