熔体插层聚合物/粘土纳米复合材料

对国内外熔体插层法制备聚合物／粘土纳米复合材料(PCN)的研究进展进行了综述。介绍了影响PCN结构形态的各种因素；对熔体插层法制备PCN的热力学、动力学研究进行了总结；详细讨论了熔体插层的机理研究及理论模型。并对熔体插层法制备PCN提出了展望。     

聚酰亚胺/蒙脱土纳米复合材料

利用插层法合成的聚酰亚胺／蒙脱土纳米复合材料相比于纯聚酰亚胺有更好的力学性能、热稳定性、气体阻隔性及更低的介电性、吸湿性和热膨胀性。是一种性能优异、具有广泛应用前途的新型有机、无机－纳米复合材料。这是因为粘土在聚酰亚胺基体中以纳米尺度均匀分散并与基体形成了强的化学结合。本文重点综述了该复合材料的制备、结构表征及性能等方面的研究，并展望该材料的应用前景。     

动态扭振法观察环氧树脂/蒙脱土插层聚合物的二次固化

聚合物 /无机纳米复合材料是当今材料研究中的热点。但由于无机纳米颗粒在聚合物中不易分散 ,有时用具有纳米层间距的片晶结构的无机矿物 ,如蒙脱土作填料 ,通过聚合时的热效应来撑开片晶达到蒙脱土的纳米级分散 ,制得所谓的插层聚合物〔1〕。插层型纳米复合材料不仅物理力学性能有很大提高 ,并且也为高分子凝聚态物理工作者提供了研究聚合物分子在二维空间受限情况的理想模型。由于在蒙脱土层间和层外的聚合物所处的环境不一样 ,它们的一些行为会有所不同。本文在用动态扭振法研究环氧树脂 /蒙脱土插层聚合物的等温固化行为时 ,观察到了该…     

混合条件对环氧有机土纳米复合材料插层剥离行为及性能的影响

采用X 射线衍射仪、透射电镜 (TEM )研究了混合条件 ,即混合温度和时间 ,对环氧 /16 烷基胺有机蒙脱土体系在固化前的混合物以及加入固化剂、促进剂固化后有机土的插层与剥离行为的影响 .同时采用拉伸试验机、冲击试验机和热机械分析仪测定了插层与剥离型纳米复合材料的物理力学性能 .从X 射线衍射看出 ,有机土很容易在混合过程被环氧所插层 .混合物经固化后可以形成插层型或剥离型纳米复合材料 .存在一个混合温度 时间 插层剥离转变的 3 T图 .只有在一定的混合条件的区域内才能形成剥离型纳米复合材料 .剥离型比插层型纳米复合材料具有较高的力学性能     

插层法悬浮聚合制PMMA/蒙脱土纳米复合材料

文献中蒙脱土的有机化处理一般采用一次插层法处理 ,本文采用了一种新的二次插层法 ,通过对一次插层法和二次插层法插层效果的比较 ,确定了二次插层法为一种理想的蒙脱土有机化方法 .经过MMA对蒙脱土插层的悬浮聚合 ,FT IR ,XRD和SEM等试验结果证明蒙脱土已经被有效地撑开 ,但发现蒙脱土的加入会降低聚合反应的转化率和聚合物的收率 ,悬浮聚合物颗粒的形态变得不规则 ,粒径也变大 .差热分析、溶解实验和应力 应变测试均表明蒙脱土的加入能提高PMMA的性能 ,蒙脱土的最佳用量在 3 %左右 .     

胶乳接枝插层法天然橡胶/蒙脱土/聚丙烯酸丁酯纳米复合材料结构与性能的研究

采用胶乳接枝插层法,引入单体,制备了天然橡胶蒙脱土聚丙烯酸丁酯纳米复合材料.X射线衍射(XRD)和透射电镜(TEM)结果表明,在单体丙烯酸丁酯(BA)的作用下,改性蒙脱土片层被进一步撑大,并在橡胶基体中以纳米级分散;动态粘弹谱(DMA)测定结果显示,该体系的玻璃化温度有所提高,且60℃时具有较低的tanδ值,说明具有较小的滚动阻力;物理机械性能测试表明该方法有效地实现了对天然橡胶的补强.     

聚乳酸/蒙脱土纳米复合材料的结构和热性能

聚乳酸/蒙脱土纳米复合材料的结构和热性能;聚乳酸;蒙脱土;纳米复合材料;插层     

插层聚合聚丙烯-蒙脱土纳米复合材料的微观结构形态

使用偏光显微镜，扫描电镜，透射电镜和广角X射线衍射法研究了插层聚合法制备的聚丙烯－蒙脱土（PP－MMT）纳米复合材料的微观结构和形态发展。结果表明，随着插层聚合反应的进行，较大的初级MMT粒子逐渐剥离成较小的次级粒子。次级粒子由2－20片的单个MMT片层组成，其层间充满了PP分子链。提出了插层聚合过程中PP－MMT复合材料的形态发展模型。另外，MMT的加入对PP的球晶形态也有重要影响，PP完整的球晶随MMT的加入逐渐变小和趋于扭曲甚至破坏。     

插层聚合制备聚丙烯/蒙脱土纳米复合材料及其结构性能表征

将插层聚合的概念引入烯烃聚合,制备了聚丙烯／蒙脱土（PP／MMT）纳米复合材料。X射线衍射和TEM分析结果表明,蒙脱土在聚丙烯基体中达到了纳米级的分散,动态力学性能研究结果表明,在高于Tg的温度区域内PP／MMT纳米复合材料的储能模量（E′）成倍增加,加入8％的蒙脱土（MMT）,PP／MMT的E′提高近3倍。PP／MMT的玻璃化转变温度Tg有一定程度的提高,随蒙脱土含量的增加,PP／MMT的热分解温度和热变形温度（HDT）都有大幅度提高。     

环氧树脂/层状无机物纳米复合材料

概述了近年来国内外环氧树脂／层状无机物纳米复合材料的研究现状，详细介绍厂环氧树脂／蒙脱土、环氧树脂／水滑石及环氧树脂／石墨三种代表性环氧树脂纳米复合材料的制备、性能及研究进展。     

Intercalated clay nanocomposites: Morphology,mechanics, and fracture behavior

Intercalated nanocomposites of modified montmorillonite clays in a glassy epoxy were prepared by crosslinking with commercially available aliphatic diamine curing agents. These materials are shown to have improved Young's modulus but corresponding reductions in ultimate strength and strain to failure. The results were consistent with most particulate‐filled systems. The macroscopic compressive behavior was unchanged, although the failure mechanisms in compression varied from the unmodified samples. The fracture toughness of these materials was investigated and improvements in toughness values of 100% over unmodified resin were demonstrated. The fracture‐surface topology was examined using scanning electron and tapping‐mode atomic force microscopies and shown to be related to the clay morphology of the system. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1137–1146, 2001     

Development of Composite Adsorbents of Carbon and Intercalated Clay for N2and O2Adsorption: A Preliminary Study

Composite adsorbents of carbon and alumina intercalated montmorillonite were prepared and characterized by adsorption of N₂and O₂at various temperatures. The effects of pyrolysis, temperature, heating rate, subsequent degassing, and doping of cations and anions were investigated. The adsorption capacities of the composite adsorbents developed at higher temperatures (0 and −79°C) are found to be larger than those of normal alumina pillared clays. The experimental results showed that the framework of these adsorbents is made of alumina particles and clay sheets while the pyrolyzed carbon distributes in the space of interlayers and interpillars. The pores between the carbon particles, clay sheets, and alumina pillars are very narrow with very strong adsorption forces, leading to enhanced adsorption capacities at 0 and −79°C. The composite adsorbents exhibit features similar to those of carbonaceous adsorbents. Their pore structures, adsorption capacities, and selectivities to oxygen can be tailored by a controlled degassing procedure. Meanwhile, ions can be doped into the adsorbents to modify their adsorption properties, as usually observed for oxide adsorbents like zeolite and pillared clays. Such flexibility in pore structure tailoring is a potential advantage of the composite adsorbents developed for their adsorption and separation applications.     

Thermal Properties of E-beam Cured Epoxy/Thermoplastic Matrices for Advanced Composite Materials

The aim of this work is to investigate the possibility to improve the thermal behaviour of epoxy based systems, cured by ionizing radiation, in order to produce matrices for advanced carbon fibres composites. Blends of two epoxy monomers, difunctional and trifunctional, have been polymerized by e-beam irradiation and the dynamic mechanical thermal properties have been investigated. The increase of the concentration of the trifunctional epoxy monomer in the blend causes a marked increase of the Tg, but strongly decreases the reactivity. Subsequently, blends of the same epoxy monomers with a high Tg thermoplastic toughening agent have been considered and their reactivity and the thermal properties of the obtained materials have been also studied. The experimental results show that the thermoplastic component increases the reactivity of the difunctional/trifunctional blends, without a significant decrease of the glass transition temperature which still satisfies the requirements for advanced composite materials.     

以功能为导向的插层结构功能材料结构设计及应用

插层结构功能材料是近年来迅速发展的一类新型功能材料。北京化工大学化工资源有效利用国家重点实验室多年来以插层结构功能材料的研究为基础,针对＂以功能为导向的结构设计＂等关键科学问题展开了大量基础和应用研究,实现了对材料微观主客体的设计和介观、宏观结构的调控,制备了多种新型插层结构功能材料,广泛应用于催化、环保、医药、纺织、...     

Effect of Surface-modified Clay on the Thermal Stability and Insulation of Polyorganosiloxane Foam

Polyorganosiloxane foam(SIF) nanocomposites reinforced with vinyl-modified montmorillonite(Mt-V) and hydrox-yl-modified montmorillonite(Mt-OH) were prepared through cross-linking and foaming. The effects of modified Mt on the density, pore morphology, and thermal and compressive properties of the prepared polyorganosiloxane foams were investi-gated. The structure of the polyorganosiloxane foam was studied by solid-state nuclear magnetic resonance analysis. Clay dispersion in polyorganosiloxane nanocomposites and pore morphology were investigated by X-ray diffraction and scan-ning electron microscopy analyses. The thermal and mechanical properties of the prepared materials were also evaluated by differential scanning calorimeter, thermogravimetric analysis, thermal diffusivity and compressive strength. The results show that Mt-V exhibits improved cell structure, thermal insulation, and crush compressive than Mt-OH. The addition of modified Mt reduces the density, cell size, and thermal conductivity but increases the high-temperature resistance and com-pressive strength of the nanocomposite. The amount of the residues of SIF/Mt-OH nanocomposites increases by 9% com-pared with that of the pure SIF. Furthermore, SIF/Mt-V decreases the thermal conductivity to 0.014 W/mK and the cell size to 98 μm. Those properties give the material potential application value in the aerospace and construction industry.     

Ethylene-Octene Copolymer-Nanosilica Nanocomposites: Effects of Epoxy Resin Functionalized Nanosilica on Morphology,Mechanical, Dynamic Mechanical and Thermal Properties

A comparative study of the structural, thermal, mechanical and thermomechanical properties of ethylene-octene copolymer 1

1 Ethylene-octene copolymer is produced using Dow's INSITETM ™ constrained geometry catalyst and process technology. ENGAGE the trade name of this copolymer.

(mPE) 2

2 This copolymer will be represented as mPE .

nanocomposites synthesized with pure nanosilica (NS) and nanosilica-functionalized with diglycidyl ether of bisphenol-A (ENS) has been reported. These nanocomposites were prepared using “melt mixing” method at a constant loading level of 2.5 wt. %. The effects of pure nanosilica (NS) and epoxy resin-functionalized-nanosilica (ENS) on the above mentioned properties of ethylene-octene copolymer were analyzed by wide-angle-x-ray diffractometer (WAXD), transmission electron microscope (TEM), thermo gravimetric analyzer (TGA), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM). TEM studies have shown a better dispersion of nanoparticles in case of ethylene-octene copolymer-epoxy resin-functionalized-nanosilica nanocomposite (mPE-ENS) than that of ethylene-octene copolymer-nanosilica nanocomposite (mPE-NS). The tensile tests show that organic modification of nanosilica particles brings up an appreciable increase in yield strength, ultimate tensile strength and elongation at break of the polymer. DMA studies have shown an increase in the storage modulus and glass transition temperature for mPE-ENS with respect to mPE-NS. Further, the TGA results have shown a higher thermal stability for mPE-ENS in comparison to mPE-NS.     

纳米sio2/聚丙烯酸酯复合涂层的热降解

纳米sio2;聚丙烯酸酯;复合涂层;热降解     

二氧化硅／环氧树脂复合涂层的制备及其疏水性能

采用喷涂技术,在马口铁表面喷涂环氧树脂和二氧化硅复合涂层,研究了二氧化硅的含量对表面疏水性的影响,复合涂层的疏水性随二氧化硅含量的增加而增加．当二氧化硅质量分数增大到40％时,所制备的复合涂层与水的接触角约为141°且具有较小的滚动角．     

稀土复合弹性材料的制备和力学性能

利用稀土醇盐与季铵盐化的吡啶改性丁苯橡胶乳液反应,制备含稀土ＰＳＢＲ胶片,然后与天然橡胶并用,获得含稀土复合材料弹性材料发现其物理力学性能有明显提高。通过红外光谱、差示扫描热量计以及交联密度分析,讨论了其结构与性能的关系。