【作者】 赵国璋；

【导师】 施利毅；

【作者基本信息】 上海大学 ， 材料学， 2011， 博士

【摘要】 橡胶基纳米复合材料是以橡胶为连续相,以无机或有机纳米粒子为分散相而制备的复合材料。由于分散相的小尺寸效应、表面效应、量子尺寸效应以及宏观量子隧道效应,橡胶基纳米复合材料在结构、性能及应用方面优于传统的橡胶复合材料,为制备高性能、多功能的复合材料提供了新途径。本论文以高性能橡胶基纳米复合胎面材料、功能材料、密封材料为应用指向,研究了基于纤维状无机纳米填料、层状无机纳米填料、颗粒状无机纳米填料、功能化无机纳米复合填料以及聚合物纳米填料的橡胶基纳米复合材料的制备、结构与性能,主要研究内容及结论主要包括:以纤维状凹凸棒石（AT）为纳米无机填料,分别采用硅烷偶联剂及季铵盐为改性剂对其进行改性,采用机械共混法制备了天然橡胶基凹凸棒石纳米复合材料。研究表明,改性AT与橡胶基体有良好的界面相容性,AT棒晶在橡胶基体中的均匀解离、取向以及良好橡胶/填料界面的形成是实现AT增强效应的关键。同时考察了以四针状氧化锌晶须（T-ZnO_w）及纳米氧化锌（N-ZnO）在胎面材料中协同替代间接法氧化锌（O-ZnO）的效果。研究表明,T-ZnO_w的钉扎效应以及N-ZnO的纳米效应可使二者在协同应用时的效果明显优于O-ZnO。在此基础上,以炭黑（CB）、AT、T-ZnO_w、N-ZnO协同增强橡胶基纳米复合胎面材料。对胎面材料的粒子分散状态、界面结构、填料网络等进行了表征,并对多相纳米填料在橡胶基体中的协同增强机理进行了探讨。研究表明,胎面材料的硫化特性、力学性能、耐老化性能及耐磨耗性能得到明显改善,耐寒性能、耐湿滑性能提高,且滚动阻力和生热降低。以有机改性层状蒙脱土（OMMT）为纳米无机填料,采用机械共混法制备了剥离型及插层型天然橡胶基蒙脱土纳米复合材料。研究表明,OMMT缩短了胶料的硫化时间并增大了其表观交联密度。硫化工艺参数影响OMMT在橡胶基体中的结构演变。OMMT的纳米片层结构对橡胶基体具有明显的增强作用,在较低填量下即可使复合材料的拉伸强度、撕裂强度、定伸应力等力学性能以及动态力学性能得到明显提高,而其阻隔效应也使复合材料的热稳定性及耐溶剂性得到改善。在此基础上,考察了CB与OMMT协同增强橡胶基纳米复合胎面材料的效果。研究表明,CB促进了OMMT在橡胶基体中的插层及分散,而OMMT片层对CB粒子网络具有一定的隔断效应。CB/OMMT粒子杂化网络的形成是实现二者协同增强的关键原因。较低填量的OMMT与CB协同增强时,可使胎面材料获得良好的力学性能、耐老化性能、耐磨耗性能、热稳定性能及耐溶剂性能,并且使胎面材料的耐寒性能和耐湿滑性能提高,但滚动阻力增大,生热增加。以颗粒状纳米重晶石（NB）为无机填料,采用机械共混法制备了天然橡胶基重晶石纳米复合材料。研究表明,双层包覆改性的纳米重晶石（SA-Al₂O₃-NB）与橡胶基体相容性良好且易于分散,可使复合材料获得良好的综合性能。同时,考察了SA-Al₂O₃-NB与CB协同增强橡胶基纳米复合胎面材料的结构及性能。研究表明,SA-Al₂O₃-NB粒子可均匀分散于橡胶基体中,与CB共同组成填料网络,在较低填量下即可使胎面材料的的力学性能、耐老化性能、耐磨耗性能、耐腐蚀性能得到明显提高。动态力学分析表明,SA-Al₂O₃-NB的加入使胎面材料的耐湿滑性能提高,而滚动阻力和生热降低。在实验室材料研究和工艺开发的基础上,进一步组织了百公斤级/批材料中试,制得了性能稳定的高性能橡胶基纳米复合胎面材料及合格的翻新轮胎。以AT作为纳米颗粒合成载体,以液相沉淀法分别在其表面负载纳米氧化铈（CeO₂）及纳米四氧化三铁（Fe₃O₄）,然后采用季铵盐对其进行表面有机化改性,制备了功能化无机纳米复合填料CTAB-AT-CeO₂和CTAB-AT-Fe₃O₄,应用于制备天然橡胶/丁苯橡胶基纳米复合材料。研究表明,CeO₂粒径为5nm左右,负载于AT表面形成芝麻棒状结构。在复合材料制备过程中,CeO₂促进了AT棒晶束的解离和分散,CeO₂的弥散强化使CTAB-AT-CeO₂对橡胶基体的增强作用明显高于CTAB-AT,同时使复合材料的热稳定性及共混性提高。研究表明,Fe₃O₄粒径为10nm左右,负载于AT表面形成具有超顺磁性的功能化纳米复合粉体。CTAB-AT-Fe₃O₄对橡胶基体同样具有良好的增强作用。有机化改性及复合材料制备过程并未改变Fe₃O₄的超顺磁性,因此制备出了兼具优良力学性能和超顺磁性的功能化橡胶基纳米复合材料。以电子束辐照改性的微米级及纳米级的聚四氟乙烯（PTFE）微粉为填料,采用机械共混法制备了三元乙丙橡胶基聚合物纳米复合材料,并对复合材料的硫化特性、界面结合、力学性能、耐磨耗性能、耐压缩永久变形性能以及热降解行为进行了较为系统的研究。研究表明,相对于微米级的PTFE粒子,纳米PTFE粒子极低的表面摩擦系数、高比表面积以及高表面羧基浓度,会对胶料产生润滑效应及延迟硫化效应。同时,纳米级PTFE粒子的纳米效应以及与橡胶基体良好的界面结合使其对橡胶基体具有良好的增强作用,可明显提高复合材料的力学性能。PTFE颗粒的粒径大小、各向同性度以及橡胶/填料界面结合程度是造成复合材料耐压缩永久变形性能差异的主要原因。复合材料的热降解明显分为两个阶段,相对于微米级PTFE粒子,纳米级PTFE粒子促进了橡胶基体的热降解。更多还原

【Abstract】 Rubber nanocomposites are materials that inorganic/organic nanoparticles （dispersed phase） are uniformly dispersed in rubber matrices （continuous phase）. Because of the small size effect, surface effect, quantum size effect and micro-quantum tunnel effect of the nanoparticles, rubber nanocomposites exhibit markedly improved microstructures, properties and applications when compared to traditional rubber composites. Rubber nanocomposites represent a new alternative to prepare high-performance and multifunctional composites. In this paper, fibrillar nanofillers, layered nanofillers, granular nanofillers, inorganic functional composite nanofillers and polymeric nanofillers were employed to prepare rubber nanocomposites which are used in the fields of tire tread, multifunctional materials and sealing materials. The relationships between microstructure and properties of rubber nanocomposites were systematically studied. The main contents and conclusions are as follows:Natural rubber nanocomposites reinforced with fabrillar silicate attapulgite （AT） were prepared by mechanical compounding. Silane coupling agents and quaternary ammonium salts were employed as modifiers to improve the compatibility between AT and the rubber matrix. The results show that the modified AT and natural rubber were compatible. The disaggregation and orientation of AT needles and the strong rubber/filler interfacial interactions are crucial for the reinforcement of AT on the rubber matrix. The application of tetrapod-like zinc oxide whisker （T-ZnO_w） and nano-zinc oxide （N-ZnO） instead of conventional zinc oxide （O-ZnO） in tire tread was investigated. An obvious synergistic effect could be observed when T-ZnO_w and N-ZnO were collaborative applicated due to the anchoring effect of T-ZnO_w and the nanometer effect of N-ZnO. On this basis, carbon black （CB）, AT, T-ZnO_w and N-ZnO were collaborative employed to reinforce the tire tread. Combinding with the investigation of filler dispersion status, rubber/filler interfacial structure and filler network of the nanocomposites, the synergistic reinforcing mechanism of multiphase fillers on the rubber matrix were clarified. The results show that the curing properties, mechanical properties, thermo oxidative resistance, abrasion resistance, cold resistance and wet skid resistance of the nanocomposites were significantly improved. What is more, the rolling resistance and heat build-up of the nanocomposites were reduced.Intercalated/exfoliated natural rubber/organo-montmorillonite （OMMT） nanocomposites were prepared by mechanical compounding. The microstructures and properties of the nanocomposites were investigated and clarified. The results indicate that the introduction of OMMT not only accelerated the curing process but also increased the crosslinking density of the nanocomposites. The microstructure evolvement of OMMT was influenced by the curing process parameters. The mechanical properties, dynamic mechanical properties, thermal stability, oil resistance were dramatically improved by the addition of a small amount of OMMT. Furthermore, CB and OMMT were employed simultaneously to reinforce the tire tread. The results demonstrate that the dispersion and intercalation of OMMT layers were promoted by CB nanoparticles. At the same time, OMMT layers exhibited a partition effect on the CB filler network. The synergistic reinforcement of OMMT and CB in the nanocomposites can be attributed to the formation of CB/OMMT hybrid filler network. Despite possessing higher rolling resistance and heat build-up, the tire tread containing CB and a small amount of OMMT exhibited enhanced mechanical properties, thermo oxidative resistance, abrasion resistance, thermal stability, solvent resistance, cold resistance and wet skid resistance.Natural rubber nanocomposites reinforced with nanobarite （NB） were prepared by mechanical compounding. The results show that the NB modified by sodium aluminate and sodium stearate （SA-Al₂O₃-NB） exhibited outstanding reinforcement due to its homogenous dispersion in the rubber matrix and the strong rubber/filler interactions. Furthermore, the microstructure and properties of the tire tread containing both SA-Al₂O₃-NB and CB were investigated. The results show that SA-Al₂O₃-NB and CB could be uniformly dispersed in the rubber matrix and a special hybrid filler network could be constructed. The mechanical properties, thermo oxidative resistance, abrasion resistance and corrosion resistance were obviously improved. The dynamic mechanical analysis results indicate that the tire tread possesses good wet skid resistance, rolling resistance and heat build-up properties. The pilot scale experiment was carried on based on the laboratory results and hence the high-performance tire tread and retreated tires were obtained.The AT-CeO₂ and AT-Fe₃O₄ composites nanoparticles were prepared by coprecipitation technique in the aqueous suspension of AT. AT-CeO₂ and AT-Fe₃O₄ were fistly modified by hexadecyl trimethyl ammonium bromide （CTAB） and then were used as fillers to prepare natural rubber/styrene butadiene rubber nanocomposites. The results show that the CeO₂ nanoparticles, with a diameter of about 5nm, were absorbed to AT needles’surfaces. CeO₂ nanoparticles enhanced the disaggregation of AT needles during the compounding process. Combinding with the dispersion strengthening of CeO₂, the reinforcement of CTAB-AT-CeO₂ on the rubber matrix was better than that of CTAB-AT. At the same time, the thermal stability and miscibility of the rubber/CTAB-AT-CeO₂ nanocomposites were also improved. The results also show that the as-obtained Fe₃O₄ nanoparticles, with a diameter of about 10nm, exhibits apparent superparamagnetism at room temperature. CTAB-AT-Fe₃O₄ composites nanoparticles also play an obvious reinforcement on the rubber matrix, and hence the multifunctional rubber nanocomposites with both good mechanical properties and superparamagnetism were obtained.Rubber composites based on ethylene propylene diene monomer （EPDM） and electron beam irradiated polytetrafluorethylene （PTFE） micro-/nano- particles were prepared by mechanical compounding. The curing characteristics, morphologies, mechanical properties, abrasion behaviors, permanent compression set and thermal degradation behavior of the composites were investigated. The results show that, in comparison with the PTFE microparticles, the PTFE nanoparticles enhanced the lubrication of EPDM composites and delayed the curing process due to it extremely low friction coefficient, larger specific surface area and higher concentration of carboxyl group on the surfaces. It’s evident that the mechanical properties of EPDM/PTFE nanocomposites were improved due to the nanometer particle dimension and good dispersion of PTFE nanoparticles as well as the efficient interfacial bonding between rubber and PTFE nanoparticles. The particle size, isotropy and the interactions between EPDM and PTFE particles were crucial to the permanent compression set of the EPDM/PTFE nanocomposites. The thermal degradation of the EPDM/PTFE nanocomposites was devided into two stages. However, in comparison with the PTFE microparticles, the PTFE nanoparticles promoted the thermal degradation of EPDM.更多还原