Effects of Atmospheric DBD Plasma Treatment on the Surface Properties of PAN-Based Carbon Fiber

Plasma treatment has been known as an effective way to improve the surface bonding between the reinforcement material and the matrix, by modifying the surface morphology and the chemical composes of the material. In order to investigate the effects of atmospheric dielectric barrier discharge (DBD) plasma treatment on the surface properties of polyacrylonitrile-based (PAN-based) carbon fiber, atomic force microscope(AFM), X-ray photoelectron spectroscopy(XPS), and contact angle test were introduced to compare different treatment duration. The interfacial adhesion of carbon fiber/epoxy (CF/EP) composites were analyzed by a single fiber composite (SFC) for filament fragmentation test. And the tensile strength test and Weibull analysis were carried out to observe whether the etching could affect the strength. The results prove that the DBD plasma improves the surface properties of the carbon fiber. Further, when the treatment time was around 90 s, the roughness and oxygen containing group of the carbon fiber reached the peak values. Also, the fiber showed the best adhesion to the polymer in contact angle test and the optimum interfacial shear strength (IFSS) in fragmentation test. The Weibull analyses of the tensile data revealed no substantial changes in the tensile strength within the treatment time of 180 s.

Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

Effect of Electrochemical Treatment in Aqueous Ammonium Bicarbonate on Surface Properties of PAN-based Carbon Fibers

The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.

Influence of surface treatment of carbon fiberson electrochemical crystallization of calcium phosphate

Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.

Plasma Modification of Activated Carbon Fibers for Adsorption of SO_2

Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.

Preparation and Surface Modification of High-Density Chitosan/Functionalized Multi-walled Carbon Nanotubes Hollow Fibers

Functionalized multi-walled carbon nanotubes( fMWNTs) were prepared with chitosan via controlled surface deposition and crosslinking process and scanning electron microscopy( SEM),Fourier translation infrared spectroscopy( FT-IR) and Xray diffraction( XRD) are used to character properties. A novel high-density chitosan( HCS) was dissolved in f-MWNTs dispersed dilute acetic acid with a maximal concentration of 5. 8%. The hollow fibers can be made by extruding the solution into a dilute alkali solution through a wet-spinning process and the tensile properties of the materials were evaluated by universal tester. The surface property of fibers,pretreated by Helium( He) and the following grafted with gelatin was evaluated with X-ray photoelectron spectroscopy( XPS).As the hollow fibers were intended for neural tissue engineering,its suitability was evaluated in vitro using rat Schwann cells( RSC96) as model cells. The cells attachment,proliferation and morphology,were studied by various microscopic techniques. Based on the results,the gelatin grafted HCS / f-MWNTs hollow fibers could be used as a potential cell carrier in neural tissue engineering.

AN INVESTIGATION ON THE ELECTROLYTIC SURFACE TREATMENT OF CARBON FABRICS

The composites obtained from carbon fibers have poor interlaminar shear strength beacuse ofthe few active polar groups on the carbon fiber surface and the weak bonding between the carbonfiber and the resin matrix. An electrolysis study to increase the surface acidic groups of the carbonfiber was investigated in this paper. Experimental results showed that the surface acidic groups,tensile strength, peeling strength of the carbon fabrics increased under certain electrolytic condi-tions, but the breaking elongations decreased. When the electrolytic conditions were too strong,tensile strength and peeling strength dropped down. Electronic scanning micrographs showed theengraved surfaces of carbon fibers after electrolysis.

Effects of Electrochemical Treatment on the Superficial Properties of Rayon-based Carbon Fibers

The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the carbon fiber surface. The acidity on the surface of the untreated carbon fiber was very low, while for the treated fibers, the acidity increased significantly.Moreover, with the treatment extent proceeded, the acidity on the fiber surface also increased. SEM analysis shows electrochemical treatment under intense treatment degree caused considerable etch on the fiber surface.Cavities and grooves can be observed on the surface via the SEM microphotograph. While in a more mild treatment, electrochemical treatment didn't cause great etch on the surface of the fiber.

Surface Modification of Electrospun Poly(L-lactide)/Poly(ε-caprolactone)Fibrous Membranes by Plasma Treatment and Gelatin Immobilization

Biopolymer fibers have great potential for technical applications in biomaterials.The surface properties of fibers are of importance in these applications.In this study,electrospun poly(L-lactide)(PLLA)/poly(ε-caprolactone)(PCL)membranes were modified by cold plasma treatment and coating gelatin to improve the surface hydrophilic properties.The morphologies of the fibers were observed by scanning electron microscopy(SEM).Atomic force microscopy(AFM)was employed to show the surface characteristics of the fibers.The chemical feature of the fibrous membrane surfaces was examined by X-ray photoelectron spectroscopy(XPS).The surface wettability of the fibrous membrane was also characterized by water contact angle measurements.All these results show that plasma treatment can have profound effects on the surface properties of fibrous membranes by changing their surface physical and chemical features.Gelatin-PLLA/PCL membrane has great potential in applications of tissue engineering scaffolds.

Effect of Rare Earths on Tribological Properties of Carbon Fibers Reinforced PTFE Composites

Carbon fibers （CF） were surface treated with air-oxidation and rare earths （RE）, respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites was invest/gated. Experimental results revealed that RE was superior to air ox/dation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE （CF/PTFE） composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.

Performance of Polyaniline-coated Short Carbon Fibers in Electromagnetic Shielding Coating

Combined nitric acid oxidation method and polyaniline （PANI）-coated method were applied to modify the surface properties of short carbon fibers （SCF）. The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope （SEM）, UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS （X-ray photoelectron spectroscopy） patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF （PAOSCF） revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency （SE） value increased from 1.54 to 23.3 dB.

Effect of Cold Plasma Treatment on the Mechanical Properties of RTM Composites

Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result shows that the surface polarity of carbon fibers was modified by cold plasma treatment, which increases the impregnation of PET braided carbon fibers during the process of resin flowing, improves the interfacial properties of RTM composites, and therefore enhances the mechanical properties of the KTM composites.

Investigation on Mechanism of the Improvement in Tribological Properties of Carbon Fiber Reinforced Polytetrafluoroethylene Composites by Surface Treatment

Tribological properties of polytetrafluoroethylene （PTFE） composites filled with differently surface treated carbon fibers （CF）, sliding against GCr15 steel under dry sliding conditions, were investigated on a block-on-ring M-2000 tribometer. Experimental results reveal that rare earths （RE） surface treatment reduces the friction and wear of CF-reinforced PTFE （CF/PTFE） composites. Scanning electron microscopy （SEM） investigation of worn surfaces of CF/PTFE composites shows that cracks or pores are visible on the worn surfaces of untreated and air-oxidated composite, while no crack and very few pores present on the worn surface of RE- treated composite. The fiber-friction-angling effect makes carbon fibers angled and oriented along the frictional shearing force, and finally parallel to the friction surface, which makes interracial adhesion become a key factor to tribological properties of CF/PTFE composite. With strong interfacial adhesion between carbon fiber and PTFE after RE surface treatment, carbon fibers are not easily detachable from the PTFE matrix in the process of fiber-friction-angling, which prevents the rubbing-off of PTFE, and accordingly improves the friction and wear properties of the composite.

碳纤维表面改性技术研究进展及发展趋势

综述了近几年国内外碳纤维表面改性处理技术的研究进展,分别介绍了涂层改性、氧化改性、表面接枝改性、等离子体改性的改性原理及效果。现有碳纤维表面改性技术仅对表面产生物理或化学的改性,单独一种改性技术在连续化生产中难以实现有效控制,而多种改性技术的组合式应用技术可以相互融合各种改性技术的优点,适合在各个碳纤维生产流程中进行表面改性设计具有更高的研究价值。碳纤维组合式表面改性技术将是未来提升碳纤维连续化生产的发展趋势。

碳纤维材料在桥梁工程维修加固中的应用

交通运输行业的发展对桥梁的承载能力提出了更高的要求,桥梁工程维修加固工作也因此受到了重视。碳纤维材料作为一种新型材料,各方面性能都比较突出,在二次加固施工时也比较适用,因此在桥梁维修加固中扮演着重要的角色。文章对碳纤维材料的特点和桥梁工程维修加固修补技术以及碳纤维材料在桥梁工程维修加固中的应用进行研究。

低维碳材料改性研究进展

综述了近几年包括富勒烯(C_(60))、碳量子点(CQDs)、碳纳米管(CNT)、碳纤维(CF)、石墨烯(GN)在内的低维碳材料改性研究进展,依据碳材料的维度形态对材料进行了分类与概括,并介绍了现有低维碳材料常见的改性方法及意义,助力高性能低维碳材料发展。

等离子体处理对国产高强碳纤维复合材料界面性能影响研究

在100W功率条件下,用氧等离子体对国产T800级碳纤维进行处理,通过扫描电子显微镜、原子力显微镜、X射线光电子能谱、单丝拉伸强度测试等方法对处理前后碳纤维表面物理化学特性进行表征,采用微脱粘方式研究了等离子体处理前后碳纤维环氧树脂复合材料界面的结合性能。结果表明:等离子体处理使碳纤维表面发生明显刻蚀,显著地提高了其表面化学活性;处理时间为3min时,碳纤维力学性能未发生降低,而其复合材料界面剪切强度值(IFSS)可达最高的88.61MPa,相比于未处理碳纤维复合材料而言,IFSS增幅为97.39%。

Cu/ACF adsorbent modified by non-thermal plasma for simultaneous adsorption–oxidation of H_(2)S and PH_(3)

Non-thermal plasma(NTP)surface modification technology is a new method to control the surface properties of materials,which has been widely used in the field of environmental protection because of its short action time,simple process and no pollution.In this study,Cu/ACF(activated carbon fiber loaded with copper)adsorbent was modified with NTP to remove H_(2)S and PH_(3) simultaneously under low temperature and micro-oxygen condition.Meanwhile,the effects of different modified atmosphere(air,N_(2) and NH_(3)),specific energy input(0–13 J/mL)and modification time(0–30 min)on the removal of H_(2)S and PH_(3) were investigated.Performance test results indicated that under the same reaction conditions,the adsorbent modified by NH_(3) plasma with 5 J/mL for 10 min had the best removal effect on H_(2)S and PH_(3).CO_(2) temperature-programmed desorption and X-ray photoelectron spectroscopy(XPS)analyzes showed that NH_(3) plasma modification could introduce amino functional groups on the surface of the adsorbent,and increase the types and number of alkaline sites on the surface.Brunauer-Emmett-Teller and scanning electron microscopy showed that NH_(3) plasma modification did not significantly change the pore size structure of the adsorbent,but more active components were evenly exposed to the surface,thus improving the adsorption performance.In addition,X-ray diffraction and XPS analysis indicated that the consumption of active components(Cu and Cu_(2)O)and the accumulation of sulfate and phosphate on the surface and inner pores of the adsorbent are the main reasons for the deactivation of the adsorbent.

碳纤维表面电化学氧化处理技术研究进展

碳纤维表面光滑、呈现化学惰性,导致与树脂基体间的界面结合力较差,限制了复合材料力学性能的提升。经过电化学氧化处理后,碳纤维表面沟槽加深、变宽,表面粗糙度明显增大,同时接入了具有反应活性的官能团,从而提升了纤维与基体的界面性能。电化学氧化处理具有反应缓和、处理时间短、氧化均匀、能够与生产线配套以及对复合材料的力学性能有明显改善的特点。介绍了碳纤维表面电化学氧化处理用电解质、作用机理、处理工艺、效果评价及存在的问题,并指出了未来的研究方向。

建筑暖通用碳纤维/聚酰胺自增强复合材料的改性研究

为开发建筑暖通用高综合性能建筑复合材料,研究了表面处理和制备工艺对碳纤维和聚酰胺自增强复合材料表面形貌、拉伸性能的影响。结果表明,经过硝酸处理和过氧化氢处理会对碳纤维表面形貌产生明显影响;而丙酮预处理后碳纤维的表面形貌与未处理时基本相同。过氧化氢处理后碳纤维的抗拉强度、断裂伸长率和弹性模量相较未处理碳纤维变化不大或略有降低;而硝酸处理后碳纤维的力学性能降低较为明显。随着压强从1 MPa增至9 MPa或热压温度从170℃增至200℃,聚酰胺自增强复合材料的抗拉强度和弹性模量先增加后减小,在压强为5 MPa、热压温度为180℃时,聚酰胺自增强复合材料取得抗拉强度和弹性模量最大值,分别为141.7 MPa和943.4 GPa。