聚合物纳米复合材料韧性和破坏行为

在总结高分子材料增韧机理、高分子纳米复合材料冲击破坏行为的基础上,探讨了高分子纳米复合材料的增韧机理。纳米无机粒子起应力集中的作用导致界面脱黏、空化与基体屈服是其增韧高分子材料的主要原因,而碳纳米管则起桥联裂纹、偏转裂纹方向、传递界面应力使聚合物基体屈服而增韧高分子材料。对聚合物／层状填料纳米复合材料而言,分散在聚合物基体中的插层或剥离的无机纳米片层对复合材料银纹的形成有抑制作用,其二维几何结构不利于片层周围基体的屈服与界面脱黏、空化,因而不能增韧高分子材料,反而还导致了聚合物／层状填料纳米复合材料抗冲击强度的降低。高分子材料的纳米复合目前很难达到橡胶增韧的效果,若同时采用纳米复合技术与官能化弹性体增韧技术,可望设计、制备出一系列高强度、高韧性的高分子纳米复合材料。     

天然橡胶／有机粘土纳米复合材料的制备与表征

自从丰田中心率先研究出了尼龙6／有机粘土纳米复合材料之后，聚合物／层状硅酸盐纳米复合材料引起了很多高分子科学家的关注。纳米复合材料就是一些无机填料以纳米级均匀分散在高聚物基体中形成的复合材料。粘土片层被聚合物插层或剥离可形成聚合物／粘土纳米复合材料。     

无机纳米复合高分子材料的制备

无机纳米复合高分子材料是由无机纳米材料和有机高分子复合而成，着重介绍了溶胶-凝胶（Sol-Gd）法、插层复合法、共混法和原位聚合法等主要制备方法。     

有机改性与乳液插层法相结合制备的丁苯橡胶/黏土纳米复合材料的结构与性能

针对现有的乳液插层法所制备的橡胶／黏土纳米复合材料中填料与橡胶之间界面结合较弱的缺点,在乳液插层法中对无机黏土进行有机改性,制备出力学性能优异的纳米复合材料。X射线衍射和透射电子显微镜技术分析表明,有机改性后的复合材料中黏土被部分地有机改性,且在基体中以纳米尺寸分散。     

有机改性与乳液插层法相结合制备的丁苯橡胶/黏纳米复合材料的结构与性能(英文)

针对现有的乳液插层法所制备的橡胶/黏土纳米复合材料中填料与橡胶之间界面结合较弱的缺点,在乳液插层法中对无机黏土进行有机改性,制备出力学性能优异的纳米复合材料。X射线衍射和透射电子显微镜技术分析表明,有机改性后的复合材料中黏土被部分地有机改性,且在基体中以纳米尺寸分散。     

用于高分子材料改性领域的无机纳米填料化学改性方法

综述了对高分子材料中广泛使用的无机纳米填料进行表面化学改性的方法,包括偶联剂改性法、酯化改性法等小分子改性剂法,以及表面原位接枝聚合改性等大分子接枝法。这些方法不仅解决了无机纳米填料易团聚、分散性差及与高分子材料复合相容性不佳的问题,而且有效地提升了其在电子、催化、能源、生物医学等领域的应用性能。同时介绍了各种方法的改性机理、适用条件和优缺点,并对改性方法的工艺优化和发展研究方向进行了展望。     

“有机包覆三元共混体系”新型材料的研究

以超细无机填料如碳酸钙为核，表面包覆上一层有机高分子材料如某种橡胶形成一种刚性粒子－硬核／橡胶－软壳特定结构的粒子来增强增韧高分子材料既是塑料改性的最新进展又可使复合材料性能大大提高，本文阐述有关技术进展和有关模型有建立以及填料和母料的研制。     

蒙脱土增强EVM橡胶纳米复合材料的研究

通过FTIR、XRD、TEM、TG、CONE等不同试验手段,对蒙脱土增强EVM橡胶复合材料的结构、耐热、阻燃等性能进行了较为系统的研究。结果表明：经插层剂处理的Na-MMT,硅酸盐的层间距大幅度提高;大部分的org-MMT实现了在EVM橡胶复合材料的纳米插层、脱层分散;蒙脱土纳米复合材料的耐热性能比其他填料优异得多;同时材料的阻燃性能提高明显。     

磁性纳米高分子复合材料发展现状

磁性纳米高分子复合材料是以高聚物为基体与磁性纳米材料复合而成的一类材料,其常用的制备方法有原位生成法,溶胶-凝胶法,插层法等。综述了磁性纳米高分子复合材料的制备方法及性能,并对磁性纳米高分子复合材料的进一步发展进行了展望。     

无机材料对超薄型钢结构防火涂料性能的影响

介绍了晶须、石墨插层化合物、硅微粉、纳米二氧化硅、二氧化钛、硼酸锌等无机材料对超薄型钢结构防火涂料的防火性能、涂膜质量等理化性能的影响,指出以合适的无机新材料在适当的用量下对传统防火涂料进行必要的改性,是进一步提高超薄型钢结构防火涂料各项性能的有效方法。     

Study of morphology,mechanical properties,and thermal behavior of green aliphatic–aromatic copolyester/bamboo flour composites

Aiming at development of completely biodegradable composite materials based on locally available low‐cost bamboo flour (BF) as filler, structure properties correlations in aliphatic–aromatic copolyester/BF composites fabricated by melt mixing have been studied by means of different techniques such as electron microscopy, X‐ray diffraction, tensile testing, and thermogravimetric analysis (TGA). It has been demonstrated that the BF can be successfully incorporated homogeneously into the biodegradable polymeric matrix up to high content. The filler weakly adheres to the matrix as demonstrated by the pulling up of bamboo fibers on the electron micrographs and further attested by TGA. At high filler concentration, the polymer acts merely as binding material. The semicrystalline framework of the matrix polymer is hindered by the presence of the fibers, the structural changes being more pronounced at the surfaces than in the bulk, which indicates preferential segregation of the fibers toward the specimen surface. This opens new possibilities for a more detailed engineering of materials surfaces. The mechanical properties of the composites are suited for low‐load‐bearing applications. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Active-Filler-Controlled Pyrolysis of Preceramic Polymers

Manufacturing of bulk ceramic components from materials in the system Si-Me-C-N-O (Me = Ti, Cr, V, Mo, Si, B, CrSi₂, MoSi₂, etc.) from preceramic organosilicon polymers - such as poly(carbosilanes), poly(silazanes), or poly(siloxanes) - has become possible by incorporating reactive filler particles into the liquid or solid polymer pre-cursor. During pyrolytic decomposition of the polymer matrix, the filler particles react with carbon from the polymer precursor or nitrogen from the reaction gas atmosphere to form new (oxy)carbide or (oxy)nitride phases embedded in a nanocrystalline Si-O-C(-N) matrix. The selective expansion encountered in the filler phase reaction can be used to compensate for the polymer shrinkage upon pyrolytic conversion. The formation of a transient pore net-work between 400° and 1000°C is governed by the polymer decomposition as well as the filler particle reaction kinetics. Thus, the properties of the oxycarbonitride composite materials can be tailored by controlling the microstructures of the polymer-derived matrix phase, the filler network, and the residual porosity. Near-net-shape forming of bulk ceramic components, even with complex geometry, is possible, making novel applications of polymer-derived bulk materials in biomedical, electrical, and mechanical fields highly interesting.     

A novel method to prepare high-resistivity polymer composites

A novel method was developed for the preparation of high-resistivity conductive polymer composites reproducibly. The conventional method which involves the simple mixing of a conductive filler and a polymer usually produces a conductive polymer composite having a loading curve with a region in which the resistivity changes rapidly as the filler concentration changes. Hence, it is very difficult to obtain reproducible materials in that region. This newly developed method involves the preparation of a conventional conductive polymer composite, which is prepared by the simple mixing of carbon black and a polymer as the first step. The resulting compound, which is crosslinked by either electron-beam radiation or a chemical-crosslinking agent, is ground into a fine powder (composite filler) with the particle size less than 250 microns. The composite filler is mixed with another polymer to form a conductive particulate composite which has a loading curve showing a more gradual change of resistivity as a function of filler concentration. The modification of the loading curve is controlled by the resistivity, the shape, and the size of the composite filler.     

Polymer and nanobelt derived nanomaterials: opening doors to revolutionary stadia

ABSTRACT

The state-of-the-art article presents concepts of nanobelt nanofiller, inimitable properties of derived polymeric nanocomposite, applications, and outlook on challenges to gain next generation high-performance materials. Nanobelt is a one-dimensional nanostructured nanomaterial. Owing to minuscule size and high surface area, nanobelt possesses unique structural, optical, electronic, mechanical, and thermal characteristics. Nanobelt exists in various forms such as carbon nanobelt, polymer nanobelt, and inorganic. These nanobelts have been used to develop polymer/nanobelt nanocomposites. Homogeneous dispersion of nanobelt in polymer matrices is desirable to enhance the characteristics of polymer/nanobelt nanocomposite. Consequently, innovations in design, fabrication, and properties of various polymer/nanobelt nanocomposite are summarized. Applications of polymer/nanobelt nanocomposite are reviewed for Li-ion battery, supercapacitor, sensor, membrane, and biomedical arenas.     

高分子梯度材料的研究

对填料／聚合物、聚合物／聚合物和单一聚合物等类型的高分子梯度材料的研究进行了综述。讨论了探索制备高分子梯度材料的途径以及表征方法。     

Protonenleitende Komposit‐Membranen für zukunftsorientierte Anwendungen in Brennstoffzellen,Entsalzungsanlagen und in der Photokatalyse

Inorganic filler materials are often incorporated into polymer membranes to improve their mechanical, thermal and chemical stabilities. In case of proton‐conducting polymers, however, it is necessary to support or at least not to disturb the proton‐conducting matrix. By suitable combination of polymer and filler, effective and highly conductive composite membranes can be prepared. This article gives an overview of the possible applications of a special kind of such proton‐conducting composite membranes containing functionalized SiO₂ particles with ordered mesoporosity in fuel cell, in desalination and in photocatalysis.     

Thermoset/graphene polymer composites—A review of processing and properties

Polymer-carbon nanocomposites incorporate the exceptional properties of both the polymer matrices, such as low cost and simple processing, with the distinctive features of the carbon-based fillers, such as high electrical and thermal conductivities, and excellent mechanical properties. Various fillers like carbon black (CB), graphite, expanded graphite (EG), and carbon nanotubes (CNTs) are being used to produce materials with advanced properties. However, at high filler loading, these filler materials have some major challenges such as filler agglomeration. Recently, graphene has gained increased interest as an alternative filler to produce polymer nanocomposites with advanced characteristics. Thermosetting polymer composites with graphene fillers are being considered for multiple applications and are a subject of interest for researchers because of enhanced properties like excellent corrosion resistance and low density. This review outlines studies to improve the mechanical, electrical, and thermal properties of thermoset/graphene composites.     

Linear viscoelasticity of polymer melts filled with nano-sized fillers

The linear dynamic rheology of polymer melts filled with nano-sized fillers is investigated in relation to a proposed two phase model. A common principle is disclosed for nanofilled polymers exhibiting either fluid- or solid-like behaviors with increasing filler volume fraction. The bulky polymer phase far away from the filler inclusions in the nanocomposites behaves the same as in the unfilled case while its contribution to the composite modulus is enlarged due to strain amplification effect. The filler forms aggregates together with polymer chains absorbed on the filler surface, which is termed as the “filler phase” in the proposed model. The dynamics of the “filler phase” slow down with increasing filler concentration. The applicability of the proposed two phase model is discussed in relation to the well-known structural inhomogeneity of nanofilled polymers as well as the strain amplification and the filler clustering effects.     

高分子材料微观形态结构的扫描电镜研究

利用扫描电镜对聚乙烯(PE)、丙烯腈-丁二烯-苯乙烯共聚物(ABS)等高分子材料填料的分散性及表面与断裂界面进行了研究。结果表明,扫描电镜能够详细观察研究高分子材料的表面结构、微观相分离等,便于表征高分子材料微观结构形态,是分析高分子材料微观结构形态的有效手段。