【作者】 白志满；

【导师】 胡源； 袁国杰；

【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】 不饱和聚酯(Unsaturated Polyester Resin, UPR)具有优异的机械性能、电性能和耐化学腐蚀性能等优点,UPR是增强复合材料领域中使用量最大的一种热固性树脂。然而,UPR的易燃性限制其广泛的应用。为此,需要对不饱和聚酯进行阻燃处理。随着人们对环境污染问题认识的深入,国际相关环保法规日益严格,UPR阻燃研究向环境友好的趋势发展。本论文在综述了阻燃不饱和聚酯最新研究进展的基础上,针对阻燃不饱和聚酯研究的局限和缺点,通过分子设计,合成含磷、氮、硅等阻燃元素的无卤阻燃单体和阻燃剂,通过“反应型”和“添加型”的方法将其引入至不饱和聚酯基体中；进一步研究将反应型的阻燃单体作为UPR稀释交联剂取代苯乙烯,并结合纳米复合技术,制备本质阻燃UPR及其纳米复合材料；研究阻燃单体及阻燃剂对UPR热稳定性、燃烧性能及阻燃性能等性能的影响,探讨无卤阻燃UPR的阻燃机理,主要的研究工作如下：1.通过分子设计,分别合成含磷、氮阻燃剂TRIPOD-DOPO和含磷、硅阻燃剂DOPO-VTS;并通过FTIR、1HNMR,31PNMR、MS等分析手段对合成的阻燃剂分子结构进行表征。TRIPOD-DOPO通过物理共混法直接添加到UPR中,制备阻燃UPR/TRIPOD-DOPO样品；DOPO-VTS通过溶胶-凝胶法添加到UPR中,制备含磷的UPR/SiO2有机无机杂化材料。通过TGA、MCC、LOI研究阻燃UPR的热稳性、燃烧性能和阻燃性能,结果表明：阻燃剂的加入,提高了UPR在高温区间内的热稳性和热氧化稳定性,且具有较高的残炭量,氧气能够促进TRIPOD-DOPO催化成炭性能；随着阻燃剂添加量的增加,阻燃UPR的LOI值增加且热释放速率峰值和总热释放量显著降低。此外,TG-IR结果表明：两类基于DOPO结构的阻燃剂不仅通过提高残炭量发挥凝聚相阻燃作用,而且通过捕捉H/OH活性自由基,抑制燃烧链式反应发挥气相阻燃作用。2.合成两种含丙烯酸双键的反应型阻燃单体ODOPB-AC和APBPE,通过自由基共聚的方法,将两种反应型单体引入至UPR分子链中,制备本质阻燃UPR。热重结果表明：反应型阻燃单体的引入降低了材料的起始热分解温度,ODOPB-AC的刚性分子结构抵消了部分起始热分解温度的降低,但是材料在高温阶段的热稳定性和热氧化稳定性得到提高,氧气能够促进ODOPB-AC的催化成炭性能。MCC和LOI结果表明：阻燃单体的引入能够降低材料的热释放速率峰值和总热释放量,提高材料的LOI值。ODOPB-AC和APBPE能够促进UPR高温热解成炭,阻止热量和质量在基体和燃烧区域间的传递,提高材料的阻燃性能。此外,APBPE主要在凝聚相发挥阻燃作用,而ODOPB-AC既能够在气相也能够在凝聚相发挥阻燃作用。3.合成了马来酰亚胺结构的反应型含磷阻燃剂SPDPC-HPM,通过自由基共聚反应,引入至UPR分子结构中,制备本质阻燃的UPR材料。SPDPC-HPM的引入,起始热分解温度和热稳定性得到提高,克服了传统有机磷阻燃剂降低材料的起始热分解温度的缺点；动态热力学分析结果表明：在SPDPC-HPM添加量为1wt%时,材料的储能模量得到提高,且阻燃的UPR仅有一个内耗峰,说明SPDPC-HPM与基体共聚性能良好；此外,MCC结果显示阻燃样品的热释放速率峰值和总热释放量均得到了降低；SPDPC-HPM添加量为10wt%时,可以使得UPR的氧指数达到26.0vol%; SPDPC-HPM的加入促进UPR高温热解成炭,形成的炭层结构更加致密,内部呈蜂窝状的结构,能够有效地隔绝热量和质量在基体和燃烧区域传递,保护基体。4.分别通过熔融法和溶液法制备UPR预聚体与层状无机物(OMMT和S-LDH)的预插层混合物,通过自由基原位聚合法,制备了UPR/层状无机物纳米复合材料。XRD和TEM结果表明：S-LDH在UPR基体中能够得到插层和插层-剥离的结构,分散性较好；此外,与熔融预插层法相比,溶液预插层法所制备的纳米复合材料具有较好的分散效果。层状无机物的引入提高了UPR的热稳定性和残炭量,并降低了UPR最大热失重速率,纳米复合材料具有更低的pHRR和THR。通过对比研究发现,溶液预插层法制备的UPR/S-LDH具有最好的分散效果,最高的热稳定性、最低的pHRR和THR。5.为了进一步提高UPR的阻燃性能,将APBPE和TAIC (1:1w/w)混合阻燃剂作为稀释交联剂取代UPR体系中的30wt%的苯乙烯,同时引入S-LDH,制备本质阻燃UPR及其纳米复合材料。XRD和TEM结果表明：S-LDH在阻燃UPR基体中高度分散,显示出剥离结构；TGA结果表明：阻燃单体APBPE的柔性分子结构和较弱化学键P-O-C造成UPR的起始热分解温度降低,S-LDH的引入,能够提高初始阶段UPR的热稳定性：阻燃单体及层状无机物的引入提高了UPR高温阶段的热稳定性,阻燃单体主要在凝聚相发挥阻燃作用,形成保护性的炭层；本质阻燃UPR/S-LDH纳米复合具有最低pHRR和THR,显示出优异的阻燃性能。更多还原

【Abstract】 Typical unsaturated polyester resin (UPR) has excellent mechanical properties, electrical properties, chemical corrosion resistance and etc., is one of the largest amount of thermosetting resin used for reinforced composites. However, both very poor resistances to fire and high smoke densities associated during burning limit its application in some areas. Therefore, it is necessary to improve the flame retardancy of UPR. As the increasing pressure from rigorous legislation and environmental pollution problem, the research and development of flame retardant UPR switch to environmental friendly trend.Aiming at overcoming the limitations and shortcomings of the present study of flame retardant UPR, a series of phosphorus-, nitrogen-and silicon-containing novel compounds were synthesized and well characterized including additive and reactive types of flame retardants by the method of the molecular design, on the basis of the latest research progress on the halogen-free flame retardant polymers. The synthesized additive and reactive flame retardants were incorporated into UPR by physical blending and copolymerization methods, respectively. Furthermore, the reactive flame retardant monomers were used as both diluting and crosslinking agent to substitute30wt%styrene in UPR, combining with layered inorganic compounds such as montmorillonite (MMT) and Zn-Al layered double hydroxide (ZnAl-LDH), to prepare inherent flame retardant UPR and nanocomposites. The thermal degradation and flammability behaviors of UPR composites were investigated, and the flame retardant mechanism was clarified. The main research works of this dissertation were illustrated as follows:1. Two Kinds of additive flame retardants, including phosphorus-, nitrogen containing compound named TRIPOD-DOPO and phosphorus-, silicon-containing compound named DOPO-VTS were synthesized and well characterized using FTIR,1H NMR,31P NMR and mass. TRIPOD-DOPO was directly introduced into the UPR by the physical blending, and DOPO-VTS was introduced into the UPR matrix by Sol-Gel method to prepare a novel phosphorus-containing flame retardant UPR/SiO2hybrid materials. The thermal stability and flammability of samples were evaluated by TGA and MCC. TGA results showed that TRIPOD-DOPO and DOPO-VTS can contribute improved thermal and thermo-oxidative stability at high temperature region, as well as higher char yields to UPR matrix. Meanwhile much lower values of pHRR and THR were observed for the composites from MCC results with an increased LOI value, demonstrating a significant improvement in the flame retardancy to UPR. The TG-IR indicated that both TRIPOD-DOPO and DOPO-VTS acted in the gas phase through flame inhibition and in the condensed phase through formation of protective residual char.2. Based on the molecular design, two kinds of novel phosphorus containing reactive monomers named10-(2,5-diacrylicester phenyl)-9,10-dihydro-9-oxa-10-pho-sphaphenanthrene-10-oxide (ODOPB-AC) and acryloxyethyl phenoxy caged bicyclic phosphate ester (APBPE) were synthesized and copolymerized with unsaturated chemical bonds in UPR and styrene with different concentration to prepare flame retardant UPR. The TGA results revealed that the introduction of APBPE decreased the initial decomposition temperature, but UPR/ODOPB-AC composites showed slight reduction of initial decomposition temperature due to the rigid molecular structure of ODOPB-AC. However, both the APBPE and ODOPB-AC improved the thermal and thermo-oxidative stability at higher temperature region with the decreased MMLR as well as higher char yields. Most significant is the difference between air and nitrogen atmosphere observed for the residual char of UPR/ODOPB-AC composites, indicating that the presence of oxygen has a dramatic effect on the char formation. Moreover, the results demonstrated that both ODOPB-AC and APBPE could increase the LOI value and reduce the pHRR and THR values. This is believed to be attributed to that ODOPB-AC and APBPE catalyzed the degradation of UP to form the protective char layer based on the condensed phase flame retardant mechanism, which inhibited the heat and mass transfer between UPR matrix and gas phase, delayed the degradation of UPR, and thus improved the flame retardancy of UPR. Besides, ODOPB-AC also acted in the gas phase through flame inhibition based on the gas phase flame retardant mechanism.3. A phosphorus containing bismaleimide named SPDPC-HPM was synthesized and incorporated into backbone of UPR via polymerization. The introduction of SPDPC-HPM improved thermal stability of composites and promoted the formation of residual char. The initial thermal decomposition temperature was also increased due to the rigid maleimide group, which overcome the shortcoming of decreased initial thermal stability caused by phosphorus-containing flame retardant. Moreover, the flame retardant composites showed the reduced pHRR and THR due to the higher char yields and lower MMLR compared with the pure UPR. Furthermore, the composites exhibited higher LOI value, indicating the better flame retardancy because of protective residual char through the condensed phase mechanism, which can shield the underlying polymeric substrate from further burning.4. UPR/layered inorganic compounds nanocomposites with different layered inorganic compounds (OMMT and S-LDH) were successfully prepared by pre-intercalates of UPR pre-polymer into layered inorganic compounds followed by in situ polymerization. XRD and TEM results showed that the intercalated or intercalative-exfoliated structures were observed in UPR/S-LDH nanocomposites, but UPR was slightly intercalated by OMMT. The S-LDH dispersed better than OMMT in UPR matrix. Meanwhile the nanocomposites pre-intercalated by solution blending method also show better dispersion of layered inorganic compounds than melting blending method. The UPR/layered inorganic compounds nanocomposites possessed higher thermal stability with lower MMLR, and greater char yields at the higher temperature region from the TGA results. Among the nanocomposites, UPR/LDH-s showed the highest thermal stability and greatest char yields, as well as the lowest pHRR.5. In order to further improve the flame retardance of UPR, the flame retardant mixture of APBPE and TAIC (1:1w/w) was used to substitute30wt%of the styrene in the UPR as both diluting and crosslinking agent. Meanwhile the S-LDH was also introduced into the UPR to prepare the inherent flame retardant UPR nanocomposites. The nanocomposite exhibited almost exfoliated structure from XRD and TEM results. The incorporation of flame retardants decreased the thermal stability at the low temperature region due to the flexible molecular structure and weak P-O-C bond of APBPE, which can be improved by addition of S-LDH. The thermal stability was enhanced at the high temperature with the higher char yields, indicating that the flame retardants mainly acted in the condensed phase via char formation. The MCC results exhibited that the flame retardant nanocomposite possessed the lowest pHRR and THR, indicating that the formulation of APBPE/TAIC//S-LDH contributed the most effective flame retardance to the UPR.更多还原