磨碎玻璃纤维增强环氧树脂复合材料的制备及力学性能研究

用硅烷偶联剂对磨碎玻璃纤维表面进行改性,并制备玻璃纤维/环氧树脂复合材料,采用超声分散对复合材料分散处理,探讨不同磨碎玻璃纤维粉质量比对环氧树脂基复合材料压缩、拉伸性能的影响。研究表明,添加磨碎玻璃纤维后,环氧树脂的强度和硬度显著增强。当磨碎玻璃纤维掺量在15%~25%之间时,复合材料的综合力学性能最好,其压缩强度、压缩模量、拉伸强度最高达到67.1 MPa、1.68 GPa、57.6 MPa,与纯环氧树脂相比提高了24%、35%、34%;断裂伸长率随着掺量的增加逐渐降低,当含量达到30%时比纯环氧树脂的降低了48%,表明添加玻璃纤维粉后环氧树脂脆性增强。目数小粒径较大的玻璃纤维粉对环氧树脂力学性能增强效果更优,但影响程度不如含量对复合材料力学性能的影响大。     

玻璃纤维/环氧树脂泡沫夹层板的热解动力学

使用DTG-60(AH)热重分析仪分析了玻璃纤维/环氧树脂泡沫夹层板在不同升温速率和不同氧含量条件下的热分解特性。结果表明,在空气中玻璃纤维/环氧树脂泡沫夹层板的热分解反应可分为三个阶段。随着升温速率的提高,热分解反应的初始反应温度、终止反应温度以及最大质量损失速率温度均向高温方向移动。氧含量的降低对热分解的第三阶段有较大的影响。采用Flynn-Wall-Ozawa法和Starink法进行热解动力学分析,得到玻璃纤维/环氧树脂泡沫夹层板的表观活化能。     

环氧树脂复合材料的制备及力学性能

通过配方设计,以硅烷偶联剂改性的空心玻璃微珠(HGB)为填料,端羧基液体丁腈橡胶(CTBN)为增稠剂和增韧剂,环氧树脂(EP)为基体,经变温分段固化技术制备环氧树脂/端羧基丁腈橡胶/空心玻璃微珠(EP/CTBN/HGB)三元泡沫复合材料并研究其力学和流变性能。结果表明,CTBN使得复合材料由脆性断裂变为韧性断裂;CTBN劣化了复合材料模量而HGB弥补了复合材料模量;当CTBN、HGB含量分别为12%(质量分数)和30%(体积分数)时,三元复合材料的冲击、弯曲、拉伸强度及弯曲模量均优于纯EP。另外,纯环氧树脂和EP/CTBN共混物的黏度呈现出牛顿流体的流变行为,而三元共混物的黏度表现出明显的剪切变稀现象。     

缝合参数对泡沫夹层结构复合材料力学性能的影响

采用真空辅助树脂注射(VARI)成型工艺制备不同缝合方式和缝合密度的缝合泡沫夹层复合材料,研究缝合参数对平面拉伸、三点弯曲、芯子剪切以及滚筒剥离性能的影响。结果表明:缝合使泡沫夹层复合材料的平面拉伸强度和芯子剪切强度明显降低,可以改善弯曲性能并大幅提高滚筒剥离性能,改进锁式缝合方式优于临缝式缝合方式;适当地增加缝合行距对力学性能有一定的积极作用,但不利于滚筒剥离性能的提高;与未缝合泡沫夹层复合材料相比,当缝合密度为30 mm×10 mm时,改进锁式缝合泡沫夹层复合材料的平拉强度和芯子剪切强度分别降低了14.75%和24.79%,弯曲强度和平均剥离强度分别提高了7.96%和80.78%。     

石墨烯/环氧树脂复合材料的制备及力学性能

分别通过超声共混法和原位还原法制备了石墨烯/环氧树脂复合材料。利用X射线光电子能谱(XPS)、X射线衍射(XRD)、光学显微镜和扫描电子显微镜(SEM)对复合材料的结构进行了表征,并对其力学性能进行了测试。结果表明,原位还原法制备的石墨烯/环氧树脂复合材料中,氧化石墨烯已经被成功地还原为石墨烯,并且石墨烯具有良好的分散性。力学性能测试结果表明,两种方法制备的复合材料的力学强度较纯环氧树脂明显提高。当石墨烯的量为m(GO)/m(EP)=0.3/100时,超声混合法制备的石墨烯/环氧树脂复合材料的拉伸强度和弯曲强度分别最大提高约29.2%和1.4%;而原位还原法制备的石墨烯/环氧树脂复合材料的拉伸强度和弯曲强度分别最大提高约40.5%和9.4%。     

织物结构对玄武岩织物/环氧树脂复合材料力学性能的影响

采用三种不同结构玄武岩织物(单向/平纹/2.5维),通过树脂传递模塑成型工艺(RTM)制备了玄武岩织物增强环氧树脂复合材料。通过拉伸和弯曲试验,研究了织物结构对复合材料力学性能的影响,探讨了不同织物结构玄武岩织物增强环氧树脂复合材料的损伤破坏机制。结果表明:织物结构形式对复合材料的力学性能有较大影响,单向玄武岩织物复合材料的拉伸性能最好,试样的拉伸断口相对齐平,分层现象不明显;2.5维玄武岩织物复合材料弯曲性能最好,且纬向弯曲性能优于经向。2.5维织物增强复合材料的结构整体性较好,受到拉伸和弯曲载荷不会产生分层破坏。根据扫描电子显微镜(SEM)断面分析可以判定,玄武岩织物/环氧树脂复合材料拉伸和弯曲加载过程中的损伤类型主要为织物中纤维的断裂及纤维-树脂的界面脱粘。     

环氧树脂复合泡沫材料的压缩力学性能

对空心玻璃微珠填充环氧树脂复合泡沫材料进行了准静态压缩实验, 研究了材料的宏观压缩力学性能, 并提出了弹性模量和屈服强度的预测公式。此外, 对压缩试件的断口进行了宏、细观观察, 研究了材料的压缩破坏机理。结果表明, 复合泡沫材料在压缩过程中, 具有普通泡沫材料的应力-应变曲线的典型特征, 在应变为2 %左右时材料发生屈服, 在应变大于30 %后发生破坏。此外, 材料的杨氏模量和强度均随密度的减小而下降, 预测公式给出的结果与实验值基本一致。压缩试件断口的宏、细观观察表明, 复合泡沫材料主要的破坏形式为剪切引起的弹塑性破坏。      

纳米碳管/环氧树脂复合材料的制备及力学性能

报道了利用催化裂解法制备的纳米碳管合成环氧树脂复合材料的技术及工艺条件。利用透射电子显微镜(TEM)对制备的复合材料进行观察表征;通过拉伸及压缩实验对纳米碳管/环氧树脂复合材料的力学性能进行了测试。实验结果表明:纳米碳管的加入可以明显地改变环氧树脂基体材料的力学性能。      

石墨烯/环氧树脂复合材料的制备与力学性能

通过对氧化石墨热膨胀还原并用超声分散制备了石墨烯,并对所得产物进行分析表征。用超声分散和模具浇注成型法制备了石墨烯/环氧树脂纳米复合材料。研究了石墨烯含量对石墨烯/环氧树脂复合材料力学性能和断面形貌的影响,分析了石墨烯对环氧树脂的增强机理。结果表明,随着石墨烯含量的增加,石墨烯/环氧树脂复合材料的拉伸强度及模量先增加后减小;当石墨烯的质量分数为0.1%时,复合材料的拉伸强度达到最大值60.9MPa,比纯环氧树脂提高了16.88%;当石墨烯的质量分数为0.5%时,复合材料的拉伸模量达到最大值2833.3MPa,比纯环氧树脂提高了48.29%。     

纳米增韧三维正交玻璃纤维机织物增强环氧树脂复合材料的力学性能

为研究纳米改性对复合材料力学性能的影响,以纳米黏土改性环氧树脂与固化剂混合胶液为基体,以三维正交机织玻璃纤维织物为增强体,利用真空辅助树脂传递模压工艺（Vacuum assisted resin transfer molding,VARTM）,制备纳米增韧三维正交玻璃纤维机织物增强环氧树脂复合材料。分别测试不同质量分数（1wt%、2wt%、3wt%、4wt%）纳米黏土改性复合材料沿0°和90°方向的弯曲和拉伸性能。结果表明:当纳米黏土质量分数为1wt%时,复合材料弯曲强度最大,沿0°和90°方向的弯曲强度分别增大了约7.21%和13.71%,弯曲模量分别增大了约5.69%和16.64%。当纳米黏土质量分数为3wt%时,复合材料拉伸强度最大,沿0°和90°方向的拉伸强度分别增大了约24.96%和27.93%,拉伸模量分别增加了约21.35%和13.26%。这是由于纳米黏土呈纳米尺度以片层状分散于环氧树脂中,增加了两相间的接触面积,提高纤维/树脂界面的结合力,进而增强了复合材料的力学性能。      

Effects of fiber surface treatments on mechanical properties of epoxy composites reinforced with glass fabric

In this study, effects of fiber surface treatments on mechanical behavior and fracture mechanism of glass fiber/epoxy composites were investigated experimentally. To change the composition of the glass and regenerate to the hydroxyl groups, activation pretreatment of heat cleaned woven glass fabric was performed using (v/v) HCl aqueous solution at different concentrations before silane treatment. The treatment of silanization of heat cleaned and acid activated glass fibers with γ-glycidoxypropyltrimethoxysilane were performed. In this work, short beam shear test has been conducted to determine the performance of the acid treatment and the silane treatment in terms of the interlaminar shear strength. The silane coating on the heat cleaned glass fibers increased the interlaminar shear strength of the composite. However, the silane coating on the acid activated glass fibers did not improve the interlaminar shear strength of the composite. In addition, the strengths of the glass fabric specimens in tension and flexure were investigated. When the glass fibers are first treated with HCl solution and then with silane coupling agent, the tensile strengths of the composites decreased significantly. Scanning electron photomicrographs of fractured surfaces of composites were performed to explain the failure mechanisms in the composite laminates broken in tension.     

玄武岩纤维-碳纤维混杂平纹织物增强环氧树脂基复合材料的制备与力学性能

对以平纹织物为增强体的混杂纤维复合材料（HFRP）的刚度和强度进行研究。设计热压工艺并制备7组具有不同混杂比的玄武岩纤维-碳纤维（玄-碳）混杂增强环氧树脂基复合材料试样进行拉伸试验。基于平纹织物的结构特征,对传统混合定律加以修正,提出以平纹织物为增强体的HFRP刚度估算模型。基于HFRP层合板的破坏机制,提出材料仅发生一次破坏的临界混杂比,并分成三个混杂比范围给出强度估算模型。最终以体现分散度的混杂效应系数对估算结果加以修正。结果表明：计算值与试验值近似,预估模型计算所得临界混杂比与试样拉伸试验时的应力-应变曲线分析结果相符,模型可为今后的实际应用提供理论依据。本文提出的预估方法可以反应混杂比和分散度对平纹织物为增强体的HFRP强度和刚度的影响,扩展了混合定律的应用范围。     

Preparation and mechanical properties of carbon nanotube grafted glass fabric/epoxy multi-scale composites

In the present paper, carbon nanotubes (CNTs) were chemically grafted onto surfaces of the amino silane treated glass fabric by a novel chemical route for the first time to create 3D network on the glass fibers. The chemical bonding process was confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. The glass fabric/CNT/epoxy multi-scale composite laminates were fabricated with the CNT grafted fabrics using vacuum assisted resin infusion molding. Tensile tests were conducted on fabricated multi-scale composites, indicating the grafting CNTs on glass fabric resulted a decrease (11%) in ultimate tensile strength while toughness of the multi-scale composite laminates were increased up to 57%. Flexural tests revealed that the multi-scale composite laminates prepared with CNT grafted glass fabric represent recovering after first load fall. The interfacial reinforcing mechanisms were discussed based on fracture morphologies of the multi-scale composites.     

Evaluation of mechanical properties of banana and sisal fiber reinforced epoxy composites: Influence of glass fiber hybridization

In this work, the effect of glass fiber hybridization with the randomly oriented natural fibers has been analyzed. The banana (B), sisal (S) fibers were chopped and woven E-glass (G) synthetic fibers were reinforced with epoxy matrix. Nine different kinds of laminates were prepared in the following stacking sequence of B, S, BS, G/B/G, G/S/G, G/BS/G, G/B/G/B/G, G/S/G/S/G and G/BS/G/BS/G. Mechanical properties like tensile strength, flexural strength and impact strength were evaluated and compared. Interfacial analysis was also carried out with the help of Scanning Electron Microscope (SEM) to study the micro structural behavior of the tested specimen. It was observed that the addition of two and three layer of glass fiber can improve the tensile strength by a factor of 2.34 and 4.13 respectively. The flexural properties were enhanced on banana–sisal fiber with two layers of glass fibers rather than three layers and the laminate with sisal and three glass ply offers better impact strength.     

Dielectric properties and noncontact damage detection of plain-woven fabric glass fiber reinforced epoxy matrix composites using millimeter wavelength microwave

Electromagnetic wave reflections from glass fiber reinforced epoxy matrix composites with 0°/90° and ±45° fiber oriented plain-woven glass fabric (PW-GFRP-0/90, PW-GFRP-±45) at incident angles of 30°, 40° and 50° were measured in the frequency range 50-75 GHz using a free-space reflection measurement system. The complex dielectric constants of both composites were calculated using a simple transmission line theory. The complex dielectric constants of PW-GFRP-0/90 and PW-GFRP-±45 are similar and were measured to be ε′ = 4.61 ± 0.01 and ε″ = 0.16 ± 0.002, respectively.The damage stored in PW-GFRP-0/90 and PW-GFRP-±45 was also evaluated by dielectric constant changes using the same system at an incident angle of 30°. For both composites, ε′ decreased with increasing applied stress and damage parameter. The dielectric constant change is effective for detecting the damage stored in composites and can be used to quantitatively evaluate the damage.     

短玻纤增强丙烯腈-丁二烯-苯乙烯共聚物的制备及性能

以丙烯腈-丁二烯-苯乙烯共聚物(ABS)及短玻璃纤维(SGF)为原料, 以苯乙烯-马来酸酐共聚物(SMA)和环氧树脂(EP)为界面相容剂, 制备了SGF/SMA-EP-ABS复合材料。用扫描电镜(SEM)、 动态力学热分析(DMTA)等研究了界面相容剂对SGF增强ABS复合材料力学性能及界面粘结性能的影响。结果表明:加入SMA或EP, SGF增强ABS复合材料的力学性能明显提高; SMA与EP同时加入具有明显的协同效果, 使复合材料的性能更为优越。当SGF加入质量分数为30%时, SGF/SMA-EP-ABS复合材料的拉伸强度、 弯曲强度、 冲击强度较未添加界面相容剂时分别提高了56%、 42%、 79%。SEM和DMTA测试表明, 加入SMA和环氧树脂后, SGF与ABS基体之间的界面粘结性能得到很大改善。      

三维编织超高分子量聚乙烯纤维-碳纤维混杂增强环氧树脂复合材料摩擦磨损性能

以超高分子量聚乙烯纤维(UHMWPE)-碳纤维(CF)三维混杂编织体为增强体,环氧树脂(ER)为基体,通过树脂传递模塑(RTM)工艺制备了三维编织混杂复合材料,研究了其摩擦磨损性能了,并采用混合正压力模型对摩擦系数进行了预测。结果表明,在纤维总体积含量一定的情况下,随着CF体积含量的增加,复合材料的摩擦系数增大,而其比磨损率降低。UH_3D/ER复合材料的磨损机制以粘着磨损为主,CF_3D/ER复合材料则以磨粒磨损为主,混杂复合材料的磨损机制主要取决于CF与UHMWPE纤维的相对含量 ,通过调节UHMWPE纤维和CF的体积比例可实现对复合材料摩擦磨损性能的有效调控。采用的计算模型可较好地预测UH_3D/ER的摩擦系数。     

Improved mechanical property of foam glass composites toughened by glass fiber

The mechanically improved foam glass composite toughened by glass fiber was prepared by sintering technique, using waste sodium-calcium silicon flat glass powder as main raw materials. In this study, the preparation and properties of the samples were characterized by differential thermal analysis (DTA), field-emission scanning electron microscopy (FESEM) and mechanical property test. The specific strength of the composite was defined for the first time, and applied into the investigation of mechanical property. The results show that the specific improved bending strength of 10.45-22.26 MPa/(g cm^− 3), and the specific compressive strength of 30.45-34.34 MPa/(g cm^− 3) can be displayed when sintered at 790-815 °C with the addition of 5-25 wt.% glass fiber. Good correlations between the microstructure (in particular the fiber distribution), the high specific strength and the high modulus of elasticity of glass fibers.     

Effect of fiber surface texture on the mechanical properties of glass fiber reinforced epoxy composite

The effect of fiber sizing and surface texture on the strength and energy absorbing capacity of fiber reinforced composites has been evaluated at two length scales using the macromechanical quasi-static punch shear test and the micromechanical microdroplet test methods. E-Glass/SC-79 epoxy composite laminates with four different fiber sizing formulations with various degrees of chemical bonding and surface texture have been investigated. The failure modes during perforation and different energy dissipating damage mechanisms were identified and quantified. The punch shear strength and the total energy absorption per unit volume of composite with hybrid sizing have increased by 48% and 100% over the incompatible sizing. These results showed linear correlations with the interphase properties reported earlier by the authors (Gao et al., 2011) and provided a methodology for developing new sizing by tailoring chemical bonding and the fiber surface texture at the fiber–matrix interphase for improving both strength and energy absorption of composites.