Effect of Atmospheric Plasma Treatment on Carbon Fiber/Epoxy Interfacial Adhesion

In this work the effect of atmospheric plasma treatment on carbon fiber has been studied. The carbon fibers were treated for 1, 3 and 5 min with a He/O₂ dielectric barrier discharge atmospheric pressure plasma. The fiber surface morphology, surface chemical composition and interfacial shear strength between the carbon fiber and epoxy resin were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and the single fiber composite fragmentation test. Compared to untreated carbon fibers, the plasma treated fiber surfaces exhibited surface morphological and surface composition changes. The fiber surfaces were found to be roughened, the oxygen content on the fiber surfaces increased, and the interfacial shear strength (IFSS) improved after the atmospheric pressure plasma treatment. The fiber strength showed no significant changes after the plasma treatment.     

碳纳米管/聚合物复合吸波材料性能研究

碳纳米管通过化学气相沉积工艺制备,碳纳米管直径10～30nm,纯度>90%。碳源为乙炔、铁/镍复合催化剂。加入适量的有机溶剂丙酮溶解环氧树脂,然后加入碳纳米管。分别高速搅拌和超声处理30min,加入固化剂乙二胺搅拌均匀,超声10min除去气体后,浇铸在铝板上制成吸波涂层。TEM检测碳纳米管。反射率扫频测量系统HP8757E标量网络分析仪检测吸波性能。碳纳米管和环氧树脂比例为1∶100时,3mm厚吸波层试样吸波峰出现在14 32GHz,吸波峰值R=-10 01dB,吸波频带宽度为2 16GHz(R<8dB)。厚度增加到9mm,在11GHz和17 83GHz出现双吸波峰,最大吸波峰出现在17 83GHz峰值R=-9 04dB,带宽约1GHz(R<8dB)。比例调整为5∶100时,波峰出现在7 91GHz,峰值加大到R=-13 89dB,带宽度达到3 19GHz(R<8dB)。     

纳米TiO2对环氧树脂及碳纤维增强复合材料力学性能的影响

利用超声波技术将纳米TiO2在环氧树脂中进行分散,考察了纳米TiO2含量对环氧树脂及碳纤维/环氧复合材料力学性能的影响。研究表明,纳米TiO2可对环氧树脂固化物同时起到增韧增强的作用,冲击断口形貌显示为典型的韧性断裂。同时纳米粒子的加入可改善碳纤维和树脂基体的界面粘结性能,提高复合材料的层间剪切强度。     

Plasma Modified Polyaramid Fiber Surface and Fiber/Epoxy Interface

Kevlar-49^® was surface-modified through cold air plasma treatment and plasma grafting of poly-acrylic-acid (PAA), polyethylacrylate (PEA) and their copolymer (PAA/EA). To evaluate the effect of modification, the single fiber pull out (SPFO) test was developed; at least three important physical quantities, G _i , F _r L and τ_o were obtained. For grafting with PAA/EA, G _i increased to 55 J/m² in comparision with 36 J/m² for Kevlar fibers with the sizing removed. The surface topography of fibers pulled from epoxy resin was studied by scanning electron microscopy (SEM).     

多壁碳纳米管在国产碳纤维增强环氧树脂复合材料中应用

研究了一种简易有效的多壁碳纳米管(MWNTs)分散入环氧树脂的方法,对树脂的工艺性进行试验研究;使用碳纤维复丝的力学性能来表征纤维/树脂界面性能和纤维强度转化效果,制备了含MWNTs的环氧树脂/碳纤维预浸料,并对使用此预浸料制备的复合材料单向板进行力学性能测试。结果表明,当MWNTs的用量为E–51的0.5%时,二者混合球磨8 h后配制的树脂溶液适用期大于24 h,黏度小于0.8 Pa·s,树脂浇铸体拉伸强度78 MPa,弯曲强度106 MPa,断裂伸长率4.3%;添加MWNTs之后纤维/树脂结合良好,复合材料单向板拉伸强度提升了7.2%,弯曲强度提升了9.73%,压缩强度提升了6.82%,层剪强度提升了11.54%。     

树脂含量对碳布/环氧复合材料力学性能的影响

主要研究了不同树脂含量下，碳布／环氧复合材料的径向拉伸和纬向压缩性能，并初步探讨了树脂含量对复合材料拉伸、压缩性能的影响机理。试验结果表明：树脂含量对复合材料力学性能的影响较大，当树脂质量含量在42％－45％之间时，拉伸、压缩性能较好。     

The Effect of Low Power Nitrogen Plasma Treatment of Carbon Fibres on the Interfacial Shear Strength of Carbon Fibre/Epoxy Composites

Type II (high strength) carbon fibres have been given a low power nitrogen plasma treatment. It is shown that this plasma treatment has no effect on the fibre diameter, no detrimental effect on fibre strength and can significantly improve fibre/resin adhesion. It is proposed that this improvement is due to chemical interaction via amine/epoxy bonding at the edge sites together with the interaction of the epoxy with activated basal planes present on the fibre surface. This improvement is only achieved if the fibres are immersed in resin before being exposed to air. Exposing the treated fibres to air drastically reduces fibre/adhesion due to the adsorption of moisture from the environment. Heating these latter fibres in a vacuum at 130°C for one hour allows some recovery of the interfacial strength. It is also demonstrated that the interfacial shear strength falls dramatically when the nitrogen-containing functional groups are completely removed from the fibre surface.     

The Effect of Low Power Nitrogen Plasma Treatment of Carbon Fibres on the Interfacial Shear Strength of Carbon Fibre/Epoxy Composites

Type II (high strength) carbon fibres have been given a low power nitrogen plasma treatment. It is shown that this plasma treatment has no effect on the fibre diameter, no detrimental effect on fibre strength and can significantly improve fibre/resin adhesion. It is proposed that this improvement is due to chemical interaction via amine/epoxy bonding at the edge sites together with the interaction of the epoxy with activated basal planes present on the fibre surface. This improvement is only achieved if the fibres are immersed in resin before being exposed to air. Exposing the treated fibres to air drastically reduces fibre/adhesion due to the adsorption of moisture from the environment. Heating these latter fibres in a vacuum at 130°C for one hour allows some recovery of the interfacial strength. It is also demonstrated that the interfacial shear strength falls dramatically when the nitrogen-containing functional groups are completely removed from the fibre surface.     

YSZ涂覆碳纤维/环氧复合材料性能的研究

采用溶胶-凝胶法在碳纤维的表面涂覆了一层钇稳定氧化锆(YSZ)涂层，并研究了用其制备的碳纤维／环氧复合材料的性能。结果表明：涂层中粒子的粒经约为10nm，YSZ涂覆后复合材料的层间剪切强度(ILSS)、拉伸强度和弯曲强度分别提高了52．0％、6．5％和6．3％；YSZ涂覆后的碳纤维与环氧树脂基体的结合更加紧密，且在碳纤维表面形成的YSZ涂层在450～700℃能有效地减缓碳纤维／环氧复合材料的氧化失重速率。     

快速固化环氧树脂/碳纤维复合材料的性能

利用差示扫描量热分析仪研究了一种快速固化环氧树脂体系的固化工艺参数,确定了以真空辅助树脂灌注工艺制备快速固化环氧树脂/碳纤维复合材料的成型方法,并与常规固化环氧树脂体系制备的碳纤维复合材料进行对比,采用傅里叶变换红外光谱仪对两种材料的树脂基体进行了分析,考察了两种复合材料的纤维含量、孔隙率及力学性能,最后通过扫描电子显微镜观察了快速固化树脂基体与碳纤维的界面结合性。结果表明,快速固化树脂在99℃下固化6 min后固化度可达96%,能够大幅缩减碳纤维复合材料的成型时间,以其制备的碳纤维复合材料拉伸强度比常规固化环氧树脂复合材料高11.20%,弯曲强度高16.92%,纵横剪切强度高7.44%,快速固化树脂与碳纤维界面结合性良好。     

碳纤维布表面处理对酚醛树脂复合材料力学性能的影响

以碳纤维布(CB)为增强相,丁苯橡胶为增韧剂,酚醛树脂(PF)为基体,通过模压成型工艺制得了PF/CB复合材料,研究了CB表面处理方式、丁苯橡胶含量及加工成型温度对PF/CB复合材料的界面结合及力学性能的影响。结果表明,丙酮处理CB、氧化处理CB及加工成型温度的提高都能改善纤维与基体的结合程度,提高界面结合力。但氧化处理CB随着加工成型温度的提高,易断裂,对复合材料的增强作用有所减弱。丁苯橡胶加入量为12%时PF的加工及冲击性能为最佳。     

等离子体处理对芳纶性能的影响

芳纶作为增强材料在复合材料中有广泛的应用,其界面性能是影响其复合材料界面粘结性能的重要因素。分别采用H2、空气低温等离子体对芳纶表面进行了处理。研究了等离子体表面改性后芳纶性能的变化。结果表明:经低温等离子体处理后纤维表面张力增大,由46.0mN·m-1增加到63.2mN·m-1;表面极性增强,极性分数由58.0%提高到69.9%,而纤维单丝断裂强度未有明显变化。     

环氧树脂/碳纤维/BN导热复合材料制备及研究

采用高温模压成型法制备环氧树脂/碳纤/BN导热复合材料.探讨了BN用量对复合材料导热性能和力学性能的影响.结果表明,当BN用量为6%(wt)时,复合材料的弯曲强度和剪切强度较佳,BN用量对复合材料的冲击强度影响不大;导热性能随BN用量的增加而增加,当BN用量为20%(wt)时,导热系数为0.8438W/m·K.     

热熔膜法碳纤维/环氧树脂预浸料制备工艺

采用自制的环氧树脂膜与碳纤维一起热压制备预浸料,并通过正交试验设计改变热压温度、时间和压力这三个工艺参数来探讨制备预浸料时热压工艺参数对预浸效果的影响,制成的预浸料固化成复合材料后测定其力学性能,以此来确定预浸料的最优热压工艺参数。测得制备的预浸料挥发分质量分数为(0.6±0.1)%、树脂质量分数为(55±2)%。正交试验结果表明:当热压温度为60℃,时间为50 s,压力为1.5 MPa时,复合材料的拉伸强度最高。     

表面处理对环氧树脂/PBO纤维界面剪切强度的影响

采用了磺化聚芳酰胺(SPA)和固化剂593分别对PBO纤维进行表面处理,用钢针将配好的环氧树脂基体溶液似微球状滴在固定在试样架上的PBO纤维上,考察了处理前后PBO纤维与环氧树脂界面剪切强度的变化。结果表明,两种表面处理对PBO纤维与环氧树脂基体的界面剪切强度都有贡献,其中固化剂处理能显著提高界面剪切强度,改变了界面破坏模式,使PBO纤维与环氧树脂基体的界面剪切强度最高可达19.41 MPa,比未处理时的界面剪切强度提高95%。     

Plasma Modifications to the Interface in Carbon Fiber Reinforced Thermoplastic Matrices

Radio frequency glow discharge oxygen plasma was used to modify the surfaces of PAN-based and mesophase pitch-based carbon fibers. Surface chemical changes to the fibers were monitored by X-ray photoelectron spectroscopy and by fiber wetting studies evaluated in terms of dispersive-polar components of surface energy and acid-base contribution to the work of adhesion. Physical changes to these fibers were monitored by scanning electron microscopy. Stress transferability of these fibers was evaluated by the embedded single fiber test in poly(methyl methacrylate), poly(ethyl methacrylate), poly(methacrylonitrile) and poly(vinyl chloride) as these matrices offered varying degrees of dispersive-polar and acid-base character. Experimentally determined critical aspect ratios were compared to the theoretical work of adhesion determined by dispersive-polar interactions and with the Lewis acid-base nature of the matrices.     

Plasma Modifications to the Interface in Carbon Fiber Reinforced Thermoplastic Matrices

Radio frequency glow discharge oxygen plasma was used to modify the surfaces of PAN-based and mesophase pitch-based carbon fibers. Surface chemical changes to the fibers were monitored by X-ray photoelectron spectroscopy and by fiber wetting studies evaluated in terms of dispersive-polar components of surface energy and acid-base contribution to the work of adhesion. Physical changes to these fibers were monitored by scanning electron microscopy. Stress transferability of these fibers was evaluated by the embedded single fiber test in poly(methyl methacrylate), poly(ethyl methacrylate), poly(methacrylonitrile) and poly(vinyl chloride) as these matrices offered varying degrees of dispersive-polar and acid-base character. Experimentally determined critical aspect ratios were compared to the theoretical work of adhesion determined by dispersive-polar interactions and with the Lewis acid-base nature of the matrices.     

紫外老化对芳纶／环氧复合材料性能和结构的影响

通过紫外老化试验（温度（40±5）℃,湿度40％）,研究了芳纶、环氧及其复合材料的力学性能、玻璃化转变温度、失重随老化时间的变化,并用红外光谱分析了芳纶的结构变化。结果表明：经紫外老化后,芳纶／环氧的拉伸强度、失重率有明显的变化,芳纶结构和复合材料的玻璃化转变温度无明显的变化。     

Effect of Resin:Fiber Ratio on the Properties of Glass Fiber Reinforced Plastic Composites

ABSTRACT

Studies on the effect of resin:fiber ratios on the properties of GFRPs were carried out. The GFRPS laminated composites were prepared by hand lay-up technique. Five types of resin:fiber ratios were studied such as 4:1, 3:1, 2:1, 1.5:1, and 1:1. The correlation of the resin:fiber ratio with the end physical and flexural properties was analyzed. In the present studies, the effect of water absorption on the flexural properties of GFRPs laminates was examined. As a result, it was found that the properties of GFRPs are governed by the resin:fiber ratio, which further influences the properties of GFRP before and after water absorption test.