新型含氮阻燃剂/PEPA协同阻燃PP的性能

摘要

以三聚氯氰、对羟基苯甲酸甲酯、水合肼为原料经两步反应合成了一种新型含氮阻燃剂4,4',4"-(1,3,5-三嗪-2,4,6-三取代)三氧三苯甲酰肼(TNTN),并通过核磁共振等对其进行表征.将合成的含氮阻燃剂TNTN与1-氧-4-羟甲基-2,6,7-三氧杂-1-磷杂双环[2.2.2]辛烷(PEPA)以不同配比制备膨胀型阻燃聚丙烯(PP)材料(IFR-PP).通过极限氧指数(LOI)、垂直燃烧(UL-94)、热重(TG)分析、锥形量热(CCT)法以及扫描电子显微镜(SEM)对阻燃PP燃烧及热稳定性能进行表征.结果表明,IFR-PP同时具有良好的阻燃性及抗熔滴能力,当PEPA∶TNTN=2∶1时,UL-94达到V-0级,LOI值达到了33.7％,表现出良好的阻燃性能.TG测试表明:阻燃剂的加入使IFR-PP材料提前降解,同时提高了材料的成炭性能,当PEPA∶TNTN=5∶1时,600℃时IFR-PP材料的残炭量由空白样的0.07％提高到了20.6％.CCT测试表明:相对于纯PP,经阻燃剂改性后的PP热释放率和总热释放量均显著减少.SEM测试表明:不同配比阻燃剂的加入使PP在燃烧过程中形成膨胀、致密的炭层,很好地保护了下层材料,提高了PP材料的阻燃性能.%A novel nitrogen containing flame retardant,4,4',4"-(1,3,5-triazine-2,4,6-triyl)tris(oxy) tribenzohydrazide (TNTN) was synthesized from cyanuric chloride,methyl-4-hydroxybenzoate,hydrazine hydrate.The structure of TNTN was characterized by 1H NMR,13C NMR spectrum analysis.The synthesized compound and 2,6,7-trioxa-l-phosphabicyelo-[2.2.2] octane-4-methanol-1-oxide(PEPA) was incorporated into polypropylene (PP) with different ratio to prepare intumescent flame retardant polypropylene thermosets (IFR-PP).The combustion and thermal properties of PP thermosets were investigated by limiting oxygen index (LOI),vertical burning (UL-94),thermogravimetric (TG) analysis,cone calorimetry (CCT) and scanning electron microscopy (SEM) tests.The results demonstrate that IFR-PP has both excellent flame retardancy and anti-dripping ability.When the ratio of PEPA and TNTN is 2 ∶ 1,PP thermosets pass UL-94 V-0 flammability rating and its LOI value reach 33.7％,which shows a good flame retardant performance.TG test results reveal that the incorporation of IFR-PP into PP stimulate the degradation of thermosets ahead of time and charring formation,when the ratio of PEPA and TNTN is 5 ∶ 1,char yield of thermosets increase from 0.07％ to 20.6％ at 600℃.CCT parameter show that heat release rate and total heat release is also obviously reduced compared to pure PR The incorporation of TNTN and PEPA promote PP thermosets forming more homogeneous and compact char layer during combustion by SEM tests,which prevente the underlying matrix from further decomposition and combustion,consequently enhancing the flame retardancy of PP thermosets.