复合材料界面研究现状（上）

本文综述了复合材料界面研究现状,着重介绍了界面控制、界面表征及界面微观力学研究的国外最新进展.     

什么是界面？

界面是指两相接触的约几个分子厚度的过渡区，若其中一相为气体，这种界面通常称为表面。严格讲表面应是液体和固体与其饱和蒸气之间的界面，但习惯上把液体或固体与空气的界面称为液体或固体的表面。常见的界面有：气-液界面，气-固界面，液-液界面，液-固界面，固-固界面。     

界面腐蚀、界面理论及界面性能表征

本文首先分析了界面腐蚀期况,综述了复合材料的各种界面理论,提出了作者的见解,最后系统介绍了界面性能表征的各种方法。     

驱油用聚丙烯酰胺溶液界面特性研究

使用 TRACKR全自动液滴界面张力仪测量了不同试验条件下十二烷 /聚丙烯酰胺溶液界面扩大、缩小时的流变特征及界面张力 ,开发出了用以表征液膜强度的界面黏弹性 E的测量方法。在十二烷 /聚丙烯酰胺界面形成稳定的过程中界面 (扩张 )黏弹模量不断增加 ,并逐渐达到恒定 ,其中弹性成分所占比例远大于黏性成分即 E′>E″。考察的聚合物浓度范围为 5 0～ 2 0 0 0 mg/ L ,界面黏弹模量从 1 7.6提高到 3 0 .6m N·m-1。放置 3 d后的聚合物溶液界面黏弹模量保留率为 82 .8%。实验结果表明聚合物浓度变化对界面张力影响不显著。     

复合材料界面研究现状（下）

本文综述了复合材料界面研究现状，着重介绍了界面控制、界面表征及界面微观力学研究的国内外最新进展．     

复合材料界面研究现状 中

本文综述了复合材料界面研究现状，着重介绍了界面控制、界面表征及界面微观力学研究的国内外最新进展。     

大坝混凝土的水泥石-石英集料界面结构研究

本文用扫描电镜、X射线能谱分析仪和透射电镜对丰满大坝混凝土的水泥石-石英集料界面区进行分析观察,提出了将该界面区分为与界面平行的三层界面结构模型。对所提出的界面结构模型进行了讨论,并指出Ca(OH)_2晶体簇与钙矾石晶体在其层间未相互穿插生长,有可能是界面区的薄弱环节。     

界面性质对气液传质的影响

界面性质对气液传质有重要影响。分子通过界面时需克服界面自由能，界面两侧的浓度不一致。本文导出了两者之间的关系     

碳纤维／锂铝硅（LAS）玻璃陶瓷的界面结构及界面反应

用TEM,EDAXJ SAD,XPS,SEM等手段,分别对两种成分的锂铝硅(LAS)系统玻璃陶瓷(LAS_I和LAS(?))为基材在不同热压时间下获得的具有不同强度和韧性的碳纤维补强复合材料的界面及从复合材料萃取出来的纤维表面进行了研究。短时同热压的碳纤维-LAS_I界面层窄,界面较致密,而长时同热压,界面层变宽且疏松。碳纤维-LAS(?)存在较宽的气体扩散层界面,界面区还含有由界面反应生成的NbC颗粒,较长时间的热压,界面层变窄,NbC颗粒沉积在纤维上,改善了界面结构。界面反应和界面结构的形成及其对复合材料性能的影响进行了分析和讨论。     

流体间界面热力学研究的进展

界面热力学是化学工程中一个重要的分支,它与流体相平衡、流体与流体间传质分离过程等密切相关。本文着重介绍界面分子热力学、两种流体相间界面张力的估算及表面张力在流体界面上吸附等热力学研究的状况,并预测了未来的发展前景。     

聚合物表面的润湿性及其应用

本文论述了真实聚合物表面的润湿性，聚合物表面张力的计算，界面张力的极性理论及酸碱理论，并对近年来材料表面的改性在聚合物中的应用进行了简要的评述。     

Polyphenyletherketone and polyphenylethersulfone adhesives for metal-to-metal joints

Two major factors play an important part in improving adhesive bonding in crystalline polyphenyletherketone ( ) and amorphous polyphenylethersulfone ( ) polymer-to-metal joint systems: (1) the mechanical strength of reaction product layers formed at polymer/metal interfaces is greater than that of the polymer itself; and (2) the extent of mechanically weak Fe₂O₃ layers on interfacial metal surfaces, which should be minimized to avoid the undesirable cohesive failure mode through these layers. As a result, the most promising failure mechanism for good bond performance was the mixed cohesive failure modes in which separation occurred in both the polymer and adhesive layers at the polymer/metal interfaces.     

X-ray Photoelectron Study of Chemical Interactions at Ti/Polymer Interfaces

We have used X-ray photoelectron spectroscopy to study the chemical interactions at the interface formed during in situ deposition of Ti atoms on epoxy, triazine, and polystyrene surfaces. We find that for deposition on thick polymer films (1-2 mm) the primary component at the interface is TiO₂ with small amounts of titanium nitride and titanium carbide. The source of the oxygen in the TiO₂ is water or molecular oxygen dissolved in the polymer films. We also find that the Ti/triazine interface is more stable to heat treatment than the Ti/epoxy interface. This result is attributed to the higher glass transition temperature of triazine. For thin triazine films (～ 100Å) we observe that titanium carbide is the dominant product, with smaller amounts of oxide and nitride. Aging in air causes the carbide and nitride to convert to the more thermodynamically-stable oxide. Titanium carbide is also the primary initial species at the Ti/polystyrene interface.     

A Spectroscopic Technique for Studies of Water Transport Along the Interface and Hydrolytic Stability of Polymer/Substrate Systems

Information on water transport along the polymer/substrate interface is valuable for understanding the mechanisms and the controlling factors affecting the water-induced adhesion loss of polymer-coated metals, adhesive-bonded joints, and polymer/fiber composites subjected to aqueous environments. This paper presents data to demonstrate the capability of a technique, which combines a vertical cell with Fourier transform infrared spectroscopy in the multiple internal reflection mode, for studying water transport along the polymer/substrate interface and interfacial hydrolytic stability of polymeric composites and systems exposed to water and high relative humidities. The technique can distinguish water transport through the film from that along the interface; the latter transport is predominant for polymer/untreated substrate systems. Spectroscopic analyses of fractured surfaces of poor and well-bonded polymer/substrate systems after water exposure indicate that the technique is capable of discerning a hydrolytically-stable interface from a water-susceptible interface.     

Correlation between physical bonding and mechanical properties of wood–plastic composites: part 2: effect of thermodynamic factors on interfacial bonding at wood–polymer interface

Abstract

The main objective of this study was to find out if there is any significant correlation between physical properties and interfacial bonding of interphases in wood–plastic composites. To this end, high-density polyethylene (HDPE), mixture of 3% maleic anhydride grafted polyethylene (MAPE) and HDPE (coded as MHDPE) and polylactic acid (PLA) were separately interacted with veneers to identify factors underlying interfaces. Plastics were first melted at 180?°C and dispensed on wood surfaces so that the contact angle (CA) could be directly measured. Wood sanding moderately decreased the CAs of plastics in order of PLA, MHDPE, and HDPE. The treatment of veneers with MAPE comprehensively improved wetting, as the CA of HDPE was significantly reduced on the wood surface after the treatment. Thereafter, the interfacial shear strengths (IFSS) of the wood–polymer interface were determined using the automated bonding evaluation system. PLA had the highest IFSS both for unsanded and sanded veneers. Comparing both parts of this research finally revealed that applying sanding or/and MAPE treatments resulted in lower surface free energy and higher IFSS at the wood–polymer interface. However, our observations support the idea that, at higher temperatures, wetting of composites is mainly influenced by polymer properties rather than interfacial tension at the wood–polymer interface.     

Thermal Properties of Graphene Filled Polymer Composite Thermal Interface Materials

Recent years have witnessed a staggering escalation in the power density of modern electronic devices. Because increasingly high power density accumulates heat, efficient heat removal has become a critical limitation for the performance, reliability, and further development of modern electronic devices. Thermal interface materials (TIMs) are widely employed between the two solid contact surfaces of heat sources and heat sinks to increase heat removal for electric devices. Composites of graphene and matrix materials are expected to be the most promising TIMs because of the remarkable thermal conductivity of graphene. Here, the recent research on the thermal properties of graphene filled polymer composite TIMs is reviewed. First, the composition of graphene filled polymer composite TIMs is introduced. Then, the synthetic methods for graphene filled polymer composite TIMs are primarily described. This study focuses on introducing the methods for improving and characterizing the thermal properties of graphene filled polymer composite TIMs. Furthermore, the challenges facing graphene filled poly­mer composite TIMs for thermal management applications in the modern electronic industry and the further progress required in this field are discussed.

     

Characterisation of buried glass/cyclo-olefin polymer film interfaces by sum-frequency generation vibrational spectroscopy

Plasma gas-modified cyclo-olefin polymer (COP) surfaces and the interfaces between borosilicate glass and COP films were investigated by sum-frequency generation (SFG) vibrational spectroscopy. Upon exposure to oxygen gas plasma, the SFG signal intensities increased, indicating an improvement in the orientational order at the surface functional groups. In addition, thermal annealing following lamination improved the COP interphase molecular ordering and increased the number density of functional molecules at the interfaces.     

Improved adhesion of aluminum layers deposited on plasma and thermally treated poly(paraphenylene-vinylene) films substrates

Searching for better adhesion properties of metallic thin films to polymer substrates, we have studied the influence of the plasma and thermal treatments of poly(paraphenylene-vinylene) thin films on their adhesion to aluminum layers. The adhesion was found to be substantially increased when the polymer surface was treated with oxygen by RF sputtering, or when it was kept at high temperature prior to the metal deposition. An attempt has been made to explain the adhesion improvement in terms of surface analysis (XPS) and scanning electron microscopy (SEM) results of the treated surfaces. Both the metal-oxygen-carbon complex formation at the interface and the roughness induced by the oxygen treatment were found to be the reasons for the improved adhesion properties.     

A new insight into interface widths in binary polymer blends based on ortho‐positronium lifetime studies

The interface widths in two immiscible polymer blend (Poly vinyl chloride (PVC)/Polystyrene (PS)) and PVC/Ethylene Vinyl Acetate (EVA) are determined experimentally using hydrodynamic interaction approach through free volume measurement by positron annihilation lifetime spectroscopy. For comparison, the same study is performed in a miscible blend (Styrene Acrylonitrile (SAN)/Poly Methyl Methacrylate (PMMA)). The interfacial width (Δl) is evaluated from the hydrodynamic interaction (α) based on Kirkwood–Risemann theory and friction coefficient from Stokes equation. Friction at the interface of a binary blend evidences how close the surfaces of the polymer chains come or stay apart which in turn depends on the type of force/interaction at the interface. In this work, we define interface width from a different perspective of Flory–Huggins interaction approach. Measured composition dependent interface widths in the three blends studied clearly demonstrate the sensitivity of the present method. In miscible blend, high friction at the interface results in stronger hydrodynamic interaction and hence smaller interface widths (0.36–1.97 Å), whereas weak or no interaction in immiscible blends produce wider widths (2.81–25.0 Å). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Finite size gap effects on the modeling of thermal contact conductance at polymer‐mold wall interface in injection molding

Heat transfer in polymer processing by injection molding is affected by the thermal contact conductance at the interface between the polymer and the metal mold. The modeling of thermal contact conductance at such interfaces is simplified by the assumption of an isothermal condition at the two contacting surfaces. In this study we examine the validity of such an assumption for the case of an interface involving plastic (a low thermal conductivity material) and metal (a high thermal conductivity material). The study shows that at such an interface between materials of widely varying thermal conductivity, the conditions at the interface depart from the isothermal assumption, with the heat flux becoming more uniform and the temperature difference varying by a larger magnitude across the contact plane. This effect is more pronounced as the width of the gaps increases for the same area of contact. This suggests that the modeling of the contact conductance should be based on average temperatures for the contacting surfaces. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1776–1782, 2000