Mechanical Properties of Phenolic-Resin Composites Reinforced with CF/BF Interlayer Hybrid Fibers

Phenolic-resin composites reinforced with carbon fiber（CF） and basalt fiber（BF） interlayer hybrid fibers plain fabric were fabricated.The tensile strength,compressive strength and interlaminar shear strength of the prepared composites were studied.The results indicated that hybrid fibers reinforced composites possessed the advantages of both CF and BF.When resin content was 35% by volume fraction,the comprehensive mechanical performance of BF/CF reinforced phenolic resin composites reached the optimal values with the warp and weft direction tensile strength,compressive strength and interlayer shear strength being 252 MPa and 487 MPa,105 MPa and 129 MPa,21 MPa and 20 MPa,respectively.The scanning electron microscope（SEM） observations showed that the BF/CF hybrid fibers reinforced composites had better interfacial adhesion.

Effect of Hybridization on the Mechanical Properties of Pineapple Leaf Fiber/Kenaf Phenolic Hybrid Composites

In this study,pineapple leaf fiber(PALF),kenaf fiber(KF)and PALF/KF/phenolic(PF)composites were fabricated and their mechanical properties were investigated.The mechanical properties(tensile,flexural and impact)of the PALF/KF/PF hybrid composites were investigated and compared with PALF/KF composites.The 3P7K exhibited enhanced tensile strength(46.96 MPa)and modulus(6.84 GPa),flexural strength(84.21 MPa)and modulus(5.81 GPa),and impact strength(5.39 kJ/m2)when compared with the PALF/PF and KF/PF composites.Scanning electron microscopy(SEM)was used to observe the fracture surfaces of the tensile testing samples.The microstructure of the 7P3K hybrid composite showed good interfacial bonding and the addition of KF improved the interfacial strength.It has been concluded that the 3P7K ratio allowed obtaining materials with better mechanical properties(tensile,flexural and impact strengths)than PALF/PF and KF/PF composites.The results obtained in this study will be used for further comparative study of untreated hybrid composites with treated hybrid composites.

Influence of Non-smooth Surface on Tribological Properties of Glass Fiber-epoxy Resin Composite Sliding against Stainless Steel under Natural Seawater Lubrication

With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawater lubrication are still very fewer, especially experimental research. The influences of smooth and non-smooth surface on the frictional properties of the glass fiber-epoxy resin composite（GF/EPR） coupled with stainless steel 316 L are investigated under natural seawater lubrication in this paper. The tested non-smooth surfaces include the surfaces with semi-spherical pits, the conical pits, the cone-cylinder combined pits, the cylindrical pits and through holes. The friction and wear tests are performed using a ring-on-disc test rig under 60 N load and 1000 r/min rotational speed. The tests results show that GF/EPR with bionic non-smooth surface has quite lower friction coefficient and better wear resistance than GF/EPR with smooth surface without pits. The average friction coefficient of GF/EPR with semi-spherical pits is 0.088, which shows the largest reduction is approximately 63.18% of GF/EPR with smooth surface. In addition, the wear debris on the worn surfaces of GF/EPR are observed by a confocal scanning laser microscope. It is shown that the primary wear mechanism is the abrasive wear. The research results provide some design parameters for non-smooth surface, and the experiment results can serve as a beneficial supplement to non-smooth surface study.

Experimental Study on Influence of Dimples on Lubrication Performance of Glass Fiber-epoxy Resin Composite under Natural Seawater Lubrication

Bionic non-smooth surface is widely applied in metal and ceramics materials. In order to introduce this technology to high pressure seawater pump, the influence of bionic non-smooth surface on the engineering plastics used in pump should be investigated. The comparative tests are carried out with a ring-on-disc configuration under 800, 1000, 1200 and 1400 r/min in order to research the influence of the bionic non-smooth surface on glass fiber-epoxy resin composite（GF/EPR） under natural seawater lubrication. The disc surfaces are textured with five kinds of pits, which are semi-spherical, conical, cone-cylinder combined, cylindrical pits and through holes, respectively. A smooth surface is tested as reference. The results show that the lubrication performance of dimpled GF/EPR sample is much better than that of the smooth sample under all rotational speeds. The semi-spherical pits surface has more obvious friction reduction than the others, which shows that the least reduction is approximately 43.29% of smooth surface under 1200 r/rain. However, the wear level is only marginally influenced by dimples. The surface morphology investigations disclose severe modifications caused by abrasive wear primarily. The results are helpful to vary friction properties of GF/EPR by non-smooth surface, or provide references to the design of non-smooth surfaces under certain condition.

Mechanical Properties of Glass Fiber/Unsaturated Polyester Resin Composite Water Collector

The water collector is operated in the humid and hot environment of the cooling tower all the year round.It also needs to carry part of the weight of water and silt.Therefore,it is particularly critical to optimize the material of the water collector and improve its mechanical properties.Polyester,a general term of polymer obtained from polyols and polyacids,is a kind of engineering plastics with excellent properties and wide applications.Glass fiber is a reinforced plastic reinforcement material,and the biggest characteristic of it is the high tensile strength and good heat resistance.In this paper,glass fiber reinforced polyester resin composite material is prepared,its tensile properties and bending properties are tested,and the performance of the imported material JK2020B is compared and analyzed.The results show that the elastic modulus along the fiber direction is relatively high,but the interlayer force in the direction of thickness and width is very small.This review provides a guidance for production process.

Fabrication and Characterization of Glass Fiber with SiC Reinforced Polymer Composites

Glass Fiber Reinforced Polymeric (GFRP) Composites are most commonly used as bumpers for vehicles, electrical equipment panels, and medical devices enclosures. These materials are also widely used for structural applications in aerospace, automotive, and in providing alternatives to traditional metallic materials. The paper fabricated epoxy and polyester resin composites by using silicon carbide in various proportions along with GFRP. The hand lay-up technique was used to fabricate the laminates. To determine the properties of fabricated composites, the tensile, impact, and flexural tests were conducted. This method of fabrication was very simple and cost-effective. Their mechanical properties like yield strength, yield strain, Young’s modulus, flexural modulus, and impact energy were investigated. The mechanical properties of the GFRP composites were also compared with the fiber volume fraction. The fiber volume fraction plays a major role in the mechanical properties of GFRP composites. Young’s modulus and tensile strength of fabricated composites were modelled and compared with measured values. The results show that composites with epoxy resin demonstrate higher strength and modulus compared to composites with polyester resin.

Effect of Natural Fiber Reinforced Polypropylene Composite Using Resin Impregnation

In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injection molded composites was investigated by carrying out tensile and banding tests, followed by Scanning electron microscopy (SEM) observation of fiber surface and fracture surface of composites. The tensile strength of natural fiber and natural fiber reinforced composites with resin impregnation method increases with Polyvinyl alcohol (PVA) impregnation. In addition, Phenol resin impregnation recovers fiber tensile strength after alkali treatment. Resin impregnation causes decrease in contact surface area;however, it does not cause decrease in mechanical properties. Our results suggest that the using rein impregnation method has better effect on the mechanical properties of natural fiber reinforced Polypropylene (PP) composites.

Effect of Silane Coupling Agent on the Flexural Property of Glass Fiber Reinforced Composite Film

Transparent glass fiber reinforced composites films ware fabricated by UV light induced chemical crosslinking of composite materials consisting of glass fiber and UV curable resin in film state. In order to apply film to flexible device, excellent flexural property is required, then the delamination should not occurred between glass fiber and UV curable resin when film is bent. To minimize delamination and improve the interfacial adhesion at interface between glass fiber and UV curable resin, the γ-aminopropyl triethoxy silane and γ-glycid oxypropyl trimethoxy silane were applied for the surface treatment of glass fibers. Silanization of glass fiber surface was checked by scanning electron microscopy and the degree of delamination of composite film was confirmed through the bending test, ASTEM290-96a, used by haze meter.

Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

Study of Maleic Anhydride Grafted Polypropylene Effect on Resin Impregnated Bamboo Fiber Polypropylene Composit

Previously, Polyvinyl Alcohol (PVA) and phenolic resin were used for resin impregnated bamboo fiber reinforced PP composites which was manufactures for resin impregnated bamboo fiber with polypropylene (PP). Resin impregnation method can show improvement on tensile strength of fiber. However, to reduce the contact surface area and low inter-facial shear strength (IFSS) between impregnated resin and matrix, using 40% weight fraction of bamboo fiber in PP matrix, PVA impregnated composites with mean flexural and tensile strength 10% higher than untreated composites were produced butphenolic resin impregnated fiber reinforced composition’s mechanical properties were decreased. In this study maleic anhydride grafted polypropylene (MAPP) was used to increase interfacial shear strength between resin impregnated fiber and PP. With 10% MAPP, IFSS between resin impregnated fiber and PP increased more than 100% and reinforced composites. MAPP with untreated, phenolic resin and PVA impregnated cases showed similar mechanical properties. Yet in water absorption test, the PVA treatment with bamboo/PP composites increased water absorption ratio. But with 10% MAPP, matrix PP water absorption ratio decreased like phenolic resin impregnated fiber reinforced composites. 10% MAPP with resin impregnated bamboo fiber reinforced PP composites can improve IFSS, mechanical properties of composite and can decrease water absorption PVA resin impregnated bamboo fiber reinforced composites.

Mechanical Properties of Submicron Glass Fiber Reinforced Vinyl Ester Composite

Vinyl ester (VE) resin inherently has intrinsic brittleness due to its high cross-link density. To improve mechanical performance, micro/nano fillers are widely used to modify this matrix. In present study, glass fiber in submicron scale at low contents was added into VE to prepare submicron composite (sMC). The impact resistance of un-notched sMC degraded with the increase of sGF content while that of notched-sMC remained the unchanged. Flexural properties of sMCs also were the same with that of neat resin. The results of Dynamic mechanical analysis (DMA) test showed the slight increase of storage modulus and the decrease of tan delta value in the case of sMC compared to those of un-filled matrix. However, the Mode I fracture toughness of sMC improved up to 26% and 61% corresponding to 0.3 and 0.6 wt% glass fiber used. The compact tension sample test suggests that there is the delay of crack propagation under tensile cyclic load in resin reinforced by submicron glass fiber. The number of failure cycle enlarged proportionally with the increment of sGF content in matrix.

Effect of Filler Content on Flexural and Viscoelastic Properties of Coir Fibers and Argania Nut-shells Reinforced Phenolic Resin Composites

The characteristics of two different kinds of lignocellulosic materials(vegetable fillers)with two morphologies as Argania nut-shells(ANS)particles and Coir Fibers(CF)were used as reinforcement for phenolic resin(Bakelite)in this work,and the composite are studied as a function of filler types,shape,content(10,20,and 30%wt.percent)and manufacturing loading force(1500 and 3000 LBs).Compression molding was used to create the composites,which were then evaluated using Scanning electronic microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR),bending,dynamic-mechanical-thermal and rheological studies.The morphology of broken samples demonstrates that both fillers are well dispersed and distributed.When fillers are added to the matrix,the flexural characteristics improve,and the optimal values are attained in the case of Argania nut-shells.The results showed that the kind and shape of the fillers had a direct influence on the dynamic mechanical characteristics of the composites due to the reinforcement's modulus augmentation.It was noticed that,the increment of manufacturing loading force decreased the mechanical and dynamical properties of composites.The optimum properties obtained indicate that the composites can only be manufactured at low manufacturing loading force(1500 LBs).

热塑性复合材料玻璃纤维环氧成膜剂的制备与性能研究

本文采用化学改性法,以环氧氯丙烷、共聚物P105、环氧树脂E-51和双酚A为原料,制备了一种水性环氧树脂乳液作为玻璃纤维成膜剂,研究了原料摩尔比、E-P105用量和乳化温度对乳液粒径和稳定性的影响。结果表明,当P105、ECH、NaOH摩尔比为1∶1.5∶1.2,环氧树脂与双酚A摩尔比为2.25∶1,E-P105质量份数为环氧树脂和双酚A质量的20%,乳化温度为60℃时,乳液粒径为0.387μm,粒径分布均匀,具有良好的稳定性,经上浆处理后的玻璃纤维复合材料力学性能优异。

防热复合材料湿热老化行为与贮存寿命研究

目的研究装备用防热复合材料在贮存条件下的性能变化规律和寿命评估。方法在90℃/90%RH、80℃/90%RH、70℃/90%RH和80℃/80%RH共4个试验条件下,对玻璃纤维增强酚醛树脂防热复合材料开展加速湿热老化试验,借助红外光谱分析、扫描电镜、导热系数和力学性能测试研究老化过程中材料的质量、导热系数、力学性能、化学组分、微观形貌的变化规律,使用Peck模型对材料的贮存寿命进行计算。结果材料在老化初期吸湿后,质量快速增加,吸湿趋于饱和后,质量达到最大值。随着老化时间的延长,材料的质量呈缓慢下降趋势。不同湿热条件下,材料的导热系数未出现性能退化现象,材料的拉伸强度均出现退化现象,老化温度越高,性能下降越明显。在90℃/90%RH条件下,老化时间为80d时,材料强度大约下降到初始性能的53.4%。湿热老化过程中,红外光谱中960cm^(‒1)处特征峰逐渐减弱,直至完全消失,1098cm^(‒1)处特征峰相对强度逐渐变强。湿热老化后,材料部分玻璃纤维与基体间界面有微裂纹产生,拉伸断裂后,大部分纤维从树脂基体中拔出,表面平整光滑,黏连树脂较少。结论防热复合材料的老化是由氧化反应的化学老化与湿热条件导致界面脱黏、基体开裂、微裂纹等物理老化综合作用的结果。防热复合材料在20℃/60%RH条件的贮存寿命为36.3a,满足实际构件的设计寿命。

玻纤增强环氧树脂力学与耐老化性能研究

采用偶联剂KH560对短切玻璃纤维(玻纤)进行改性,并以改性短切玻纤作为增强材料制备得到玻纤/环氧树脂复合材料。随着玻纤质量分数的增加,材料的拉伸、弯曲和冲击强度均呈现先增大后减小的趋势。当玻纤填充质量分数为10%时,材料的力学增强、增韧效果达到最佳。SEM表征表明玻纤与树脂基体界面结合良好,可以有效传递树脂与玻纤间的应力,且玻纤的介入也可有效阻挡裂纹的扩展,起到增强、增韧作用。然而当玻纤质量分数过高时,由于材料的分散性变差,其力学性能下降。复合材料经短时间的紫外老化后,因紫外光氧作用颜色发生很大变化,然而由于玻纤具有很好的化学稳定性,可以延缓紫外氧化损伤进一步深入到材料内部,材料的外观颜色变化开始放缓。在水分作用下,树脂也会发生一定的水解。这些破坏使材料的力学性能随着老化时间的延长不断降低。上述研究可为后续开发用于替代金属电力金具的性能更优越的玻纤增强环氧树脂提供理论基础。

石墨烯/酚醛复合纤维的制备及性能

石墨烯纤维是新一代柔性器件的潜力电极材料,制备同时具有良好力学性能和电化学性能的石墨烯基复合纤维是研究的重点。以改良的Hummers法制备的氧化石墨烯为基体,酚醛树脂为增强体,冰乙酸为凝固浴,通过非液晶湿法纺丝的方法制备了石墨烯/酚醛复合纤维,并对得到的石墨烯/酚醛复合纤维的表面形貌、力学性能和电化学性能进行了研究。结果表明,酚醛树脂通过氢键与石墨烯片层相结合,从而减少石墨烯片层间的堆叠,使复合纤维的表面褶皱丰富且均匀。通过调控酚醛树脂的含量,可以得到具有不同表面褶皱程度的复合纤维。随着酚醛树脂用量的增加,纺丝液浓度增大,挤出胀大现象明显,复合纤维片层间隙增大,表面沟壑加深,缺陷增加。石墨烯/酚醛复合纤维的拉伸强度随着酚醛树脂用量的增加呈现先增大后减小的趋势,酚醛树脂用量为10%时纤维的拉伸强度和拉伸弹性模量分别为65.53 MPa和672.91 MPa。得益于表面丰富均匀的褶皱,在电流密度为0.2 A/cm^(3)时,氧化石墨烯∶酚醛为100∶10时体积比电容为583.4 F/cm^(3),远高于纯石墨烯纤维。

碳纤维/酚醛树脂复合材料热解特性研究

使用热重-差热同步分析仪研究了某飞机框架部位用碳纤维/酚醛树脂复合材料在不同气氛和不同升温速率条件下的热分解特性。结果表明:在空气气氛下碳纤维/酚醛树脂复合材料热解反应分为3个阶段,在氮气气氛下热解反应分为2个阶段;随着升温速率的提高,氮气气氛下复合材料热解的初始分解温度、第2阶段起始温度都随着升温速率的提高而增加,2个阶段的热解温度范围都逐渐变宽且每一阶段的温度范围都要高于前一个热解阶段,最大失重速率温度也向高温方向移动,相同温度下失重明显变大。采用Kissnger法、FWO法、Starink法对碳纤维/酚醛树脂复合材料的热解动力学进行计算,得到其表观活化能。

玻璃纤维增强环氧树脂表面电痕化显微特征影响分析

为探究玻璃纤维增强环氧树脂复合绝缘材料的表面放电过程及其显微特征,本文通过搭建斜板电极实验平台,采用恒定电痕化电压法对试样进行表面电痕化和蚀损试验,并结合理想液体的伯努利方程分析了电痕的形成机理。还测试了不同电痕蚀损阶段下环氧树脂材料的官能团变化情况、表面粗糙度以及三维形貌。结果表明:绝缘复合材料的潮湿污秽区域极易产生泄漏电流并发生放电,且电痕放电和最严重的损蚀情况总是首先出现在下电极处;随着试样表面电痕腐蚀程度增加,环氧树脂分子链中环氧基、羟基、氨基、醛基逐渐分解,羰基产生后又不完全分解;材料的表面形貌逐渐变得粗糙和不规则,表面粗糙度呈上升趋势,其中爆发期的粗糙度约为起始期的2.8倍。

湿热环境对环氧树脂基复合材料拉伸性能的影响

采用加速吸湿法得到玻璃纤维/L285环氧树脂基复合材料吸湿特性曲线,通过对比分析湿热处理前后的化学结构、断口微观形貌以及力学性能,研究了湿热环境对玻璃化转变温度、损伤机理、抗拉强度以及弹性模量的影响,探究湿热老化机制,为通用航空飞机的安全运行提供理论和实验依据。结果表明,该复合材料吸湿初期符合Fick第二定律,后期吸湿曲线逐渐趋于平缓,湿度一定时,温度越高,吸湿率越大,达到吸湿饱和时间越长。水浴温度由25 ℃增加到85 ℃时,饱和吸湿率增加209%,相应吸湿饱和时间增加46.50%;湿热处理后复合材料的拉伸断裂失效形式发生改变,抗拉强度降低30.97%,弹性模量在6%范围内波动,加载初期应力—应变曲线呈线性关系,后期呈非线性变化趋势;相对25 ℃干态试样,85 ℃湿态试样的玻璃化转变温度下降24 ℃,相应的化学结构未发生变化,但纤维-基体界面发生了不可逆的物理变化。

玻璃纤维/环氧树脂复合材料燃烧特性研究

采用锥形量热仪、垂直水平燃烧试验仪、极限氧指数测试仪等手段研究玻璃纤维/环氧树脂复合材料在不同火灾环境下的燃烧特性。结果表明:随热辐射强度的增加,实验样品的平均点燃时间逐渐缩短,热释放速率和热释放速率峰值均增大,峰值出现时间提前,燃烧后残余率降低。由于玻璃纤维的抑制作用,复合材料总体质量损失幅度较小。实验样品在水平燃烧试验中未能点燃,在垂直燃烧试验中,平均烧焦长度48.3mm,移去火源后的平均焰燃时间为11.8s。氧指数试验显示,温度升高200℃后,其值降为室温氧指数的74.9%,表明在高温环境下复合材料更易被点燃。玻璃纤维的存在能够抑制环氧树脂的热解和燃烧。