Yuan Gaowei, Yang Bing, Chen Yinghong, Jia Yinggang
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University Chengdu 610065 China
College of Science, Northeastern University Shenyang 110819 China.
RSC Adv. 2018 Oct 25;8(63):36286-36297. doi: 10.1039/c8ra07418f. eCollection 2018 Oct 22.
Due to the poor dispersion in polymer matrix, graphene can hardly be used alone as a flame-retardant additive for polymers. In this paper, a novel halogen-free flame retardant - the ternary graft product of silsesquioxane, graphene oxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (PMGO) with a structure of graphene oxide layers modified with the synergistic flame retardant multiple elements of phosphorous, nitrogen and silicon was synthesized and then used in combination with traditional intumescent flame retardant (IFR) to enhance the flame retardancy of polypropylene (PP). The experimental results show that the thermal and flame retardant properties of flame-retardant (FR) PP composites are significantly improved by introducing 5 wt% PMGO as well as 20 wt% IFR. The peak heat release rate and total heat release of the FR PP composite are reduced 61.5% and 40.2%, respectively, compared to neat PP. Based on the char layer observation and thermal analysis, the enhancement in flame retardancy is mainly attributed to the outstanding intumescent char layers with high strength and thermal stability formed under the synergistic effect of PMGO and IFR. Besides, the introduced phosphorous, nitrogen and silicon hydrophilic groups do not show the negative effects on the surface hydrophobicity of flame retardant PP materials, which could broaden its scope of application.
由于石墨烯在聚合物基体中的分散性较差，它很难单独用作聚合物的阻燃添加剂。本文合成了一种新型无卤阻燃剂——倍半硅氧烷、氧化石墨烯与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物的三元接枝产物（PMGO），其结构为氧化石墨烯层被磷、氮、硅协同阻燃多元素修饰，然后将其与传统膨胀型阻燃剂（IFR）复配使用，以提高聚丙烯（PP）的阻燃性能。实验结果表明，引入5 wt%的PMGO以及20 wt%的IFR能显著提高阻燃聚丙烯（FR-PP）复合材料的热性能和阻燃性能。与纯PP相比，FR-PP复合材料的峰值热释放速率和总热释放量分别降低了61.5%和40.2%。基于残炭层观察和热分析，阻燃性能的提高主要归因于在PMGO和IFR的协同作用下形成了高强度和热稳定性的优异膨胀型残炭层。此外，引入的磷、氮和硅亲水性基团对阻燃PP材料的表面疏水性没有负面影响，这可以拓宽其应用范围。
