【作者】 李曦；

【导师】 王文魁； 战再吉；

【作者基本信息】 燕山大学 ， 亚稳材料制备技术与科学， 2012， 博士

【摘要】 环氧树脂纳米复合材料以其质轻、化学稳定以及较好的力学、热学和阻隔等性能在航空航天、航海潜水、国防军事等领域显示了良好的应用前景。但是已有此类材料一般只含有一种维度的纳米材料，尽管提高了材料的某些性能，却往往伴随着其它性能的下降。目前，这种提高了某些性能却要下降其它性能的难题仍无法解决，限制了其广泛应用。本论文提出了将不同维度的纳米材料同时复合的思路，试图解决这一难题，经过实验和理论探讨，达到了预期的目的。制备出了单一维度纳米材料增强的纳米复合材料——环氧树脂/零维纳米SiO₂纳米复合材料和环氧树脂/二维蒙脱土纳米复合材料，两种维度纳米材料增强的纳米复合材料——环氧树脂/零维纳米SiO₂/二维蒙脱土纳米复合材料。运用热重分析、差式扫描量热分析、力学性能测试、X射线衍射分析、扫描电子显微分析、透射电子显微分析等实验手段研究了其性能与结构，探讨了相应的机理。研究结果表明：与纯环氧树脂相比，零维纳米SiO₂增强的环氧树脂/零维纳米SiO₂纳米复合材料的力学性能有170%的提高，但热力学稳定性却有下降。与纯环氧树脂相比，二维蒙脱土增强的环氧树脂/二维蒙脱土纳米复合材料的热分解温度、弯曲性能和冲击性能分别有12.3℃、14%和21%的提高，但玻璃化转变温度和拉伸强度却有0.9℃和25%的下降。与纯环氧树脂相比，零维纳米SiO₂和二维蒙脱土增强的环氧树脂/零维纳米SiO₂/二维蒙脱土纳米复合材料的热力学稳定性和力学性能均得到了极大的提高，其中热分解温度和拉伸模量分别有17.3℃和248%的增长。与单一维度纳米材料增强的环氧树脂/零维纳米SiO₂纳米复合材料和环氧树脂/二维蒙脱土纳米复合材料相比，不同维度纳米材料增强的环氧树脂/零维纳米SiO₂/二维蒙脱土纳米复合材料，无论是热力学稳定性还是力学性能均有着全面和大幅度的提高。三种环氧树脂纳米复合材料性能的变化，源于其微观结构存在着的显著差异。在环氧树脂/零维纳米SiO₂纳米复合材料中，零维纳米SiO₂在环氧树脂基质中分布不均匀，存在富集区。在环氧树脂/二维蒙脱土纳米复合材料中，二维蒙脱土保持着明显的层状结构，形成的是典型的插层型纳米复合材料。在环氧树脂/零维纳米SiO₂/二维蒙脱土纳米复合材料中，零维纳米SiO₂分布均匀；蒙脱土的层状结构已不存在，被离析为单个的纳米薄片；两者交错散布于环氧树脂基体中，组成了一种新的结构。对不同维度纳米材料大幅度提高材料全面性能的原因和相应微观结构的变化进行了探究。通过理论计算和推导，阐明了这种性能的提高是由其独特的微观结构形成的，表明这种独特的微观结构是通过不同维度的纳米材料间的不同作用力而产生的。以上工作说明：选择适宜的不同维度的纳米材料复合于环氧树脂中，是制备新型综合性高性能环氧树脂纳米复合材料的成功思路。这也为今后开发新型综合性高性能纳米复合材料提供了新的途径。更多还原

【Abstract】 The rapid development of aerospace, submarine, and weaponry industries raises anurgent need for lightweight materials with good comprehensive performance. Epoxynanocomposites hold great promise for meeting this need. They not only retain such epoxymerits as light total weight and high chemical resistance, but also obtain impressivelyenhanced mechanical, thermal, and barrier properties due to the incorporation ofnanoparticles. However, most epoxy nanocomposites now available only containnanoparticles of the same dimensionality. Although these nanocomposites can improve insome properties, the improvement is frequently accompanied by decrease in some otherproperties. So far, this compromise is still a problem that defies solution. In this study, anew strategy was presented to solve this problem that multiple dimensionally differentnanoparticles were co-incorporated into epoxy matrix. Through experimental andtheoretical exploration, the intended purpose was achieved.In this study, nanocomposites reinforced by nanoparticles of single dimensionalitywere prepared by separately incorporating zero-dimensional nanoSiO₂andtwo-dimensional montmorillonite （MMT） into epoxy resin, termedepoxy/zero-dimensional nanoSiO₂nanocomposite and epoxy resin/two-dimensional MMTnanocomposite, respectively. Nanocomposites reinforced by nanoparticles of two differentdimensionalities were prepared by co-incorporating zero-dimensional nanoSiO₂andtwo-dimensional MMT into epoxy resin, termed epoxy/zero-dimensionalnanoSiO₂/two-dimensional MMT nanocomposite. Thermogravimetric analysis （TGA）,differential scanning calorimetry （DSC）, mechanical property tests, X-ray diffraction（XRD）, scanning electronic microscopy （SEM）, and transmission electronic microscopy（TEM） were used to study the properties and structures of the nanocomposites, as well asexplore their enhancing mechanism. The results are as follows:The zero-dimensional nanoSiO₂reinforced epoxy/zero-dimensional nanoSiO₂nanocomposites exhibited enhancement in mechanical properties but decrease in thermalstability, when compared with pure epoxy.The two-dimensional MMT reinforced epoxy/two-dimensional MMTnanocomposites displayed improved thermal decomposition temperature, flexuralperformance, and impact performance, but showed declined glass transition temperatureand tensile strength in comparison with pure epoxy.As to the epoxy/zero-dimensional nanoSiO₂/two-dimensional MMT nanocomposites,co-reinforced by zero-dimensional nanoSiO₂and two-dimensional MMT, they obtainedgreatly improved thermal stability and mechanical properties compared with pure epoxy. Both thermal stability and mechanical properties of the epoxy/zero-dimensionalnanoSiO₂/two-dimensional MMT nanocomposites, which are reinforced by multipledimensionally different nanoparticles, were comprehensively and considerably higher thanthose of the epoxy/zero-dimensional nanoSiO₂nanocomposites andepoxy/two-dimensional MMT nanocomposites, which are reinforced by dimensionallysingle nanoparticles.Corresponding to the above performance variations, the three kinds of epoxynanocomposites showed significant differences in microstructure. In theepoxy/zero-dimensional nanoSiO₂nanocomposites, zero-dimensional nanoSiO₂particleswere unevenly distributed in the matrix, with some enriching regions present. In theepoxy/two-dimensional MMT nanocomposites, the two-dimensional MMT retainedlayered structure, forming typical intercalated nanocomposites. In theepoxy/zero-dimensional nanoSiO₂/two-dimensional MMT nanocomposites, thezero-dimensional nanoSiO₂particles were evenly distributed, and the MMT lost itslayered structure and was disassembled into individual nano-plateletts. Thezero-dimensional nanoSiO₂particles and the MMT nano-plateletts dispersed in the epoxymatrix in an interlacing manner and formed a new structure.The reasons for the considerable and comprehensive improvement in materialperformance, generated by co-reinforcement with nanoparticles of multiple dimensionalies,were investigated; the corresponding changes in material microstructure were alsoexplored. Through theoretical calculation, it was elucidated that the performanceimprovement is due to the distinctive microstructure of the epoxy/zero-dimensionalnanoSiO₂/two-dimensional MMT nanocomposites, and that this distinctive microstructureis derived from the interaction between the dimensionally different nanoparticles.The experimental and theoretical calculation results indicate that co-incorporation ofproper, dimensionally different nanoparticles into epoxy matrix is a successful way toprepare new comprehensive and high performance epoxy nanocomposites. Furthermore,this study provides a new path to comprehensive and high performance nanocompositedevelopment in the future.更多还原