【作者】 张天龙；

【导师】 崔益华；

【作者基本信息】 南京航空航天大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 环氧树脂具有良好的电绝缘性以及优异的耐腐蚀性等优点,因而被广泛应用于汽车、航空航天、建筑和微电子等诸多领域。然而,未经阻燃改性的环氧树脂属于易燃材料,在使用过程中存在着火灾安全隐患。DOPO衍生物因其无卤低毒的优点,近年来常被用于阻燃环氧树脂,但只含有磷这一种阻燃元素的DOPO衍生物阻燃效率较低,需要引入其他阻燃元素,通过协同阻燃作用以提高其阻燃效率。因此,本文以DOPO为阻燃中间体,合成了一种含磷氮双阻燃元素的反应型阻燃剂,将其用于环氧树脂的阻燃改性。同时,为了进一步解决DOPO类阻燃剂有毒烟气释放量大的问题,引入了金属有机骨架材料(MOFs),获得了含P、N双元素的改性MOFs,并制备了阻燃环氧树脂,对其阻燃性能、热性能和力学性能进行了研究。主要的研究内容及结果如下:(1)以DOPO和2-氨基苯并咪唑为原料,通过经典的Atherton-Todd反应,合成了同时含有P、N双阻燃元素的反应型阻燃剂:6-((1氢-苯并咪唑-2-基)氨基)二苯并[1,2]氧膦6-氧化物(BADO),并确定了其最佳合成工艺。采用红外光谱分析和核磁共振分析对BADO的结构进行了表征。元素分析结果表明,产物BADO中P、N元素的含量分别达到了8.85%和11.94%。(2)将阻燃剂BADO加入到环氧树脂中,制备了BADO阻燃环氧树脂。实验结果表明,随着BADO含量的增加,环氧树脂的阻燃性能大幅度提升。当BADO的含量为7.5wt%时,LOI和UL-94分别达到了29.7%和V-0,同时热释放速率的峰值(pk-HRR)和总热释放量(THR)与纯环氧树脂相比分别降低了32.3%和17.4%。通过残炭的微观形貌以及热重红外联用分析探究了阻燃机理。BADO在气相和凝聚相能够同时发挥阻燃作用,而且BADO中的P、N元素存在协同阻燃效应,阻燃效果得到进一步的提高。(3)采用BADO作为有机配体对ZIF-8进行改性,制备了含P、N双阻燃元素的改性金属有机骨架材料(BADO@MOFs)。通过XRD和XPS对BADO@MOFs的晶体结构和元素组成进行表征,采用SEM以及EDS对BADO@MOFs的微观形貌进行了研究。TGA分析结果表明,BADO@MOFs在750℃时的残炭率高达41.9%。(4)以BADO@MOFs为阻燃剂,制备了BADO@MOFs阻燃环氧树脂。实验结果显示,仅5wt%的BADO@MOFs添加量便能使环氧树脂的LOI从原先的19.8%提升至28.4%,UL-94达到V-0级,pk-HRR、THR和烟释放量(TSP)相较于纯环氧树脂分别降低了32.9%、15.2%和50.1%,CO的最大释放速率从18.4mg/s降低至11.7mg/s。因此,BADO@MOFs阻燃环氧树脂具有良好的阻燃和抑烟性能。TGA分析结果显示,EP/BADO@MOFs5在750℃时的残炭率为23.1%,说明BADO@MOFs在环氧树脂燃烧过程中具有良好的催化成炭能力。通过对BADO@MOFs阻燃环氧树脂燃烧后炭层的微观形貌进行分析可知,BADO@MOFs可以促进环氧树脂燃烧过程中多孔骨架状炭层的形成,能够有效阻止氧气的进入,抑制燃烧的进行,并降低有毒烟气的释放,起到凝聚相阻燃的效果。更多还原

【Abstract】 Epoxy resins are widely used in automotive,aerospace,architecture and microelectronics due to their excellent electrical insulation and corrosion resistance.However,epoxy resins without flame retardant modification are flammable materials,and there are fire safety hazards in the process of use.DOPO derivatives have been used to flame retardant epoxy resins in recent years because of their halogen-free and low toxicity,but DOPO derivatives containing only phosphorus have low flame retardant efficiency,so it is necessary to introduce other flame retardant elements to improve their flame retardant efficiency through synergistic flame retardant effect.Therefore,in this paper,DOPO was used as flame retardant intermediate to synthesize a reactive flame retardant containing phosphorus and nitrogen,which was used in the flame retardant modification of epoxy resin.At the same time,in order to further solve the problem of large toxic smoke emission of DOPO flame retardants,metal-organic framework materials(MOFs)were introduced.Modified MOFs containing P and N were obtained,and the flame retardant epoxy resin was prepared,and its flame retardant,thermal and mechanical properties were studied.The main research contents and results are as follows:(1)Using DOPO and 2-aminobenzimidazole as raw materials,a reactive flame retardant containing both P and N flame retardant elements: 6-((1-hydrogen-benzimidazole-2-yl)amino)dibenzo [1,2]phosphine oxy 6-oxide(BADO)was synthesized by classical Atherton Todd reaction,and the optimum synthesis process was determined.The structure of BADO was characterized by IR and NMR.The results of elemental analysis showed that the contents of P and N in BADO reached 8.85%and 11.94% respectively.(2)The flame retardant epoxy resin of BADO was prepared,using BADO as flame retardant.The experimental results showed that the flame retardancy of epoxy resin was greatly improved with the increase of BADO content.When the content of BADO was 7.5wt%,LOI and UL-94 reached 29.7%and V-0 respectively,and the peak heat release rate(pk-HRR)and total heat release(THR)decreased by 32.3% and 17.4% respectively compared with pure epoxy resin.The mechanism of flame retardancy was studied through the microstructure of carbon residue and thermogravimetric infrared analysis.BADO could play a flame retardant role in both gas phase and condensed phase,and the synergistic flame retardant effect of P and N elements in BADO further improved the flame retardant effect.(3)The modified metal-organic framework(BADO@MOFs)containing P and N double flame retardant elements was prepared by using BADO as the organic ligand to modify ZIF-8.The crystal structure and elemental composition of BADO@MOFs were characterized by XRD and XPS,and the microstructure of BADO@MOFs was studied by SEM and EDS.TGA analysis results showed that the carbon residue rate of BADO@MOFs was 41.9% at 750℃.(4)The flame retardant epoxy resin of BADO@MOFs was prepared,using BADO@MOFs as flame retardant.The experimental results showed that the LOI of epoxy resin increased from 19.8% to28.4%,UL-94 reached V-0 grade,pk-HRR,THR and TSP decreased by 32.9%,15.2% and 50.1%,respectively,compared with pure epoxy resin,with only 5wt% BADO@MOFs addition.The maximum release rate of CO was reduced from 18.4mg/s to 11.7mg/s.Therefore,the flame retardant epoxy resin of BADO@MOFs had good flame retardant and smoke suppression properties.The results of TGA analysis showed that the carbon residue rate of EP/BADO@MOFs5 was 23.1% at750℃,indicating that BADO@MOFs had good catalytic capacity for carbon formation in the combustion process of epoxy resin.Through the analysis of the microstructure of the carbon layer after the combustion of BADO@MOFs flame retardant epoxy resin,it could be seen that BADO@MOFs could promote the formation of porous skeleton carbon layer in the combustion process of epoxy resin,effectively prevented the entry of oxygen,inhibited the combustion process,and reduced the release of toxic smoke,and played a coalesce phase flame retardant effect.更多还原