Flexural Stress Homogenization Effects of Interfacial Transition Layers in Modified ZrB_2-Al_2O_3/Epoxy Composites

The effect of interfacial modification on flexural strength of epoxy composites filled with modified ZrB_2-Al_2O_3 composite fillers was investigated in order to explore the stress distribution of modified composites under external load. The mechanical performance of epoxy composites filled with 0 vol%, 1 vol%, 3 vol% and 5 vol% unmodified and modified ZrB_2-Al_2O_3 fillers was characterized by three point bending(TPB) tests. The fracture surfaces of epoxy composites were observed by scanning electronic microscope(SEM). The results showed that the epoxy composite reinforced by 1 vol%modified fillers exhibited the optimal mechanical performance. According to the Von Mises stress contours simulated by finite element models(FEM) and the SEM images, it was shown that the modified ZrB_2-Al_2O_3 multiphase fillers could homogenize the stress in the epoxy composites due to the transition effect resulted from the interfacial modification layers on the surfaces of multiphase fillers. It contributed to the improvement of mechanical performance of epoxy composites further.     

环氧树脂混凝土现状与分析

环氧树脂混凝土是指以环氧树脂为主料,掺入适量的固化剂、增塑剂、稀释剂及填料作为胶粘剂;以砂、石作为骨料,经混合、成型、固化而成的一种复合材料,是聚合物混凝土的一种．环氧树脂混凝土具有强度高、韧性好、抗冲击强度大、良好的耐化学腐蚀、耐磨、耐水和抗冻性能．固化后的环氧树脂混凝土对大气、潮湿、化学介质、细菌等都有很强的抵抗力．因此,较多在较为恶劣的环境中应用,具有良好的应用价值．但由于技术、造价等诸多因素的限制,环氧树脂混凝土应用数量和范围相当有限,并且,目前环氧树脂混凝土的韧性问题仍有待解决,因此笔者在对其应用现状进行分析的同时,提出通过加入纤维、增韧剂等对其韧性等问题进行分析与探讨．     

碳纤维上电聚合噻吩对复合材料性能的影响

为了改善碳纤维与树脂基体之间的界面性能,以噻吩为单体,采用循环伏安法对碳纤维进行电化学聚合改性.利用扫描电子显微镜研究了电化学聚合改性前后碳纤维的表面结构变化,采用电脑伺服控制材料试验机测试了碳纤维增强环氧树脂复合材料的力学性能.结果表明,当噻吩浓度为0.4 mol/L时,峰值电流增加幅度最大,电聚合效果最佳.当循环次数达到60次时,碳纤维表面电化学聚合反应完全,碳纤维/环氧树脂复合材料的层间剪切强度可由13.46 MPa增加到23.79 MPa,提高约76.75%.电化学聚合后大量片层状聚噻吩聚合物在碳纤维表面聚集,碳纤维与环氧树脂基体紧密结合,界面性能明显提高.     

环氧树脂/碳纤维导热复合材料研究进展

为提高碳纤维复合材料的导热、老化以及其他力学性能,本文探讨了以环氧树脂为基体,以具有优良的力学性能的碳纤维为导热载体,制备具有良好性能的导热复合材料的制备工艺。同时,研究了碳纤维增强环氧树脂基体的热传导机制,以及近些年来环氧树脂基导热复合材料的科研现状。     

Effect of nano-silica modification on the tensile property of SMA/GF/CF/epoxy super hybrid woven fabric composites

Tensile properties of epoxy casts together with shape memory alloy (SMA), glass (GF) and carbon (CF) woven fabric reinforced epoxy matrix super hybrid composites were investigated, respectively. In order to enhance the mechanical strength of this advanced material, two categories of modifications including matrix blending and fiber surface coating by nano-silica were studied. Scanning electron microscopy (SEM) and fiber pull-out tests were adopted to complement the experimental results, respectively. Experimental results reveal that the toughness of epoxy matrix is enhanced significantly by adding 2wt% nano-silica. The failure mechanism of SMA reinforced hybrid composites is different from that of GF/CF/epoxy composites. Compared with the matrix modification, the fibers modified by coating nano-silica on the surface have better tensile performances. Moreover, the fiber pull-out test results also indicate that composites with fiber surface modification have better interfacial performances. The modification method used in this paper can help to enhance the tensile performance of the mentioned composite materials in real engineering fields.     

电工环氧树脂固化工艺研究

电工环氧树脂的固化剂选用甲基六氢苯酐（MHHPA）酸酐体系,并对固化浇注工艺及填料改性处理固化体系进行研究.固化剂、填料等改性剂的用量,固化体系的配方配比、工艺特性等方面对固化产物电学性能、机械性能都产生一定的影响.固化体系采用环氧树脂100份,甲基六氢苯酐86份,咪唑0.8份,二氧化钛3份,偶联剂KH5501份时,固化产物抗拉强度61.972 MPa,冲击强度6.172 kJ/m^2,介电常数2.268,介电损耗角正切0.001 9,体积电阻率3.076×1015.此种环氧树脂材料可适用于高压大电流开关、高压变压器绝缘子及高压组合电器等高科技领域,满足其在电工工业领域的应用要求.     

环氧树脂混凝土研究现状及其应用

环氧树脂混凝土具有强度高,韧性好,抗冲击强度大,以及良好的耐化学腐蚀、耐磨、耐水和抗冻性能.固化后的环氧树脂混凝土对大气、潮湿、化学介质、细菌等都有很强的抵抗力.本文概述了环氧树脂混凝土的组成及特性,介绍了环氧树脂混凝土复合材料的研究现状及在土木工程中的应用.环氧树脂混凝土应用效果显著,具有广泛的应用前景.     

浸泡腐蚀对HGB/EP复合材料力学性能的影响

在对复合材料的研究中,其吸水性及耐腐蚀性一直是研究的重点之一。本文通过常温和60℃吸水试验以及60℃酸、碱腐蚀试验,研究了空心玻璃微珠填充环氧树脂制成的复合材料（HGB/EP）的吸湿规律、温度对吸湿的影响以及材料在60℃下的腐蚀情况。通过研究不同配比的空心玻璃微珠（HGB）与环氧树脂制成的复合材料吸水量的大小,发现这种材料吸水量大小与微珠的填充率密切相关,不同填充比复合材料其微结构对吸水量影响甚大,且高温能提高吸湿速率和平衡吸湿量。在腐蚀试验中,发现该材料的耐酸性较差,测试后试件表现出软化现象。而酸的浓度越高,腐蚀越严重,经浸泡腐蚀的材料力学性能进一步下降。     

Analysis of Mechanical Characteristics of Fly Ash Cenospheres Reinforced Epoxy Composites

Fly ash cenospheres(FACs) as a recycling material of industrial waste has become a competitor for other inorganic particle fillers. Epoxy resin(EP) composites reinforced with different content of FACs as well as different size grading ratio were prepared. The surface modification of FACs particles was conducted before incorporating into EP matrix. The impact and flexural strengths and the flexural modulus were investigated, and the fracture surfaces of the testing samples were analyzed using SEM. Results showed that FACs had an obvious effect on the mechanical characteristics of the FACs/EP composites. With increasing weight fraction of FACs, the impact and flexural strengths and the flexural modulus of EP composite samples increased, and reached the highest values when the weight fraction of FACs reached 15 wt%. The mechanical characteristics of the FACs/EP composites however deteriorated with further increasing of FACs content. For the EP composites reinforced with different size grading ratio of FACs, the larger proportion of small FACs particles, the better mechanical properties of the EP composites. The results were analyzed from the aspect of the plastic deformation, new surface formation and fracture absorption energy. The synergistic effect of the size grading ratio of FACs was not obvious, which would be further investigated.     

Effect of sizing on the interfacial shear strength of carbon fiber/epoxy resin monofilament composite

The single fiber fragmentation test （SFFT） was used to measure the interracial shear strength （IFSS） of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.     

Effect of Epoxy Resin on Mechanical Properties of Metakaolin based Geopolymer and Microscopic Analysis

By using NaOH and Na_2SiO_3 as the activator,the mechanical properties and shrinkage of the geopolymer after incorporation of 0%,10%,20%,and 30% epoxy resin were investigated.The mechanism of epoxy resin toughening metakaolin based geopolymer was analyzed by X-ray diffraction,scanning electron microscopy and Fourier transform infrared spectroscopy.It was shown that with the increases of epoxy resin,the shrinkage performance was obviously improved and the flexural strength increased by 53.5%.The compressive strength of EGP10,EGP20,and EGP30 increased by 49.12%,57.04%,and 65.34% after curing for 28 days,respectively.There were five obvious vibration peaks of 811 cm~(-1),1 000 cm~(-1),1 050 cm~(-1),1 590cm~(-1),and 3 400 cm~(-1) in the geopolymer and the undisturbed metakaolin.More geopolymer gels were formed in the material and the microstructure was more compact.     

二氧化硅改性环氧树脂胶黏剂性能研究

采用聚氨酯增韧环氧树脂,并利用有机化的纳米SiO2为改性剂制备纳米改性环氧树脂胶黏剂.利用扫描电子显微镜( SEM)观察无机纳米粒子在聚合物基体中的分散性及复合材料的断面形貌,结果表明无机纳米粒子在复合材料中分散性良好,而且聚氨酯在环氧树脂基体中形成了“孔洞结构”.采用电子拉力机、TGA以及介电谱仪等方法测试了复合材料...     

中空玻璃微珠填充环氧树脂复合材料

讨论了用发电厂固体废料中的中空玻璃微珠填充Ｅ－４４环氧树脂制备轻质复合材料，实验详尽地考察了微珠填料，ＫＨ－５００偶联剂，固化剂（三乙基四胺，Ｔ－３１，三乙醇及液体四氢苯酐）及低聚酰胺等增韧剂等对所得的复合材料为力学性能的影响，并通过扫描电镜（ＳＥＭ）观察了材料的形态，其结果表明，偶联剂和增韧剂对复合材料的力学性能影响较大，中空玻璃微珠填充环氧树脂赋予基轻质，高强，价廉等特性。     

Synthesis and Properties of Novel Epoxidized Soybean Oil-modified Phenolic Resin/Montmorillonite Nanoeomposites

The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites(ESO-M-PR/CN)was prepared.The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N+(CH3)2C6H5Cl-,B2MP]was adopted to modify the interface between the organic and inorganic phases.The effect of the nanocomposite structure on its physical and chemical properties was discussed.During the synthesizing process of ESO-M-PR/CN,the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments.Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-M-PR/CN.The thermal and mechanical properties exhibit a significant improvement.The temperature at which a weight loss of 5%Occurs increases from 287.1℃to 402.3℃.The flexural strength increases by 25%,while the flexural modulus increases by 39%.Moreover,the properties of resin were enhanced by the effect of the inorganic nanoparticles,while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope.The particle size of inorganic montmorillonites in the modified system is less than 100 nm.     

玄武岩纤维布增强环氧树脂复合材料研究

以玄武岩纤维平纹布 (BF) 加入到环氧树脂 (EP) 中,采用模压工艺制备BF／EP 复合材料,研究加入不同层数的玄武岩纤维布对复合材料力学性能和断裂韧性的影响。实验结果表明,BF/EP复合材料的弯曲强度、冲击强度和断裂韧性明显优于环氧树脂;与未加BF的环氧树脂相比,加入三层BF后复合材料的弯曲强度提高了2.76倍,缺口冲击强度提高了19.67倍,无缺口冲击强度提高了5.94倍,KIC提高了2.97倍。     

Novel Epoxy Resin/SiO2 Nanocomposites Preparation Method Based on Diminutive Bubbles Explosion

Spontaneous agglomeration tends to occur be-tween nanometer scale particles for their high surfacefree energy[1 ,2]. The size of particle agglomeratesgranulesis always beyond nanometer scale .The spon-taneous agglomeration of nanometer scale particlesand high viscosity of epoxy resin solution madeit dif-ficult to disperse nanomaterials into polymer as theconfiguration of nanometer scale particles . How toachieve nanomaterials’symmetrical decentralizationin epoxy resin bythe configuration of n…     

隔热环氧树脂的研究及其在电缆桥架上的应用

选用导热系数很小的无机填料和增韧效果好的石棉纤维对环氧树脂进行填充改性；采用硅烷偶联剂对无机填料和石棉纤维进行表面处理，提高无机填料与聚合物基体的界面相互作用；用自行设计的方法测试材料的隔热性能，结果表明：导热系数小的无机填料明显地改善了环氧树脂复合材料的隔热性能，石棉纤维极大地提高了环氧树脂的冲击韧性，环氧树脂复合材料做成的电缆桥架已投入试运行，并且运转效果良好．     

新型环氧树脂固化剂的性能

采用亲核取代反应合成了新型含有醚酮键的芳香胺固化剂(BADK),并对其结构进行了表征。选用BADK作为固化剂,对含有联苯结构的环氧树脂和通用型环氧树脂E-51的固化条件、固化物耐热性和吸湿性进行了研究。实验结果表明:新型固化剂的使用提高了通用型环氧树脂E-51的热性能;含联苯结构的环氧树脂固化物与E-51相比,无论是热性能还是耐湿性都有很大的提高。     

环氧树脂流变学的研究进展

综述了近20年来环氧树脂流变学的研究进展。利用流变学来指导环氧树脂的最新应用,包括环氧树脂电子浆料例如底部填充胶（underfill）,环氧树脂基复合材料,环氧树脂涂料,环氧树脂黏合剂,环氧树脂与其他树脂/橡胶的复合体系等。环氧树脂体系中的填料规格、加入量以及环氧树脂的固化过程与黏度等流变指数息息相关。随着芯片等领域技术的快速发展,流变学在环氧树脂中的应用还会得到进一步加强。     

Preparation of Nano-composites Membranes with Graphic Oxides and Polylactic Acid

Organic polymer materials were used as a layer of adhesive into the graphene sheet between the layers to enhance the interaction force between the nano-structure to achieve excellent mechanical properties and barrier properties. PLA with good flowability and easy processing was selected. The mechanical properties and barrier properties of the graphene-based composites were improved by the use of PLA for good flowability, making it easy to enter the GO layer as a binder. Three methods of preparation of GO/PLA homogeneous composite membranes were designed by vacuum filtration. The experimental results show that the injection of PLA as a molecular binder into the GO layer can effectively mimic the nano-structure, and enhance the intergranular force of the graphene molecules and the compatibility with the polymer matrix.