A highly fluorinated epoxy resin. III. Behavior in composite and fiber-coating applications

The behavior of a highly fluorinated epoxy resin used as a composite matrix material with AS-4 fibers and as an AS-4 fiber coating was studied. The composite mechanical properties were obtained, and the adhesion of the matrix to the fibers was evaluated. Comparisons of uncoated and fluoropolymer coated AS-4 fibers using single fibers embedded in an Epon 828 matrix were made. Substantial improvement in fiber critical length, and therefore fiber-matrix adhesion, was observed.     

基于NOL环的高性能纤维与环氧树脂的匹配性研究

纤维与树脂的界面对复合材料的整体力学性能有着显著的影响。基于NOL环的宏观力学测试一般被用来反映复合材料的界面粘结性能,因此适用于评价纤维与树脂之间的宏观力学性能匹配性。为了探究高性能碳纤维T700SC、T800HB及高强玻璃纤维与环氧树脂的宏观力学性能匹配性,本研究首先根据GB/T 1458—2008国家标准制备NOL环试样,再借助NOL环的拉伸和层间剪切强度测试分析了高性能纤维与环氧树脂不同匹配组合宏观力学性能差异的原因,并寻找出最佳匹配组合。结果表明:玻璃纤维与环氧树脂的界面存在最佳的粘结强度,而且不同粘结强度导致拉伸强度和破坏机理不同,而碳纤维复合材料界面性能较差,容易分层破坏;T800HB与环氧树脂的宏观力学匹配性优于T700SC,环氧树脂力学性能、碳纤维的表面微观结构与性质以及环氧树脂与碳纤维之间的相互作用关系是影响界面粘结性能的根本原因。该研究在高性能纤维单向复合材料的材料选择与设计方面具有现实意义。     

玻璃纤维网布涂层用环氧改性氨基树脂合成研究

研究旨在合成环氧改性氨基树脂,并将其用作玻璃纤维网布涂层.环氧树脂先与三聚氰胺和脲在一定条件下反应,然后再与甲醛反应.这样就可以将环氧树脂引入氨基树脂中,制得环氧改性氨基树脂.这种树脂成膜后具有良好的耐碱、耐水性和硬挺度,可用作玻璃纤维网布涂层.     

环氧改性有机硅树脂的应用研究

以不同环氧改性有机硅树脂作为基料树脂,研究了不同树脂对漆膜性能的影响;通过选用不同固化体系对漆膜机械性能和耐热性做了比较;同时研究了环氧改性有机硅树脂与有机硅树脂的混溶性及影响;分别研究了该树脂配制的底、中、面涂层的常规性能及复合涂层的机械性能。同时对不同固化剂的影响和不同树脂的影响做了TG和DSC分析,结果表明,环氧改性有机硅树脂耐温性能较环氧树脂有较明显的提高,基本可用于高温涂料;环氧改性有机硅树脂可与纯有机硅树脂复配,有望形成具有更高耐温性能的涂膜。并且可通过复合固化剂的选用达到更佳的耐温性能和较好的物理机械性能。     

Characterization and role of an elastomeric interphase on carbon fibers reinforcing an epoxy matrix

Oxidized carbon fibers were coated using an on-line filament winding process with an elastomeric adduct crosslinkable and compatible with an epoxy matrix. The coating and modifications of the epoxy network were studied by dynamic mechanical measurements. Assuming that apparent activation energies of the secondary relaxation β_e of the epoxy network and main relaxation α_a of adduct are very different, it is possible at low frequencies to separate the two peaks. The composite material can be described as a three phase system: an epoxy network as matrix, carbon fibers, and a soft interlayer. The mechanical behavior of unidirectional composite materials studied by impact and bending tests is strongly dependent on the presence and the thickness of the coating at the carbon fiber surface.     

Carbon Nanotube/Carbon Fiber Multiscale Composite: Influence of Interfacial Strength on Mechanical Properties

A promising study to gain the multiscale composite by the growth of carbon nanotubes on the fibers for intralaminar and interlaminar reinforcement was carried out. The mathematical modeling and the numerical simulation of the mechanical response are helpful for the optimum design of the multiscale composite. In this paper, a multiscale modeling approach using a commercial package ANSYS was used to simulate the mechanical response of the complicated material systems. The behavior of two types of interfaces (carbon nanotube/epoxy resin, carbon fiber/equivalent matrix) was described using a cohesive zone model, and the mechanical properties of the multiscale composite were predicted accurately. The mechanism of intralaminar reinforcement was then analyzed numerically. The results reveal that the matrix-dominated properties of the multiscale composite, such as the transverse elastic modulus, increase with the increase of the carbon nanotube/epoxy resin interfacial strength.     

玄武岩纤维及其复合材料性能研究

本文研究了一种与玄武岩纤维相匹配的环氧基体及其与玄武岩纤维复合材料的性能。对比了玄武岩纤维／环氧和S2玻纤／环氧两种复合材料的性能。结果证明玄武岩纤维可替代一部份的玻璃纤维。     

Mechanical performance of various nylon 6 composites formed by in-situ polymerization of caprolactam

This paper describes the fabrication and mechanical characterization of composites made by incorporating various types of glass as bead or fiber into an activated caprolactam melt, which is then caused to anionically polymerize to a nylon 6 resin. Three types of composites are discussed and compared under separate headings: glass bead filled, sheet reinforced with a random fiberglass mat, and sheet reinforced with a unidirectional fiberglass mat that is studied under transverse loading to emphasize the role of the nylon 6 matrix resin. High molecular weight, better wet-out and adhesion to the reinforcement, and cold drawing of the polycaprolactam resin lead to homogeneous cavitation that increases composite toughness in comparison to epoxy or other nylon matrices of equivalent stiffness.     

芳纶纤维/AFR树脂复合材料界面粘结性能的研究

为了改善芳纶纤维复合材料的界面粘结性能,合成了一种新型树脂(AFR)作为基体,以未经任何表面处理的芳纶纤维作增强材料,制备了芳纶纤维/AFR复合材料。采用测定表面能、接触角、层间剪切强度、横向拉伸性能和扫描电镜观察形貌等方法,从宏观和微观等方面研究了芳纶纤维/AFR复合材料的界面粘结性能。结果表明,AFR树脂与芳纶纤维有相近的表面能,AFR树脂溶液与芳纶纤维的接触角为42.8°,而环氧树脂(EP)与芳纶纤维的接触角为68°,说明AFR树脂对芳纶纤维的润湿性优于EP树脂;芳纶/AFR复合材料的层间剪切强度、横向拉伸强度和纵向拉伸强度分别为74.64MPa、25.34MPa和2256MPa,比芳纶/EP复合材料的相应强度分别提高了28.7%、32.5%和13.4%,其复合材料破坏面的形貌也说明芳纶纤维与AFR树脂之间的界面粘结性能较好。     

Impact damage sensing of multiscale composites through epoxy matrix containing carbon nanotubes

Carbon nanotubes are used to provide increased electrical conductivity for polymer matrix materials, thus offering a method to monitor the structure's health. This work investigates the effect of impact damage on the electrical properties of multiscale composite samples, prepared with woven fiberglass reinforcement and epoxy resin modified with as‐received multi‐walled carbon nanotubes (MWCNTs). Moreover, this study addresses potential bias from manufacturing, and investigates the effectiveness of resistance measurements using two‐ and four‐point probe methods. Transmission electron microscopy and static tensile tests results were used to evaluate, respectively, the dispersion of MWCNTs in the epoxy resin and the influence of the incorporation of these nanoparticles on the static tensile properties of the matrix, and interpret results from the resistance measurements on impacted specimens. In this study, the four‐point probe method is shown to be much more repeatable and reliable than the two‐point probe method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

几种大型风力发电叶片用环氧树脂复合材料的对比分析

将风电叶片用真空灌注型环氧树脂体系MERICAN 3311A/B与同类两款产品进行了对比分析,研究了三种树脂体系对玻纤的浸润性;采用真空导入成型技术制备了复合材料板,并对复合材料的力学性能进行了研究。结果表明,MERICAN3311A/B粘度低、浸润性良好、FRP力学性能高,与纤维的匹配性良好,达到甚至某些方面已超越国内外同类进口产品的水平,能够满足风电叶片对树脂的性能要求。     

Elevated temperature testing for comparison of glass/resin composites

Static test methods were used to evaluate and compare the thermal and mechanical properties of several glass/thermoset laminated composites between 25° and 400°C. The unidirectional matrix composites consisted of phenolic-modified epoxy, epoxy novolac, epoxy, and modified phenolic resins. These materials were selected as potential alternative materials for rotary compressor vanes. Dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA) techniques were selected to evaluate elevated temperature performance. The short-beam shear test was chosen to measure interlaminar shear properties. The results indicated that an elevated-temperature matrix, such as the modified phenolic resin, may not result in optimum composite strengths. Instead, an epoxy resin reinforced with glass fibers provides a better balance between elevated-temperature performance and interlaminar shear strength. The test results of this study, in addition to being adequate for discriminating the materials for initial selection purposes, were obtained quickly and easily. Moreover, the thermal results provide a more realistic understanding of composite elevated-temperature characteristic than do those of the present standard test.     

Thermal degradation of epoxy resin reinforced with polypropylene fibers

The influence of polypropylene fibers on the thermal degradation of epoxy composites was investigated with thermogravimetric analysis. Three composites with 5, 10, or 15 wt % polypropylene fibers were prepared with epoxy as a matrix material. The polypropylene fibers, used as reinforcing materials, retarded the thermal decomposition, and increasing the weight percentage of the fiber material increased the thermal stability to a certain extent. Of the three composites, the 10 wt % polypropylene fiber/epoxy resin composite showed very good thermal stability, which was indicated by the increase in the resin decomposition temperature from 280°C for the 5 wt % polypropylene fiber/epoxy resin composite to 375°C for the 10 wt % polypropylene fiber/epoxy resin composite. The Horowitz–Metzger method was used to calculate the activation energies, and the results were tabulated. A morphological analysis was carried out with scanning electron microscopy to evaluate the dispersion of the fibers in the epoxy matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 500–503, 2007     

Investigation of the effect of different silane coupling agents on mechanical performance of basalt fiber composite laminates with biobased epoxy matrices

In recent years, it has been detected an increased interest in the development of materials from renewable resources. This trend has been intensified in the industrial sector where significant efforts have been made in this field in order to adapt these natural fibers to conventional industrial processes and applications. As a result, research has been done into developing new thermoplastic matrices which are compatible with this type of reinforcing fibers. This study evaluates the influence of different coupling agents based on silanes, on the mechanical properties of composite laminates made from a biobased epoxy resin matrix and basalt fabric by using vacuum assisted resin transfer moulding. The curing behavior of the biobased epoxy resin was evaluated by differential scanning calorimetry (DSC), gel point determination, and ionic conductivity. The evaluation of mechanical properties was done by tensile, flexural, impact, and hardness tests. Compatibility between basalt fibers and epoxy resin generally has managed to increase through the addition of silanes, after the addition of these, their mechanical properties are substantially improved compared to the sample without silane treatment, obtaining this way an easily processable material, with good properties and capable of competing with materials with petroleum‐based epoxy resins. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Surface modification of UHMWPE fibers by means of polyethylene wax grafted maleic anhydride treatment

A novel surface modification method for ultrahigh molecular weight polyethylene (UHMWPE) fibers to improve the adhesion with epoxy matrix was demonstrated. Polyethylene wax grafted maleic anhydride (PEW‐g‐MAH) was deposited on the UHMWPE fibers surface by coating method. The changes of surface chemical composition, crystalline structure, mechanical properties of fiber and composite, wettability, surface topography of fibers and adhesion between fiber and epoxy resin before and after finishing were studied, respectively. The Fourier transform infrared spectroscopy spectra proved that some polar groups (MAH) were introduced onto the fiber surface after finishing. The X‐ray diffraction spectra indicated that crystallinity of the fiber was the same before and after finishing. Tensile testing results showed that mechanical properties of the fiber did not change significantly and the tensile strength of 9 wt % PEW‐g‐MAH treated fiber reinforced composite showed about 10.75% enhancement. The water contact angle of the fibers decreased after finishing. A single‐fiber pull out test was applied to evaluate the adhesion of UHMWPE fibers with the epoxy matrix. After treatment with 9 wt % PEW‐g‐MAH, a pull‐out force of 1.304 MPa which is 53.59% higher than that of pristine UNMWPE fibers was achieved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46555.     

Improvement of interfacial shear strengths of polybenzobisoxazole fiber/epoxy resin composite by n‐TiO2 coating

Smooth polybenzobisoxazole (PBO) fiber has limited interfacial interaction with resin matrix. In this article, nano‐TiO₂ coating on PBO fiber is applied to improve the interfacial adhesion between PBO fiber and epoxy resin. The test results suggest that the PBO fiber had good interaction with epoxy resin matrix after its treatment with n‐TiO₂ sol. Nano TiO₂ particle embedded onto PBO fiber surface, acting as a chock, which made fiber implanted into the resin better. This greatly improved the shear strengths (IFSS) of PBO fiber/epoxy resin composite. It has been found that a 56% increase in interfacial IFSS has achieved without sacrificing mechanical properties of fiber. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

环氧树脂对玻璃纤维/水泥复合材料界面性能的影响

在细观单纤维拔出实验基础上,利用ANSYS有限元程序,结合生死单元方法,对环氧树脂接枝处理的玻璃纤维/水泥基复合材料纤维拔出行为进行数值模拟,获得了界面理想结合/界面非理想结合下的拔出荷载-位移曲线。讨论了环氧树脂光滑接枝与粗糙接枝对玻璃纤维/水泥基复合材料界面强度的影响,研究表明,环氧树脂接枝不仅具有良好的界面结合性,还具有良好的机械嵌合性。     

玻璃纤维网布用丙烯酸酯乳液的制备及应用研究

讨论了由苯乙烯(St)、环氧树脂(WSR6101)、邻苯二甲酸二烯丙酯(DAP)单体改性制得的丙烯酸酯乳液对玻璃纤维网布的强度保留率的影响,并通过FT-IR、光学显微镜等观测方式对树脂膜和玻璃纤维网布进行表面分析,表明在80℃的5%NaOH水溶液的作用下,树脂涂层发生了物理化学变化,同时碱液能够穿透树脂涂层并直接侵蚀玻璃纤维基体,导致粘接性能下降,从而降低了网布的机械强度。     

Graphite fiber-epoxy interphase modification by electrodeposition of poly(styrene-co-maleic anhydride) and its influence on composite properties

An electrodeposition technique has been used for the modification of the fiber-matrix interphase in graphite fiber-epoxy composites. A coating of poly(styrene-co-maleic anhydride) (SMA) polymer was electrodeposited from an aqueous solution on AU graphite fibers used as electrodes in an electrolytic cell. Different electrocoating parameters were initially used to establish the optimum conditions to achieve thin uniform coatings suitable for functioning as interphases in composites reinforced by the coated fibers. The interfacial shear strength (IFSS), evaluated by a single-fiber composite technique, showed that the SMA coating resulted in an improvement of about 50% in IFSS compared with the commercially treated fibers (AS). This was achieved without sacrificing impact strength. Evidence of good epoxy penetration into the coating was obtained by the use of electron microprobe line scans for bromine across the diameter of a filament in a single fiber composite-the bromine introduced through the use of a brominated epoxy resin. The observed improvement in the fiber-matrix interfacial shear strengths is dependent on the co-monomer ratio in electrodeposited SMA.     

低粘度双酚A型环氧树脂的合成制备及应用

环氧树脂是一种具有优良的物理机械性能,电绝缘性和粘接性能热固性树脂,被广泛应用于涂料、胶粘剂、复合材料、模压材料和浇铸材料等领域中。其中,双酚A型环氧树脂占到总体环氧树脂用量的90%左右,但常温下的高粘度限制了它的应用。目前,低粘度双酚A型环氧树脂的制备和研究已成为研究者们所关注的重点之一。本文着重介绍了低粘度双酚A型环氧树脂的合成方法及得到的树脂粘度性质。