自行车架用碳纤维与环氧树脂浸润性研究

采用三种RTM工艺成型的环氧树脂体系分别对碳纤维进行浸润,并制备了自行车架用碳纤维复合材料。采用自制浸润度观察仪,粘度、表面张力和力学性能测试以及红外光谱和扫描电镜分析研究了不同环氧体系对碳纤维的浸润性。结果表明:粘度低的AF-802环氧树脂体系对碳纤维的浸润性最佳,最大浸润高度为28.41 mm;环氧树脂体系对含上浆剂碳纤维的浸润性能优于无上浆剂的碳纤维。浸润性改进有益于碳纤维复合材料弯曲强度提高,发挥碳纤维车架的整体效能,提高整车安全性。     

酚醛树脂对玻璃纤维的浸润性研究

为研究酚醛树脂对玻纤的浸润性能,更好地指导实际生产,考察了两种酚醛树脂和三种玻璃纤维。通过添加稀释剂和分散剂改变树脂体系的表面张力、粘度和树脂对玻纤的动态接触角,采用靶环试验测试了多种树脂体系对三种玻纤的浸润速率,筛选出浸润性能最好的树脂体系和玻璃纤维。研究表明,表面张力越低,粘度越小,树脂与玻纤的动态接触角越小,越有利于提高树脂对玻纤的浸润效果。     

T700级炭纤维表面特性及其对复合材料界面性能的影响

以不同厂家生产的3种T700级炭纤维T700SC、UT500和CFT700为研究对象,采用SEM、AFM对纤维的表面形貌和粗糙度进行表征,通过表面/界面张力仪对炭纤维的表面能和浸润性能进行分析,然后对炭纤维/环氧618复合材料的层间剪切强度和断面形貌进行分析,以探讨炭纤维表面特性和浸润性能与复合材料界面性能的关联。结果表明,T700SC纤维表面光滑,粗糙度较小,UT500和CFT700纤维呈现表面沟槽状态,粗糙度较大。与T700SC纤维相比,UT500和CFT700纤维表面能更高,与环氧树脂具有更好的浸润性能。ILSS测试和断面分析结果表明,T700SC纤维复合材料ILSS为67.34 MPa,界面结合较差;UT500和CFT700复合材料ILSS分别为79.54 MPa和85.69 MPa,界面结合较好。炭纤维浸润性能与复合材料的宏观ILSS性能具有较好的一致性。     

碳纤维表面性能对界面黏结强度的影响浅析

为了解碳纤维表面性能对纤维-树脂界面黏结强度的影响,使用扫描电镜、原子力显微镜与X射线光电子能谱仪(XPS),对国产T-300级碳纤维、台丽TC36S碳纤维、东丽T700S碳纤维的表面进行物理与化学表征,得出:国产碳纤维与TC36S碳纤维表面形貌相近,而T700S表面比较光滑;XPS定量分析技术表明3种碳纤维表面的活性差异较大,碳纤维与树脂的界面黏结强度随纤维粗糙度和表面活性官能团而变化。     

制样基体树脂及固化张力对碳纤维复丝拉伸性能的影响

针对碳纤维复丝拉伸性能测试的制样过程,通过采用不同基体树脂、施加不同丝束固化张力进行T300B、T700SC及T800H三种碳纤维复丝拉伸性能测试值影响因素研究。结果表明:碳纤维复丝拉伸性能的测试值与基体树脂的黏度相关不明显,而与基体树脂的断裂伸长率密切相关,在基体树脂断裂伸长率不超过测试纤维4倍的条件下,基体树脂的断裂伸长率越高,越有利于保证碳纤维复丝力学性能的测试值准确;适当增加碳纤维复丝制样过程中的纤维固化张力,能提高碳纤维复丝力学性能的测试值,碳纤维丝束越大,需要的固化张力越高。     

碳纤维/环氧界面相准静态纳米压痕表征方法分析

界面相作为纤维与树脂之间载荷传递的桥梁,其性质对整体复合材料力学性能和耐环境性能有直接影响。本研究用准静态纳米压痕技术对碳纤维T300/环氧E51体系的界面相模量进行测试分析。研究发现,当探针压入深度大于30nm以后,试样表面粗糙度对测试结果的影响可以忽略;同时,三种测试排点方式下的纳米压痕结果表明:纤维增强效应对载荷-压深曲线影响很大,由于压深和压痕间距较大,对于界面相宽度较小的碳纤维环氧复合材料体系,采用准静态纳米压痕技术不易得到其界面相的模量。     

基于Wilhelmy法的单一炭纤维/环氧树脂动态接触角测量及表面能表征

基于Wilhelmy法对日本东丽T700炭纤维/BA202环氧树脂体系动态接触角的测量方法进行研究,利用测试得到的"润湿回线"分析探讨炭纤维与树脂间的浸润过程,并基于此"润湿回线"进行测试条件优化,得到最佳测试条件为纤维伸出测量夹具4 mm、纤维浸入树脂深度2 mm、检测速度1 mm/min、检测阈值0.0002 g和炭纤维单丝根数6根。最后通过测试炭纤维上浆前后与树脂的接触角变化及计算对应的纤维表面能及其组成的变化,得出该表面上浆剂能够提高T700炭纤维的表面能,降低纤维接触角,增强纤维与基体树脂间的结合力,提高其浸润性能的结论。     

碳纤维湿法缠绕用高模量高韧性环氧树脂基体

设计了一系列针对碳纤维湿法缠绕的环氧树脂基体,测试了树脂浇注体及其复合材料的力学性能和热机械性能,研究了树脂基体对碳纤维复合材料界面性能的影响.试验结果表明,对韧性树脂体系,树脂基体的模量是发挥纤维强度的关键因素,模量的提升将大幅提高复合材料的综合性能.经复配和优化的树脂体系兼具高模量和高韧性,其T700碳纤维复合材料NOL环拉伸强度达到2480MPa,T800碳纤维复合材料NOL环拉伸强度达到2780MPa,玻璃化温度(Tg)超过200℃,具有优异的界面性能和耐热性能.     

纤维缠绕用改性氰酸酯树脂体系研究

本文采用环氧树脂对氰酸酯树脂进行改性,研究出适合纤维湿法缠绕的改性氰酸酯体系.通过凝胶实验和DSC等方法研究了改性树脂体系的固化性能,以及改性树脂体系粘度随温度和时间的变化趋势,从而确定其纤维缠绕工艺温度、速度等参数及树脂体系的使用期.对改性树脂基体的热性能、介电性能、力学性能以及改性树脂基体与玻璃纤维、碳纤维的界面性能进行了研究.     

碳纤维/TDE85环氧树脂复合材料界面性能的研究

高性能碳纤维增强树脂基复合材料因其轻质、高强、高模量等优势,已在航空航天等领域广泛应用,增强体与树脂基体之间的界面结合状况对其性能有很大影响,因此对界面进行研究具有非常重要的意义。本文分别研究了T800、CCF300、T300三种碳纤维增强TDE85环氧树脂复合材料的界面性能。运用XPS对碳纤维和单纤维复合材料试样的表面化学成分进行了表征,XPS结果表明,与树脂复合后,碳纤维表面官能团的含量、结构及化学环境都发生了明显的变化,界面产生了较强的物理和化学作用。利用DCT21测量仪测试碳纤维与环氧树脂TDE85的接触角,分析了纤维与树脂的润湿性,实验结果显示纤维与树脂的润湿性良好。在此基础上,通过微滴脱粘方法测量纤维与树脂的界面剪切强度,以表征其界面粘结性能。微滴脱粘的实验结果显示,T800/TDE85体系的IFSS值高达79.7MPa,比T300/TDE85、CCF30/TDE850体系分别高21%、24%。     

Effect of ultrasound on wettability between aramid fibers and epoxy resin

Good wetting of reinforced fiber by resin was a main factor in the improvement of the interface adhesion of their composites. Ultrasound with a frequency of 20 kHz was used to improve the wettability between aramid fibers and epoxy resin during the winding process of the composites. The effects of ultrasound on the viscosity and surface tension of epoxy resin and on the surface characteristics of aramid fibers were investigated. The wettability of aramid fibers and treated epoxy resin under different conditions and of aramid fibers and epoxy resin under ultrasonic online treatment were compared. The results indicated that the main action of ultrasound was to force epoxy resin to impregnate aramid fibers, in addition to the influence of ultrasound on the properties of epoxy resin and aramid fibers. The results of microdebond testing showed that the interfacial shear strength (IFSS) of aramid/epoxy composites could be 26% higher than that of untreated composites because of the improved wettability between aramid fibers and epoxy resin subjected to ultrasonic online treatment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Surface modification of ultra-high strength polyethylene fibers for enhanced adhesion to epoxy resins using intense pulsed high-power ion beam

The effects of intense pulsed high power ion beam (HPIB) treatment of ultra-high strength polyethylene (UHSPE) fibers on the fiber/epoxy resin interface strength were studied. For this study, argon ions were used to treat Spectra? 1000 (UHSPE) fibers in vacuum. Chemical and topographical changes of the fiber surfaces were characterized using Fourier transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), dynamic wettability measurements, and scanning electron microscopy (SEM). The fiber/epoxy resin interfacial shear strength (IFSS) was evaluated by the single fiber pull-out test. The FTIR-ATR and XPS data indicate that oxygen was incorporated onto the fiber surface as a result of the HPIB treatment. The wettability data indicate that the fibers became more polar after HPIB treatment and also more wettable. Although the total surface energy increased only slightly after treatment, the dispersive component decreased significantly while the acid-base component increased by a similar amount. SEM photomicrographs revealed that the surface roughness of the fibers increased following the HPIB treatment. The single fiber pull-out test results indicate that HPIB treatment significantly improved the IFSS of UHSPE fibers with epoxy resin. This enhancement in IFSS is attributed to increased roughness of the fiber surface resulting in mechanical bonding and in increased interface area, increased polar nature and wettability, and an improvement in the acid-base component of the surface energy after the HPIB treatment.     

Controlling the release of active iron and manganese ions from styrene‐butadiene rubber‐binding matrix containing chloride salts of them

A series of epoxy resin composites containing different contents of alkoxysilane functionalized polycaprolactone/polydimethylsiloxane (PCS‐2Si) were prepared after curing with polyamidoamine curing agent at different temperatures. The effects of PCS‐2Si content and curing temperature on morphologies, solvent resistance, and surface properties of the composites were studied. The scanning electron microscope results showed that increasing the PCS‐2Si content and curing temperature caused the changes of miscibility between epoxy and modifier, leading to different morphologies. Other data from solvent swelling and surface tension of composites cured at the same temperature illustrated that the modified epoxy resins with higher content of PCS‐2Si had less crosslinked networks, but lower surface tension. At the same time, the composites cured at higher curing temperature generally had more resistance to chemicals and higher surface tension due to the formation of highly crosslinked networks. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Improving the interfacial and flexural properties of carbon fiber–epoxy composites via the grafting of a hyperbranched aromatic polyamide onto a carbon fiber surface on the basis of solution polymerization

Hyperbranched aromatic polyamide (HBP) was grafted successfully onto carbon fibers (CFs) on the basis of solution polymerization to enhance the interfacial adhesion strength of CF-reinforced epoxy resin composites. The microstructure and interfacial properties of the CFs before and after decoration were researched. The results indicate that HBP was deposited uniformly onto the CFs with γ-aminopropyl triethoxysilane as the bridging agent. The active groups, roughness, and surface energy of the modified fiber [hyperbranched aromatic polyamide grafted carbon fiber (CF–HBP)] increased visibly in comparison with those of the untreated CFs. The CF–HBP composites revealed simultaneous remarkable enhancements (65.3, 34.3, and 84.8%) in their interfacial shear strength, flexural strength, and modulus, respectively; this was attributed to the improvement in the fiber–epoxy interface through enhanced chemical interactions, mechanical interlocking, and wettability. These agreed with the scanning electron microscopy observations from the fracture surface morphologies of the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47232.     

Surface modification of aramid fibers with γ‐ray radiation for improving interfacial bonding strength with epoxy resin

Co⁶⁰ γ‐ray radiation as a simple and convenient method for surface modification of Armos aramid fibers was introduced in this article. Two kinds of gas mediums, N₂ and air, were chosen to modify aramid fiber surface by γ‐ray irradiation. After fiber surface treatment, the interlaminar shear strength values of aramid/epoxy composites were enhanced by about 17.7 and 15.8%, respectively. Surface elements of aramid fibers were determined by XPS, the analysis of which showed that the ratio of oxygen/carbon was increased. The crystalline state of aramid fibers was determined by X‐ray diffraction instrument. The surface topography of fibers was analyzed by atomic force microscopy and scanning electron microscope. The degree of surface roughness and the wettability of fiber surface were both enhanced by γ‐ray radiation. The results indicated that γ‐ray irradiation technique, which is a suitable way of batch process for industrialization, can significantly improve the surface properties of aramid fibers reinforced epoxy resin matrix composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

超声处理改善玻纤织物与双酚A型乙烯基酯树脂浸润性研究

针对玻纤织物增强双酚A型乙烯基酯树脂复合材料的真空灌注成型工艺方法,采用超声处理技术对树脂胶液进行了快速处理。通过树脂胶液粘度、表面张力以及胶液对玻纤织物浸润性的分析表征研究了超声处理效果。结果表明:超声处理1min可使双酚A型乙烯基酯树脂(3301)体系的粘度从6 500mPa.s降低到550mPa.s,表面张力从0.041N/m降低到0.023N/m,处理后树脂对玻璃纤维织物的润湿性得到明显改善。超声辐射可以在树脂体系内引发空化效应和声流搅拌作用,促进树脂在纤维表面的吸附、扩散和渗透。     

Formation of a carbon fiber/polyhedral oligomeric silsesquioxane/carbon nanotube hybrid reinforcement and its effect on the interfacial properties of carbon fiber/epoxy composites

A carbon fiber/polyhedral oligomeric silsesquioxane/carbon nanotube (CF–POSS–CNT) hybrid reinforcement was prepared by grafting CNTs onto the carbon fiber surface using octaglycidyldimethylsilyl POSS as the linkage in an attempt to improve the interfacial properties between carbon fibers and an epoxy matrix. X-ray photoelectron spectroscopy, scanning electron microscopy, dynamic contact angle analysis and single fiber tensile testing were performed to characterize the hybrid reinforcements. Interlaminar shear strength (ILSS), impact toughness, dynamic mechanical analysis and force modulation atomic force microscopy were carried out to investigate the interfacial properties of the composites. Experimental results show that POSS and CNTs are grafted uniformly on the fiber surface and significantly increase the fiber surface roughness. The polar functional groups and surface energy of carbon fibers are obviously increased after the modification. Single fiber tensile testing results demonstrate that the functionalization does not lead to any discernable decrease in the fiber tensile strength. Mechanical property test results indicate the ILSS and impact toughness are enhanced. The storage modulus and service temperature increase by 11 GPa and 17 °C, respectively. POSS and CNTs effectively enhance the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking.     

Polyvinyl butyral-zirconia hybrid hollow fibers prepared by air gap spinning

In this study, an air gap spinning method was adopted to develop polyvinyl butyral (PVB)-zirconium (Zr) hybrid hollow fibers. With zirconium alkoxide, three kinds of PVB with different degree of acetalization were used as organic polymers. The morphologies, surface Zr content and relative bonding inside the hollow fibers were characterized by changing coagulation solution concentration, spinning dope viscosity and air gap distance. The effect of Zr on PVB structure were examined in terms of x-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy. Results indicate that PVB spinning solution experienced good mixing mechanism at room temperature and immediately develop structural hollow fiber when extruded into coagulation fluid of Zr alkoxide by 2.0 cm air gap distance. Among other prepared fibers, fiber contained 20 wt% PVB with 2 cm air gap confirms effective average diameter of about 1016 μm which strongly influenced by spinning solution viscosity. The variation of maximum Zr content (8.18%–14.36%) confirms the asymmetry of coordinate bonding occurred on internal and external surface. Moreover, changing of spinning solution viscosity, coagulation liquid concentration and air gap can only affect the surface roughness and fiber diameter whereas no micro pores were developed in the fiber sublayers.     

Modification of the carbon fiber surface with a copper coating for composite materials with epoxy

Surface treatment of carbon fibers is essential to provide adequate interfacial interaction, and strength in carbon fiber/epoxy composites. The electrodeposition of a metallic copper coating on the carbon fiber surface has been examined as an alternative method to improve carbon fiber-epoxy interfacial properties. The wettability of the carbon fiber by the epoxy resin was improved as a result of copper electrodeposition. As a consequence, the adhesion between the carbon fiber and epoxy was also greatly improved by the surface electrolytic treatment used. The electrodeposition conditions affected significantly both wettability and adhesion phenomena. The electrolytic current had a strong effect on the interface performance. It was found that there was an intermediate electrolytic current, within the range used, which promoted better wetting and composite strength, compared with conventionally surface-oxidized carbon fibers.     

Effect of sizing on interfacial adhesion of commercial high strength carbon fiber‐reinforced resin composites

The influence of sizing agent on interfacial shear strength (IFSS) of carbon fiber/epoxy (CF/EP) and carbon fiber/bismaleimide (CF/BMI) was investigated. Since sizing agent can alter physicochemical properties of CF surface, possible affecting factors, including sizing reactivity, chemical reactions between sizing and resin, wettability of fiber with resin, fiber surface roughness, and chemical composition of fiber surface, were discussed. It is found that contact angle of fiber with resin and sufficient chemical reactions between sizing and resin reveal strong correlation with the interfacial adhesion of CF/EP and CF/BMI, while the effect of surface roughness and the amount of oxygen on the fiber surface are relatively weak. Due to EP type of the composition, the sizing agent tends to improve the wettability of CF with EP, while goes against for the fiber with BMI. POLYM. COMPOS., 254–261, 2016. © 2014 Society of Plastics Engineers