CF/PPEK、CF/PPES单向板的制备工艺和力学性能研究

本文研究了碳纤维增强杂萘联苯聚醚酮(CF／PPEK)和碳纤维增强杂萘联苯聚醚砜(CF／PPES)2种复合材料单向板的预浸热压成型工艺，对制备的单向板进行了力争巨能试验研究，并利用X射线光电子能谱(XPS)和扫描电子显微镜(SEM)对这两种复合材料的界面状态和结构进行了分析．研究表明，由于PPEK和PPES分子结构的特点，使其具有良好的韧性和高温性能，且可与碳纤雏形成良好的复合界面，从而有效地缓解应力集中，提高其复合材料的力学性能，并具有良好的成型加工特性，同时，在250℃高温条件下的拉伸和弯曲强度和模量保留率均达到60％以上，这些结果为进一步研究和应用这种高性能热塑性复合材料提供了一定的参考依据．     

表面处理对PA6/CF复合材料力学性能与破坏形态的影响

通过碳纤维(CF)表面官能团的酰氯化,利用酰氯作为己内酰胺阴离子聚合的活化剂,成功地制备了表面接枝尼龙6(PA6)的CF。研究了表面己内酰胺稳定化并阴离子接枝PA6的CF对PA6／CF复合材料力争性能与破坏形态的影响。结果表明,表面接枝PA6后的PA6／CF复合材料界面相互匹配,改善了复合材料界面的相互作用,提高了复合材料的剪切强度,复合材料剪切破坏呈部分非界面脱粘破坏。     

碳纤维/聚醚酮酮界面强度影响因素的研究进展

碳纤维(CF)增强聚醚酮酮(PEKK)复合材料具有强度高、韧性好、工艺简易等优点,已成为一种极具潜力的热塑性复合材料。现有方法制备的复合材料中CF和PEKK的界面黏结强度依然不高,给其实际应用造成了困难。本文对CF/PEKK复合材料研究现状进行总结,通过分析界面结构及性能对应力传递所发挥的作用,归纳影响界面强度的关键因素。其中浸润理论、化学键理论、物理吸附理论可有效用于界面改性的机理分析。而针对CF/PEKK复合材料,可通过调节PEKK分子中的对苯和间苯比例或发展聚醚酮类上浆剂来进一步提高其界面性能。     

沸水对PI/CF复合材料界面作用机理的研究

研究了聚酰亚胺(PI)／碳纤维(CF)复合材料界面在沸水中的稳定性。结果表明,经沸水浸泡后的复合材料层间剪切强度和界面剪切强度均有所提高,且随水煮时间的延长而增大;试样断面观察表明,水没有对复合材料界面产生破坏作用,力学性能的变化与基体／纤维界面粘结的湿热稳定性有直接关系;沸水对界面的作用机理是,在PI／CF复合材料的界面区,树脂的水解使氢键的数量增加,形成了防水层,阻碍了水沿界面的侵入,同时水松驰了界面局部应力。     

Ⅳ型高压储氢气瓶用碳纤维复合材料界面表征与分析

Ⅳ型高压储氢气瓶的结构载荷主要由外层碳纤维复合材料(CFRP)承载。良好的碳纤维(CF)与环氧树脂(EP)界面性能有助于载荷传递，使CF强度发挥至最大化，提高压力容器的安全性能，另外可以减少CFRP用量，降低成本，从而打破高昂价格带来的应用局限。通过扫描电镜、原子力显微镜、X射线电子能谱仪、动态接触角、微脱黏测试仪及万能试验机对CFRP界面进行了系统的表征与分析。通过分析CF的表面形态、化学成分、润湿性、表面能及界面结合力，揭示了CFRP力学性能与界面性能的相关性。研究表明，CF表面利于形成机械互锁的表面粗糙度、利于化学键结合的含氧活性官能团、利于润湿的极性组分表面能等因素可以增强其与EP的界面结合，最大程度发挥CF的力学性能，使高压容器承载复合材料具有稳定的力学性能。     

碳纤维增强MC尼龙复合材料吸湿行为研究

采用液态原位聚合法制备了碳纤维(CF)增强浇铸尼龙(MC尼龙)复合材料,研究了其吸湿行为?分别考察了CF体积分数、CF编织结构和外加载荷对MC尼龙／CF复合材料吸湿行为的影响。结果表明,随着CF体积分数的增加,复合材料的平衡吸湿率减小;三维编织结构的CF增强MC尼龙复合材料的吸湿速率及平衡吸湿率均低于长的CF增强MC尼龙;外加载荷使该复合材料的吸湿能力降低。     

炭纤维增强热塑性工程塑料的研制

研究炭纤维在尼龙、聚甲醛两种工程塑料中的含量对复合材料抗拉强度、冲击强度及耐磨性的影响，并利用扫描电子显微镜观察复合材料的界面结构。结果表明，在CF／PA1010复合材料中，当炭纤维含量达到30％时，抗拉强度达到127．6MPa，耐磨性显著提高。     

高性能复合材料弯曲疲劳性能研究

用湿法缠绕技术制作了CF／5228预浸料,对热压罐固化的CF／5228复合材料的力学性能和弯曲疲劳性能进行了研究,并用扫描电镜、电子显微镜等对复合材料的疲劳损伤机理进行了微观表征和理论探讨。研究表明,M40J／5228复合材料比M40／5228具有更为优异的耐疲劳性能。复合材料的疲劳损伤主要有纤维断裂、基体开裂和界面剪切破坏3种表现形式,通常复合材料构件的疲劳破坏多为3种形式的综合表现。基体增韧、选用高强高模碳纤维、界面强化和铺层优化是提高复合材料构件耐疲劳性能有效手段。     

碳纤维增强聚醚醚酮复合材料的界面改性

由于其优异的性能.碳纤维(CF)增强聚醚醚酮(PEEK)热塑性复合材料是近年来先进复合材料研发的热点.但因PEEK熔融黏度大、CF丝束密集且具有化学惰性,树脂对纤维丝束浸渍困难和界面相互作用弱阻碍了高性能热塑性复合材料广泛应用,放改进界面性能是研究的重点.本文采用聚醚酰亚胺(PEI)以及聚醚酰亚胺/氧化石墨烯(PEI/...     

聚丙烯/短切碳纤维复合材料的界面相容性与力学性能的研究

环氧树脂上浆的市售碳纤维(CF)与聚丙烯(PP)相容性较差,影响PP/CF复合材料的性能。通过上浆与无上浆的T700短切CF制备PP/CF复合材料,以马来酸酐接枝聚丙烯(PP-g-MAH)作为相容剂与PP/CF制备PP/CF/PP-g-MAH复合材料。研究含有不同上浆剂的CF对复合材料的界面相容性和力学性能的影响。结果表明:中复神鹰上浆剂使复合材料相容性提升,结晶度下降,冲击强度提高;添加PP-g-MAH后,上浆剂与其相容性良好,提高复合材料的界面结合性、拉伸强度与冲击强度。东丽上浆剂对复合材料的结晶度无明显影响,但提高复合材料的冲击强度;添加PP-g-MAH后,上浆剂与其相容性较差,较无上浆复合材料,上浆复合材料界面结合性降低,导致拉伸强度与冲击强度略微下降。     

Tailoring Carbon Fiber/Carbon Nanotubes Interface to Optimize Mechanical Properties of Cf‐CNTs/SiC Composites

C_f/SiC composites were fabricated using fiber coatings including CNTs and matrix infiltration using the polymer impregnation and pyrolysis process. Interface between fiber and CNTs (CF/CNTs) was tailored to optimize mechanical properties of hybrid composites. The tailored interphases, such as Pyrocarbon (PyC) and PyC/SiC, protect fibers from degradation during the growth of CNTs successfully. Hybrid composites with well‐tailored CF/CNTs interface displayed significantly increased mechanical strength (352 ± 21 MPa) compared with that (34 ± 3 MPa) of composites reinforced with CNTs, which grown on carbon fibers directly. The interfacial bonding strength of hybrid composites was improved and optimized by tailoring the CF/CNTs interface. Interfacial failure modes were studied, and a firm interface bonding at the joint where CNTs grown was observed.     

Improvement of interfacial interactions in CF/PEEK composites by an s-PSF/graphene oxide compound sizing agent

The interfacial interactions of carbon fiber (CF)-reinforced polymer composites is a key factor affecting the overall performance of the material. In this work, we prepared a sulfonated poly(ether sulfone)–graphene oxide mixed sizing agent to modify the interface of CF/PEEK composites and improve the interfacial properties between the PEEK matrix and CF. Results showed that the mechanical and interfacial properties of CF/PEEK composites are improved by the sizing agent. Specifically, the flexural strength, flexural modulus and interlaminar shear strength of the materials reached 847.29 MPa, 63.77 GPa, and 73.17 MPa, respectively. Scanning electron microscopy confirmed markedly improved adhesion between the resin matrix and fibers. This work provides a simple and effective method for the preparation of high-performance CF/PEEK composites, which can improve the performance of composites without degrading the mechanical property of pristine CF.     

Improved interfacial adhesion in carbon fiber/poly (ether ether ketone) composites with the sulfonated poly (ether ether ketone) sizing treatment

A water-soluble sulfonated poly (ether ether ketone) (SPEEK) sizing agent is prepared and applied to improve the interfacial adhesion of carbon fiber/poly (ether ether ketone) (CF/PEEK) composites. The surface morphology, surface roughness, surface chemistries, and surface free energy of SPEEK sized CF are obtained to understand the sizing effect. The results reveal the increased surface free energy and surface roughness of SPEEK sized CF. In addition, a chemical reaction between the CF surface and sizing layer is proved based on the results of XPS, IR, and ¹H NMR. The interfacial structure of CF/PEEK composites is further ascertained by AFM and the appearance of gradient interface could be verified for SPEEK sized CF/PEEK composites. The formation of the gradient interface is due to the chemical reaction between the CF and sizing agent as well as the improved compatibility between the sized CF and matrix, which benefits the improvement of interfacial adhesion.     

Mechanical,morphology, and thermal properties of carbon fiber reinforced poly(butylene succinate) composites

Biodegradable poly(butylene succinate) (PBS)/carbon fiber (CF) composites were prepared by melt blending method using twin‐screw extruder followed by injection molding. Mechanical properties, crystallization behavior, morphology, crystal structure, and thermal stability of PBS/CF composites were investigated with different CF contents (0, 5, 10, 15, and 20 wt%). It was found that the tensile and impact properties of the composites were improved markedly with the addition of CF; while too much CF would lead to agglomeration and thus weaken the improvement. Scanning electron microscopic photographs on the fracture surfaces showed superior interfacial adhesion between fibers and PBS matrix. Crystallization peak temperature of PBS in its composites was increased due to the heterogeneous effect of CF. The spherulite size of PBS/CF composites decreased and the nucleation density increased drastically. The crystal structure was not affected by the incorporation of CF, as confirmed from the wide‐angle X‐ray diffraction analysis. thermogravimetric analysis showed that the thermal stability of PBS/CF composites was also enhanced. POLYM. COMPOS., 36:1335–1345, 2015. © 2014 Society of Plastics Engineers     

The Tribological Properties of Oxidation-Treated Carbon Fiber-Reinforced PTFE Composite under Oil-Lubricated Conditions

The effect of air-oxidation and ozone surface treatment of carbon fibers (CF) on tribological properties of CF reinforced Polytetrafluoroethylene (PTFE) composites under oil-lubricated condition was investigated. Experimental results revealed that ozone treated CF reinforced PTFE (CF/PTFE) composite had the lowest friction coefficient and wear. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with PTFE matrix.     

Interfacial improvement of carbon fiber-reinforced methylphenylsilicone resin composites with sizing agent containing functionalized carbon nanotubes

A liquid sizing agent containing multiwall carbon nanotubes (MWCNTs) was prepared for carbon fiber (CF) reinforced methylphenylsilicone resin (MPSR) composite applications. In order to improve the dispersion of MWCNTs in the sizing agent and interfacial adhesion between CF and MPSR, MWCNTs and CF were functioned by the chemical modification with tetraethylenepentamine (TEPA) used as a MPSR curing agents. The CF before and after the sizing treatment-reinforced MPSR composites were prepared by a compression molding method. The microstructures, interfacial properties, and impact toughness of CF were systematically investigated. Experimental results revealed that a thin layer of MPSR coating containing functionalized MWCNTs (MWCNT-TEPA) was uniformly grafted onto the surface of CF. The sized CF-reinforced MPSR composite showed simultaneously remarkable enhancement in the interlaminar shear strength and impact toughness. Meanwhile, the tensile strength of CF had no obvious decrease after sizing treatment. In addition, the interfacial reinforcing and toughening mechanisms were also discussed. We believe that the facile and effective method in preparing multifunctional fibers provides a novel interface design strategy of carbon fiber composites for different applications.     

Mechanical properties of carbon fiber composites modified with graphene oxide in the interphase

The surface topographies of carbon fibers treated by sizing agents with different graphene oxide (GO) content were investigated by scanning electron microscopy. The surface elements compositions of carbon fibers were determined by X‐ray photoelectron spectrometer. The interfacial properties of composites were studied by interfacial shear strength. The thermo‐mechanical properties of two typical specimens (CF‐G0 and CF‐G1 composites) were investigated by dynamic mechanical thermal analysis. The results showed the introduction of GO sheets on carbon fibers surfaces effectively improved the mechanical properties of carbon fibers/epoxy composites. POLYM. COMPOS., 38:2425–2432, 2017. © 2016 Society of Plastics Engineers     

Effects of polyhedral oligomeric silsesquioxane coatings on the interface and impact properties of carbon‐fiber/polyarylacetylene composites

Two kinds of polyhedral oligomeric silsesquioxane (POSS) coatings were used for the modification of the interface in carbon fiber (CF) reinforced polyarylacetylene (PAA) matrix composites. The effects of the organic–inorganic hybrid POSS coatings on the properties of the composites were studied with short‐beam‐bending, microdebonding, and impact tests. The interlaminar shear strength and interfacial shear strength showed that the POSS coatings resulted in an interfacial property improvement for the CF/PAA composites in comparison with the untreated ones. The impact‐test results implied that the impact properties of the POSS‐coating‐treated composites were improved. The stiffness of the interface created by the POSS coatings was larger than that of the fiber and matrix in the CF/PAA composites according to the force‐modulation‐mode atomic force microscopy test results. The rigid POSS interlayer in the composites enhanced the interfacial mechanical properties with a simultaneous improvement of the impact properties; this was an interesting phenomenon in the composite‐interface modification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5202–5211, 2006     

Self-healing interfaces of poly(methyl methacrylate) reinforced with carbon fibers decorated with carbon quantum dots

Fiber-polymer matrix interfacial debonding is often observed when mechanical loads are applied to fiber reinforced polymer composites. These defects usually end-up leading to a catastrophic fracture of the composites. In this work, carbon quantum dots (CDs) were incorporated on the surface of carbon fibers (CF), and poly(methyl methacrylate) (PMMA) composites with these modified fibers were able to restore their original properties after been previously damaged. To this end, CDs were synthesized and used to decorate the surface of CF. These decorated CF were then incorporated into PMMA by using a high intensity mixer. The prepared composites were submitted to dynamic mechanical, three-point bending and self-healing tests. Fluorescent CDs with diameters of 10 nm and functional groups, such as amine and carboxylic groups were successfully synthesized by the microwave pyrolysis method. The deposition of CDs on the surface of CF was evaluated and quantified by UV–vis spectroscopy and 1.2 wt.% of CDs on CF was determined. Composites with different surface treatments (including the presence of CD) did not show significant differences in strength, stiffness and damping, suggesting that the surface treatments on CF did not lead to major changes in the degree of interfacial interaction. Self-healing tests showed that damaged composites with CD decorated CF were able to restore their original properties, while no self-healing effect was noted in composites with no CD on CF. The observed self-healing behavior between PMMA and CF decorated with CD is due to the interactions between chemical groups on the surface of the CD and PMMA. Thus, damages related to fiber-matrix interfacial detachments can be repaired through reversible interactions based on CD.     

High improvement of interfacial and mechanical properties in reinforced PP composite by grafting polyethyleneimine modified carboxylic multi-walled carbon nanotubes on short carbon fiber

The properties of carbon fiber reinforced polymer composites (CFRPs) will benefit greatly from improving interfacial performance. In this study, the interfacial properties of the PEI-CNT-CF/PP composite was improved by coating polyethyleneimine (PEI) modified carboxylic multi-walled carbon nanotubes (CNTs) in aqueous solution (PEI-CNT) onto the surface of the CF (PEI-CNT-CF) to form a network structure. The network formation changed the chemical characteristics and compatibility of CF surface by introducing amine (imine) groups, and could induce transcrystallization (TC) at interface of composite. These positive factors led to a 24.6% increasement in the interfacial shear strength (IFSS) of PEI-CNT-CF/PP, and further resulted in 16.2% and 5.3% improvement in tensile and flexural strength, respectively. SEM images of the fracture surface demonstrated a significant improvement in the interfacial adhesion between PEI-CNT-CF and PP resin. These results indicated that the PEI-CNT was a great choice to strengthen the interface of CF/PP system.