嵌段共聚偶联剂对玻璃纤维增强聚丙烯界面粘结的影响

合成了苯乙烯与丁二烯及含C==C硅烷的嵌段共聚偶联剂。采用该嵌段共聚物对玻璃纤维进行了表面处理,通过单丝临界长度法测定了玻璃纤堆增强聚丙烯的界面剪切强度。结果表明：采用嵌段共聚偶联剂对玻璃纤维进行处理,可以有效地改善玻璃纤维增强聚丙烯的界面粘结,其界面改性效果优于普通小分子偶联剂;嵌段共聚偶联剂的分子结构对界面粘结有影响,采用适当的嵌段长度,可获得较好的界面粘结;在基体树脂中加入功能化聚丙烯。可改善复合体系的界面粘结;基体树脂分子链较长或流动性好、粘度低,有利于基体与歼堆的的界面粘结。     

环氧树脂体系固化反应及其复合材料介电性能

环氧树脂是一类综合性能优异的热固性高分子材料，作为胶粘剂、复合材料用树脂基体、涂料等形式广泛应用于电子电气、机械制造、化工防腐、航空航天等众多领域中，成为各工业领域中不可缺少的基础材料。本文综述了本研究室在咪唑／环氧树脂体系，稀土有机化合物、叔胺羧酸复盐／酸酐／环氧树脂体系，氰酸酯／环氧树脂体系，硼胺络合物／环氧树脂体系的固化反应机理、固化反应动力学及其固化物结构与性能关系，纤维含量、排列方向、偶联剂种类等对玻璃纤维增强环氧树脂基复合材料及其界面介电性能的影响等6个方面的研究进展。     

聚丙烯混杂复合体系的界面和力学性能

从刚性粒子增韧聚合物体系的界面层性质入手，研究了带有柔性分子链界面改性剂包覆的高岭土（Ｋａｏｌｉｎ）刚性粒子增韧的，短切玻纤（ＧＦ）增强的聚丙烯（ＰＰ）混杂复合体系的微观结构，结晶性质，ＰＰ／Ｋａｏｌｉｎ／ＧＦ混杂复合材料的加工流动性及力学性能．实验结果表明，所合成的界面改性剂对ＰＰ／Ｋａｏｌｉｎ复合材料有显著的增韧效果；加入少量的短切玻纤可以弥补因界面改性剂引入而引起的ＰＰ／Ｋａｏｌｉｎ复合材料强度和模量降低的缺点；经界面改性剂包覆的高岭土刚性粒子和短切玻纤同时加入ＰＰ，混杂复合后，ＰＰ复合材料的冲击韧性大幅度提高，材料的强度和模量不降低．这个结果不仅在较低的Ｋａｏｌｉｎ含量下，而且可在Ｋａｏｌｉｎ含量为５０％（ｗｔ％）的高填充量下也得以实现     

乙醇对碳纤维复合材料界面的影响

为了研究碳纤维复合材料(CFRPs)界面结构在乙醇作用下的变化,通过原位观察树脂和纤维尺寸,提出了一种CFRPs界面表征方法。利用碳纤维和环氧树脂制备横截面试样和层板试样,并用乙醇对其进行处理,接着采用环境可控原子力显微镜(ECSPM)对试样界面附近形貌进行原位升温表征,并通过短梁剪切试验分析试样的层间剪切性能。结果表明,经乙醇处理后,CFRPs界面附近树脂发生膨胀,并且试样在加热过程中发生显著的树脂收缩和纤维膨胀;乙醇处理对CFRPs的层间剪切强度和失效模式的影响并不明显。     

偶联剂对玻璃纤维/环氧树脂基复合材料介电性能的影响

偶联剂对玻璃纤维／环氧树脂基复合材料介电性能的影响陈平刘胜平张明艳（哈尔滨理工大学电工材料系哈尔滨１５００４０）关键词环氧树脂基复合材料，介电性能，偶联剂，浸润性玻璃纤维／环氧树脂基复合材料（ＧＦＲＰ）具有优异的电气和力学性能．然而孔隙的存在强烈地...     

芳烷基酚树脂玻纤增强材料性能的研究

用芳烷基酚树脂与玻璃纤维布制成纤维增强材料，研究了引材料的高温热老化性能和在３０－５０％热沸太航热醋和含氯离子的热沸醋酸下的腐蚀性能。     

碳纤维表面改性研究进展

碳纤维因其优异的综合性能常被用作树脂基体的增强材料.然而由于碳纤维与树脂基体之间的界面结合性能较差,其增强的复合材料的力学性能往往与理论值相差甚远,因此必须对碳纤维进行表面改性,以提高其与聚合物基体的界面粘结性能.本文作者综述了国内外关于碳纤维表面改性技术的研究进展,概述了涂层法、氧化法、高能辐射法等改性方法对碳纤维增强复合材料界面强度的改性效果.     

热塑性碳纤维复合材料界面研究

综述了热塑性碳纤维复合材料界面研究的新进展。指出由于热塑性复合材料基体树脂是高聚物,熔体牯度很大,很难均匀地分布在增强纤维之中并与纤维形成良好浸溃,存在界面结合不良的问题,因此对其界面优化设计要有一个新的认识。界面上没有化学键结合,界面结合不良,但只靠短化学键的连接,界面结合也不良,必须有一个强韧结合的界面,既有强结合又具有界面松弛能力,同时又能与高聚物基体融合的界面缓冲层的优化设计。对于Plueddemann偶联剂的概念中偶联剂“必须成为树脂的一部分”,作者认为最好的方法是就是树脂本身,即它既与纤维化学键键合,又与树脂良好相容,界面匹配。这将是热塑性复合材料界面层设计的一种新方法。     

氨基硅烷/马来酸酐接枝聚丙烯界面化学反应的研究

利用溶剂萃取与红外光谱（IR）、光电子能谱（XPS）技术研究了化学键接在玻璃纤维表面的硅烷偶联剂与接枝聚丙烯间的界面化学反应。结果表明：溶剂萃取可以除去玻璃纤维/树脂界面区物理结合的聚合物基体,减少基体信号的影响,在此基础上,利用IR、XPS可以直接证明氨基硅烷（APS）与马来酸酐接枝聚丙烯（MA-g-PP）间发生了界面化学反应,生成了含酰胺基的反应产物。进一步对不同化学状态的N1s的XPS定量分析发现,尽管APS在玻纤表面以开环直链和以氢键结合的环状两种结构形式存在,但在界面上主要是无环开链结构中的氨基与酸酐发生反应。     

热致液晶聚合物对短玻璃纤维增强聚丙烯加工性、结构与性能的改善

<正> 短切玻璃纤维增强的热塑性复合材料具有加工简便,生产周期短,可以反复加工等优点,因此得到了广泛应用。但短切玻璃纤维会给加工成型带来困难,主要在于纤维对加工设备的磨损,以及由于纤维的加入增大了熔体的粘度等。如果提高加工温度来降低粘度又会导致高聚物降解。几年前Kiss和Isayev提出用热致液晶聚合物(TLCP)的刚性棒状分子链作增强剂与被增强基体熔融共混,在加工中TLCP原位形成增强纤维,形成原位复合材料。原位复合材料中由于TLCP的流变性质,使其共混物的加工粘度     

The nature of the structural gradient in epoxy curing at a glass fiber/epoxy matrix interface using FTIR imaging

The curing process of an epoxide system was studied at the interface formed between a silane-coated glass fiber and an epoxy matrix. The gradient in the structure of the epoxy resin as a result of the cure process at the fiber/matrix interfacial region was monitored by FTIR imaging. For comparison, the epoxy curing at the interface formed between the epoxy resin and (a) an uncoated glass fiber and (b) a polyorganosiloxane (obtained from the silane used for the glass-fiber coating) were also monitored. Chemically specific images of the OH and the H-N-H groups near the interface region were obtained. These images suggest that there is a chemical gradient in the structure of the matrix from the fiber surface to the polymer bulk due to different conversions. The basis of the different kinetics of the curing reactions is a result of amino group inactivation at the interface. This deactivation translates into an off-stoichiometry of the reaction mixture, which is a function of the distance from the surface of the glass fiber.     

Kinetic study of epoxy curing in the glass fiber/epoxy interface using dansyl fluorescence

The fluorescence response of the dansyl chromophore has been used to study the kinetic of epoxy curing processes. With this new method, comparison between the curing at the interface of a glass fiber/epoxy and in the epoxy bulk of a composite material was studied. The effect of two glass fiber surface treatments was investigated. Commercial E-glass fibers were surface coated with 3-aminopropyltriethoxysilane (APTES) and 3-aminopropylmethyldiethoxysilane (APDES). Fluorimetry (using fluorescent labels) and FT-NIR (Fourier transformed infrared spectroscopy in the near range) techniques were used to monitor the curing process in these composite materials. From the analysis of the data obtained, different simple kinetic models were discussed and apparent activation energies were obtained. Furthermore, from those techniques the respective results were compared to obtain complementary information. Independently of the sample and the technique used for the kinetic analysis, no variation of the activation energy of the epoxy curing reaction was found, which suggests that there are no changes in the mechanism of the reaction along the process. Fluorescence from dansyl located at the glass fiber/epoxy interface reflected that the kind of reinforcement treatment clearly affects the epoxy curing process exactly in that region. However, when analytical response comes from the whole system the mechanism of the reaction does not seem to change with the silane coating used although is quite different in comparison with the process at the interface.     

A novel dynamic constitutive micromechanical model to predict the strain rate dependent mechanical behavior of glass/epoxy laminated composites

In the present research, a novel dynamic constitutive micromechanical (DCM) model was developed to predict the strain rate dependent mechanical behavior of laminated glass/epoxy composites. The present model is an integration of the generalized strain rate dependent constitutive model as a constitutive model for the neat polymer, the plasticity model of Huang as a micromechanical model, and dynamic progressive failure criteria. This model is able to predict the longitudinal and transverse tensile and in-plane shear behaviors of unidirectional glass/epoxy composites with arbitrary fiber volume fractions at arbitrary strain rates. The present model can also predict the stress-strain behavior of laminated composites with different layups and fiber volume fractions at arbitrary strain rates. A comparison between the results predicted by the present model and the available experimental data showed that the model predicts the strain rate dependent mechanical behavior of glass/epoxy composites with very good accuracy.     

Temperature effect during humid ageing on interfaces of glass and carbon fibers reinforced epoxy composites

Weight change behavior of fiber-reinforced polymer composites in humid and thermal environments appears to be a complex phenomena. The state of fiber/matrix interface is believed to influence the nature of diffusion modes. A significant weakening often appears at the interface during the hygrothermal ageing. It effects the moisture uptake kinetics and also the reduction of mechanical properties. The importance of temperature at the time of conditioning plays an important role in environmental degradation of such composite materials. An attempt has been made here to evaluate the deleterious effect of temperature on shear strength of carbon/epoxy and glass/epoxy composites during hygrothermal conditionings. Mechanical tests were conducted at room temperature to assess the effectiveness of the relaxation process in the nullification of environmentally-induced damage in the composites.     

The Structure and Moisture Stability of the Matrix Phase in Glass-Reinforced Epoxy Composites

The utilization of reinforced plastic composites is generally limited by their sensitivity to long-term environmental exposure. Glass-reinforced thermosetting polymers in particular are detrimentally affected, reversibly and/or irreversibly, by exposure to water vapor or liquid water. A reinforced composite consists of three mutually interacting regions: fiber, matrix, and the fiber/ matrix interface. Each region may, for purposes of convenience, be further subdivided according to its location or properties. Most common is the listing of regions comprising the “interface”: glass/ coupling agent interface, the coupling agent polymer itself, and the coupling agent/matrix interface. Even the amorphous cross-linked matrix nearby the filler is believed to possess properties dissimilar to those of the bulk. Each region and subregion is altered by moisture exposure to some extent; at this time studies on composite stability still focus on determining which regions are most affected by the environment and on the mechanisms of those effects, as well as on devising systems with minimal environmental sensitivity. Moisture effects on glass-reinforced epoxy composites, the most common of the reinforced plastic systems, will be emphasized in this paper. Multifunctional epoxy resins are typically cross-linked by acid anhydrides, forming 3-D polyesters, and by amine functional compounds, yielding 3-D amine-ether polymers. There are many structural varieties; the same hydrothermal degradation mechanisms apply universally, and hereafter the term “epoxy” matrix will be employed. The stability of the glass reinforcement itself and of the interface will first be briefly reviewed as a prelude to a more detailed consideration of the reversible and irreversible moisture effects on the cross-linked epoxy matrix.     

ELECTRODEPOSITION OF POLYMERS ON CARBON FIBERS

Styrene-co-maleic anhydride, vinyl acetate-co-maleic anhydride, methyl methacrylate-co-maleic anhydride copolymers were deposited on the surface of carbon fibers by an electrodcposition technique. The anion-free radical mechanism of this process and the physical adhesion to the surface were preliminarily confirmed. The adhesion at fiber-resin matrix interface in carbon fiber reinforced plastics was improved by the electrodeposited polymer interlayer and the shear failure occurred mainly in the matrix. Interlaminar shear strength of the unidirectional carbon fiber reinforced epoxy composite is increased from about 600 kg/cm~2 to 1000 kg/cm~2 by electrodeposition of polymers and the strength loss of the composite which has been immersed in boiling water for 100 hrs is decreased.     

Improved mechanical properties of epoxy‐based composites with hyperbranched polymer grafting glass‐fiber

A glass‐fiber, grafted by hyperbranched polymer with hydroxyl group (GF‐HBPH), reinforced epoxy‐based composite was evaluated for mechanical properties and compared with the neat epoxy and silanized glass‐fiber, GF‐APS. The epoxy/GF‐HBPH composites were studied by attenuated total internal reflectance infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, thermal gravimetric analysis, mechanical properties analysis, and field emission‐scanning electron microscopy. The results showed that the incorporation of GF‐HBPH could simultaneously enhance the mechanical properties of the epoxy composites. Field emission‐scanning electron microscopy images of the fracture surfaces of the test specimens were used to support the results and conclusions. Copyright © 2016 John Wiley & Sons, Ltd.     

The dynamic mechanical behavior of random-in-plane short fiber-reinforced epoxy resin composites

In the present paper, the dynamic mechanical properties of random-in-plane short fiber-reinforced epoxy resin composites were studied by using a rheometrics solids analyzer. The three-point bend testing of the four composites (glass fiber/913 epoxy resin, glass fiber/924 epoxy resin, carbon fiber/913 epoxy resin and carbon fiber/924 epoxy resin) was carried out over temperatures from −100°C to 200°C at a frequency of 10 Hz and strain 0.05%. The composites based on 924 epoxy resin, which has been designed specially for high temperature applications, have less energy loss than the 913 epoxy resinbased composites. For the same resin, the carbon fiber-reinforced composites have less energy loss than the glass fiber-reinforced composites. All the composites have less energy loss than their corresponding matrices; the greater the fiber content, the lower the energy loss. The beta transition of 913 epoxy resin has been shifted to a higher temperature after being reinforced. It was shifted from −50°C to −30°C after being reinforced with glass fiber and made a diffuse shoulder-like peak commencing at −30°C after being reinforced with carbon fiber. The 924 epoxy resin has undergone the same change in beta transition as the 913 resin, though to a smaller extent. The phenomenon suggested that interactions between the macromolecules of the epoxy resins and the molecules along the fiber's surface.     

环氧树脂和玻璃粘合的研究

以断裂力学方法研究了环氧树脂与玻璃的粘合及添加偶联剂的影响.测定了该粘合在80℃水中不同浸泡时间、不同偶联剂、不同偶联剂浓度和不同pH值的断裂能.利用Andrews普适断裂力学理论求得了破坏单位截面积界面上原子键合的界面能θ_o及水对θ_o的影响符合一级反应规律.比较了θ_o值与界面范得华相互作用能.推算出环氧树脂-玻璃粘合中至少有部分是主价键合.