【作者】 汪磊；

【导师】 胡源； 袁国杰； Anna A Stec；

【作者基本信息】 中国科学技术大学 ， 安全科学与工程， 2014， 博士

【摘要】 聚乙烯-醋酸乙烯酯(EVA)是一种常用聚烯烃材料,它可以作为热熔性粘合剂,包装,电线和电缆绝缘,地毯等。但是,其易燃性以及燃烧过程中产生的大量有毒烟气严重制约了聚乙烯-醋酸乙烯酯在相关领域的发展。因此,为了扩大聚乙烯-醋酸乙烯酯材料的使用范围,研究和发展阻燃性聚乙烯-醋酸乙烯酯材料显得非常重要。首先本文综述了无卤阻燃技术应用于聚乙烯-醋酸乙烯酯中的现状。其次,探索了几种含铁氧化物在聚乙烯-醋酸乙烯酯复合材料中阻止燃烧的原因。最后,采用稳态管式炉烟气毒性试验平台(SSTF)研究了这些聚乙烯-醋酸乙烯酯复合材料在氧气充足条件下的燃烧烟气毒性。1.制备出β-羟基氧化铁(p-FeOOH)和二氯代磷酸苯酯修饰的β-羟基氧化铁(p-FeOOPDCP),将其应用于聚乙烯-醋酸乙烯酯中,制备出一系列EVA/β-FeOOH和EVA/β-FeOOPDCP复合材料。热重(TGA)测试表明,复合材料的成炭有明显提高。锥形量热仪测试表明β-FeOOH和β-FeOOPDCP的加入在一定程度上降低热释放速率峰值和总热释放量；热重-红外(TGA-FTIR)测试表明在热解过程中,β-FeOOH或β-FeOOPDCP都降低了基体产生的裂解产物。对燃烧后的炭渣进行X-射线衍射(XRD)测试。与此同时,动态机械热分析(DMTA)测试表明,β-FeOOH和β-FeOOPDCP的加入有效提高了复合材料的玻璃化转变温度(Tg)和在玻璃化转变区域的储能模量。在老化测试中,研究结果表明,β-FeOOPDCP可能对聚合物基体的降解影响不大。2.将β-FeOOH和β-FeOOPDCP作为阻燃协效剂与氢氧化镁复配用于聚乙烯-醋酸乙烯酯材料阻燃,制备出聚乙烯-醋酸乙烯酯/氢氧化镁/β-羟基氧化铁(E VA/Mg(OH)2/β-FeOOH)和聚乙烯-醋酸乙烯酯/氢氧化镁/二氯代磷酸苯酯修饰的β-羟基氧化铁(EVA/Mg(OH)2/β-FeOOPDCP)阻燃复合材料。TGA测试表明,复合材料中β-FeOOH或β-FeOOPDCP能有效地提高复合材料在高温段的热稳定性和成炭量。MCC测试表明,氢氧化镁和β-FeOOH或β-FeOOPDCP复配可以显著降低材料的热释放速率峰值(pHRR),总热释放量(THR)和热释放能力(HRC)。仅将β-FeOOH和β-FeOOPDCP取代1%Mg(OH)2,就能使EVA/Mg(OH)2体系的LOI值由26±0.5vol%分别提高到35±0.5vol%和39±0.5vol%；并且使UL-94值由无级别分别提高到V-2和V-0级别。SEM研究表明,加入β-FeOOPDCP的体系比其它体系炭层更加结实,这可以有效地阻止传热和易燃挥发物的传播,具有很好的阻燃性能。同时,TGA-FTIR测试显示,加入β-FeOOPDCP能有效降低总挥发产物,碳氢化合物,乙酸和CO的生成量。因此,通过引入β-FeOOH或β-FeOOPDCP可以减少火灾隐患。在此基础上,提出了延缓燃烧的原因。3.借鉴β-FeOOH在聚乙烯-醋酸乙烯酯材料的优异表现,将铁酸镧(LaFeO3)应用于聚乙烯-醋酸乙烯酯,制备出聚乙烯-醋酸乙烯酯/氧化铁(Fe2O3),聚乙烯-醋酸乙烯酯/氧化镧(La2O3)和聚乙烯-醋酸乙烯酯/铁酸镧(LaFeO3)复合材料。TGA测试表明LaFeO3的加入使得复合材料在高温阶段的热稳定性与成炭量都有一定的提高；锥形量热测试结果显示,加入LaFeO3可以降低复合材料的热释放速率峰值和总热释放量；炭渣的测试研究表明,LaFeO3可以提高材料的有序炭含量。TGA-FTIR测试揭示在热解过程中,LaFeO3显著降低基体中易燃挥发物的量。并且在老化测试中,结果显示LaFeO3的加入可能也对聚合物基体的降解影响不大。4.把LaFeO3作为阻燃协效剂与膨胀阻燃剂复配,并且制备出聚乙烯-醋酸乙烯酯/膨胀阻燃剂/氧化铁(EVA/APP/PER/Fe2O3),聚乙烯-醋酸乙烯酯/膨胀阻燃剂/氧化镧(EVA/APP/PER/La2O3),聚乙烯-醋酸乙烯酯/膨胀阻燃剂/氧化铁/氧化镧(EVA/APP/PER/Fe2O3/La2O3和聚乙烯-醋酸乙烯酯/膨胀阻燃剂/铁酸镧(EVA/APP/PER/LaFeO3)复合材料。TGA测试表明,Fe2O3, La2O3, Fe2O3与La203混合物和LaFeO3的加入均能提高聚乙烯-醋酸乙烯酯膨胀阻燃复合材料的热稳定性。将Fe2O3,La2O3和LaFeO3取代0.5%膨胀阻燃剂(IFR),就能使EVA/IFR体系的UL-94值由V-2级别都提高到V-0级别。锥形量热测试均表明加入这些氧化物能显著地降低其热释放速率峰值及总热释放量。其中加入LaFeO3的效果最好。SEM研究炭渣的结果显示添加不同氧化物对炭渣形貌有很大影响；采用XPS对炭渣进行元素分析,引入LaFeO3能明显地提高EVA阻燃复合材料的高温稳定性。并且在此基础上,提出了阻燃机理。5.按照相关标准,利用稳态管式炉烟气毒性试验平台(SSTF)研究三组样品(第一组：聚乙烯-醋酸乙烯酯,聚乙烯-醋酸乙烯酯/β-羟基氧化铁,聚乙烯-醋酸乙烯酯/二氯代磷酸苯酯修饰后的-羟基氧化铁和聚乙烯-醋酸乙烯酯/铁酸镧；第二组：聚乙烯-醋酸乙烯酯/氢氧化镁,聚乙烯-醋酸乙烯酯/氢氧化镁/氯代磷酸苯酯修饰的β-羟基氧化铁和聚乙烯-醋酸乙烯酯/氢氧化镁/铁酸镧；第三组：聚乙烯-醋酸乙烯酯/膨胀阻燃剂,聚乙烯-醋酸乙烯酯/膨胀阻燃剂/二氯代磷酸苯酯修饰的-羟基氧化铁和聚乙烯-醋酸乙烯酯/膨胀阻燃剂/铁酸镧复合材料)的烟气毒性。研究表明：在氧气供应充足条件下,聚乙烯-醋酸乙烯酯材料在燃烧过程中,其消耗的氧气主要进入二氧化碳中；β-FeOOPDCP和LaFeO3的加入能够在一定程度上降低复合材料的成烟量和毒性气体。更多还原

【Abstract】 Ethylene-vinyl acetate copolymer (EVA) is a commonly used polyolefin material, which can be used as hot melt adhesives, packaging, wire and cable insulation, carpet and so on. However, its flammability and large amounts of toxic gas and smoke appeared during the combustion process severely restrict the development of ethylene-vinyl acetate copolymer in the relevant fields. In order to expand the application of ethylene-vinyl acetate copolymer, developing flame retardancy ethylene-vinyl acetate copolymer material is very important. Firstly, this paper reviews the feasibility of the application of the flame retardant technology in ethylene-vinyl acetate copolymer. Then the cause of the retarding combustion of several iron oxides in ethylene-vinyl acetate copolymer were studied. Finally, during the burning, toxic gas and smoke from these ethylene-vinyl acetate copolymer composites in the oxygen-rich conditions were discussed by a steady-state tube furnace test platform (SSTF).1. Iron hydroxide (β-FeOOH) and phenyl dichloridophosphate modified iron hydroxide (β-FeOOPDCP) nanoparticles were prepared. Then, they were applied to an ethylene-vinyl acetate copolymer to prepare a series of EVA/β-FeOOH and EVA/β-FeOOPDCP composites. Thermal gravimetric tests showed that char residue from composites was significantly improved. Cone calorimeter tests indicated that the addition of β-FeOOH or P-FeOOPDCP nanoparticle, in some extent, decreased peak heat release rate and total heat release. Thermal gravimetric-Fourier transforms infrared spectrometry (TGA-FTIR) test demonstrated that during the pyrolysis process, the addition of P-FeOOH or β-FeOOPDCP nanoparticle reduced the volatiles form EVA matrix. The residue char after the combustion was conducted by XRD test. At the same time, DMTA tests showed β-FeOOH or β-FeOOPDCP nanoparticle could improve the glass transition temperature (Tg) and the storage modulus of EVA effectively. In the aging test, it was found that5%β-FeOOPDCP might have a very little effect on the photodegradation of EVA matrix.2. β-FeOOH and β-FeOOPDCP nanoparticles were used as co-additives in ethylene-vinyl acetate copolymer/magnesium hydroxide composites to prepare ethylene-vinyl acetate copolymer/magnesium hydroxide/iron hydroxide (EVA/Mg(OH)2/β-FeOOH) and ethylene-vinyl acetate copolymer/magnesium hydroxide/phenyl dichloridophosphate modified iron hydroxide (EVA/Mg(OH)2/β-FeOOPDCP) composites. The results of TGA indicated that β-FeOOH or P-FeOOPDCP in the composite could effectively improve the thermal stability and the amount of residue char at high temperatures. MCC tests showed that magnesium hydroxide with iron hydroxide or phenyl dichloridophosphate modified iron hydroxide could significantly reduce peak heat release rate (pHRR), total heat release (THR) and heat release capacity (HRC) of the composite. Only substituted1%Mg(OH)2, β-FeOOH or β-FeOOPDCP nanoparticle could improve the LOI value of EVA/Mg(OH)2system from26±0.5to35±0.5and39±0.5, respectively; UL-94value increased from V-2to V-0level. SEM studies illustrated that the addition of P-FeOOPDCP nanoparticle system could form more robust char than other systems, which effectively prevented the spread of heat and combustible volatiles to improve the flame retardancy. Meanwhile, TGA-FTIR test demonstrated that the addition of β-FeOOPDCP nanoparticle could reduce the amount of total volatile products, hydrocarbons, acetic acid and CO. Thus, the introduction of β-FeOOH or P-FeOOPDCP nanoparticle could reduce fire hazards. Based on these, the reason for retarding the combustion was proposed.3. Learning from the outstanding performance of phenyl dichloridophosphate modified iron hydroxide (β-FeOOPDCP) nanoparticles in ethylene-vinyl acetate copolymer, lanthanum ferrite (LaFeO3) nanoparticle was applied in ethylene-vinyl acetate copolymer and ethylene-vinyl acetate copolymer/iron oxide (FeaO3), ethylene-vinyl acetate copolymer/lanthanum oxide (La2O3) and ethylene-vinyl acetate copolymer/lanthanum ferrite (LaFeO3) composites were prepared. TGA tests showed that the adding of LaFeO3nanoparticle improved thermal stability and amount of the residue char at high temperatures; The results from microscale combustion calorimeter (MCC) testing indicated that LaFeO3nanoparticle could reduce the peak heat release rate (pHRR), heat release capacity (HRC) and total heat release (THR) values of ethylene-vinyl acetate copolymer (EVA); The tests about the residue char illustrated the addition of LaFeO3nanoparticle raised the amount of ordered carbon of the material. TGA-FTIR test indicated that during the pyrolysis process, LaFeO3significantly reduced the amount of flammable volatiles generated from EVA matrix. In the aging test, the results showed that5%LaFeO3might also have a very little effect on the photodegradation of EVA matrix.4. LaFeO3nanoparticle was used as a co-additive in ethylene-vinyl acetate copolymer/intumescent flame retardant (EVA/APP/PER) composite. Then ethylene-vinyl acetate copolymer/intumescent flame retardant/iron oxide (EVA/APP/PER/Fe2O3), ethylene-vinyl acetate copolymer/intumescent flame retardant/lanthanum oxide (EVA/APP/PER/La2O3) and ethylene-vinyl acetate copolymer/intumescent flame retardant/iron oxide/lanthanum oxide (EVA/APP/PER/Fe2O3/La2O3) composites were also prepared. TGA tests showed the addition of Fe2O3, La2O3, the mixture (Fe2O3and La2O3) and LaFeO3improved the thermal stability of ethylene-vinyl acetate copolymer/intumescent flame retardant (EVA/APP/PER) composite. Only replaced0.5%intumescent flame retardant (APP/PER), Fe2O3, La2O3, the mixture (Fe2O3and La2O3) and LaFeO3all could raise the UL-94value of EVA/IFR system from V-2to V-0level. Cone calorimeter tests demonstrated that adding these oxides could effectively reduce the peak heat release rate (pHRR) and total heat release (THR). LaFeO3had the best effect. The char residue was measured by SEM, indicating that the addition of different oxides had great impacts on the morphology of char residue; Elements from char residue were analyzed by XPS. The results indicated that the addition of LaFeO3could significantly improve the thermal stability of EVA retardant composites at high temperatures. Based on these, this flame retardant mechanism was proposed.5. According to international standards, a steady-state tube furnace test platform (SSTF) was used to study toxic gas and smoke from three groups of samples, including the first group:EVA, EVA/β-FeOOH, EVA/β-FeOO PDCP and EVA/LaFeO3; the second group:EVA, EVA/Mg(OH)2, EVA/Mg(OH)2/β-FeOOPDCP and EVA/Mg(OH)2/LaFeO3; the third group:EVA, EVA/APP/PER, EVA/APP/PER/β-FeOOPDCP and EVA/APP/PER/LaFeO3composites. The study showed that under the oxygen-rich condition, in the thermal or combustion process of ethylene-vinyl acetate copolymer, the consumption of oxygen mainly came into carbon dioxide; β-FeOOPDCP and LaFeO3could, to a certain extent, reduce the amount of toxic gas and smoke of the composites.更多还原