Interlaminar properties and toughening mechanisms of aligned carbon nanotube fiber veil interleaved carbon fiber/epoxy composites
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摘要: 碳纤维增强树脂基复合材料(CFRP)由于比强度高、比模量高等优异性能应用广泛，但受层状结构特性和环氧树脂本征脆性影响，其沿厚度方面的力学性能较差，在遭受面外冲击和面内压缩载荷下容易发生分层，进而降低复合材料强度，因此提高该复合材料的层间断裂韧性尤为重要。本文通过在复合材料层间区域引入高度取向的碳纳米管(CNT)纤维纱来提升其层间断裂韧性。为确保纤维纱被树脂充分浸润，首先将其浸泡于经丙酮稀释的环氧树脂溶液中，待丙酮挥发后，将之插层于自制碳纤维预浸料的层间区域，随后借助热压工艺固化成型。通过ASTM标准对增韧样品的I型和II型层间断裂韧性进行了评估，并结合横截面的光学显微观察和断裂面的扫描电镜分析，清晰地显示了裂纹的扩展路径，并揭示了CNT纤维纱的层间增韧机制。结果表明：CNT纤维纱增韧样品的I型和II型层间断裂韧性分别提高37.4%和41.8%。其增韧机制主要包括增韧树脂、加强碳纤维桥接及引发裂纹偏转等。
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关键词:
- 碳纳米管纤维纱 /
- 层间增韧 /
- 纤维桥接 /
- 裂纹偏转 /
- 碳纤维增强树脂基复合材料
Abstract: Carbon fiber reinforced polymer (CFRP) composites are widely used because of their excellent properties such as high specific strength and high specific modulus, but their mechanical properties along the thickness are poor due to the laminar structure characteristics and the intrinsic brittleness of epoxy resin, and they are prone to delamination under out-of-plane impact and in-plane compression loads, which in turn reduce the strength of the composites. Therefore it is especially important to improve the interlaminar fracture toughness of the composites. In this paper, we attempt to improve the interlaminar fracture toughness of the composite by introducing highly oriented carbon nanotube (CNT) fiber veils in the interlaminar region. To ensure that the fiber veils are well infiltrated by the resin, they are first immersed in an epoxy resin solution diluted with acetone. After the acetone evaporated, it is inserted into the interlayer region of the homemade carbon fiber prepreg and subsequently cured by a hot pressing process. The mode I and mode II interlaminar fracture toughness of the toughened samples are evaluated via ASTM testing standards. Combined with the optical microscopic observation of the cross-section and scanning electron microscopy analysis of the fracture surface, the crack propagation paths are clearly shown and the interlaminar toughening mechanisms of CNT fiber veils are revealed. The results show that the mode I and mode II interlaminar fracture toughness of CNT veil toughened samples are improved by 37.4% and 41.8%, respectively. The toughening mechanisms mainly include matrix toughening, strengthening carbon fiber bridging and crack deflection.-
Key words:
- carbon nanotube veil /
- interlaminar toughening /
- fiber bridging /
- crack deflection /
- CFRP
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图 3 取向CNT纤维纱插层碳纤维/环氧树脂复合材料I型断裂测试结果：(a) 样品的载荷-裂纹张开位移图；(b) I型断裂测试的R曲线；(c) I型断裂韧性GIC平均值
Figure 3. Mode I fracture test results of aligned CNT fiber veil interleaved carbon fiber/epoxy composites: (a) Load-crack opening displacement diagram of the sample; (b) R curves of mode I fracture test; (c) Mean value of mode I fracture toughness GIC
图 4 (a) 基准样的I型断裂面；((b), (c)) 断裂表面在不同倍率下的电镜图像
Figure 4. (a) Fracture surface of baseline under mode I fracture test; ((b), (c)) SEM images of fracture surface at different magnifications
图 5 裂纹开裂面中CNT与环氧树脂结合形貌
Figure 5. Morphology of CNT and epoxy resin in cracking surface
图 6 (a) 双悬臂梁(DCB)测试过程中的碳纤维桥接；((b)~(e)) 裂纹截面扫描电镜图
Figure 6. (a) Carbon fiber bridging during the double cantilever beam (DCB) test; ((b)~(e)) SEM images of crack section
图 7 (a) 双悬臂梁试样；不同裂纹位置的金相抛光图像((b)~(d))及其对应开裂面的扫描电镜图像((e)~(g))
Figure 7. (a) Double cantilever beam specimen; Metallographic polishing images ((b)-(d)) at different cracking positions and SEM images ((e)-(g)) of corresponding cracking surfaces
图 8 取向CNT纤维纱插层碳纤维/环氧树脂复合材料裂纹偏转之后的II型断裂测试结果：(a) 载荷-位移曲线；(b) II型断裂韧性平均值GIIC
Figure 8. Mode II fracture test results of aligned CNT fiber veil interleaved carbon fiber/epoxy composites after crack deflection: (a) Load-extension curves; (b) Mean value of mode II fracture toughness GIIC
图 9 取向CNT纤维纱插层碳纤维/环氧树脂复合材料裂纹未偏转的II型断裂测试结果：(a) 载荷-位移曲线；(b) II型断裂韧性平均值
Figure 9. Mode II fracture test results of aligned CNT fiber veil interleaved carbon fiber/epoxy composites before crack deflection: (a) Load-extension curves; (b) Mean value of mode II fracture toughness
图 10 基样II型断裂面的扫描电镜图
Figure 10. SEM images of the mode II fracture surface of the baseline
图 11 CNT纤维纱增韧样品II型断裂面的扫描电镜图
Figure 11. SEM images of the mode II fracture surface of the CNT veil toughening sample
表 1 CNT veil参数
Table 1. Parameters of CNT veil
Parameter Thickness
/μmDensity of surface/(g·m−2) Diameter of CNT/nm Value 5±0.5 2.59-3.70 6-15 
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表 2 不同区域的断裂韧性对比
Table 2. Comparison of fracture toughness at different regions
Crack length/mm GIC/(J·m−2) Baseline CNT veil 50-75 730±90 1137±43 (+55.8%) 75-100 869±67 1092±62 (+25.7%) 50-100 810±76 1112±50 (+37.4%)
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[1] MUGAHED AMRAN Y H, ALYOUSEF R, RASHID R S M, et al. Properties and applications of FRP in strengthening RC structures: A review[J]. Structures,2018,16:208-238. doi: 10.1016/j.istruc.2018.09.008 [2] BOON Y D, JOSHI S C. A review of methods for improving interlaminar interfaces and fracture toughness of laminated composites[J]. Materials Today Communications,2020,22:100830. doi: 10.1016/j.mtcomm.2019.100830 [3] LU W, ZU M, BYUN J H, et al. State of the art of carbon nanotube fibers: Opportunities and challenges[J]. Advanced Materials,2012,24(14):1805-1833. [4] IIJIMA S. Helical microtubules of graphitic carbon[J]. Nature,1991,354(6348):56-58. doi: 10.1038/354056a0 [5] TREACY M M J, EBBESEN T W, GIBSON J M. Exceptionally high Young's modulus observed for individual carbon nanotubes[J]. Nature,1996,381(6584):678-680. doi: 10.1038/381678a0 [6] WONG E W, SHEEHAN P E, LIEBER C M. Nanobeam mechanics: Elasticity, strength, and toughness of nanorods and nanotubes[J]. Science,1997,277(5334):1971-1975. [7] OUYANG Q, WANG X, LIU L. High crack self-healing efficiency and enhanced free-edge delamination resistance of carbon fibrous composites with hierarchical interleaves[J]. Composites Science and Technology,2022,217:109115. doi: 10.1016/j.compscitech.2021.109115 [8] GODARA A, MEZZO L, LUIZI F, et al. Influence of carbon nanotube reinforcement on the processing and the mechanical behaviour of carbon fiber/epoxy composites[J]. Carbon,2009,47(12):2914-2923. doi: 10.1016/j.carbon.2009.06.039 [9] WARRIER A, GODARA A, ROCHEZ O, et al. The effect of adding carbon nanotubes to glass/epoxy composites in the fibre sizing and/or the matrix[J]. Composites Part A: Applied Science and Manufacturing,2010,41(4):532-538. doi: 10.1016/j.compositesa.2010.01.001 [10] KIM M, RHEE K, LEE J, et al. Property enhancement of a carbon fiber/epoxy composite by using carbon nanotubes[J]. Composites Part B: Engineering,2011,42(5):1257-1261. doi: 10.1016/j.compositesb.2011.02.005 [11] DE VOLDER M F, TAWFICK S H, BAUGHMAN R H, et al. Carbon nanotubes: Present and future commercial applications[J]. Science,2013,339(6119):535-539. doi: 10.1126/science.1222453 [12] ALMUHAMMADI K, ALFANO M, YANG Y, et al. Analysis of interlaminar fracture toughness and damage mechanisms in composite laminates reinforced with sprayed multi-walled carbon nanotubes[J]. Materials & Design,2014,53:921-927. [13] WICKS S S, WANG W, WILLIAMS M R, et al. Multi-scale interlaminar fracture mechanisms in woven composite laminates reinforced with aligned carbon nanotubes[J]. Composites Science and Technology,2014,100:128-135. doi: 10.1016/j.compscitech.2014.06.003 [14] BOROWSKI E, SOLIMAN E, KANDIL U F, et al. Interlaminar fracture toughness of CFRP laminates incorporating multi-walled carbon nanotubes[J]. Polymers,2015,7(6):1020-1045. doi: 10.3390/polym7061020 [15] GOJNY F H, WICHMANN M H, FIEDLER B, et al. Influence of different carbon nanotubes on the mechanical properties of epoxy matrix composites—A comparative study[J]. Composites Science and Technology,2005,65(15):2300-2313. doi: 10.1016/j.compscitech.2005.04.021 [16] VILATELA J J, KHARE R, WINDLE A H. The hierarchical structure and properties of multifunctional carbon nanotube fibre composites[J]. Carbon,2012,50(3):1227-1234. doi: 10.1016/j.carbon.2011.10.040 [17] OU Y, GONZÁLEZ C, VILATELA J J. Interlaminar toughening in structural carbon fiber/epoxy composites interleaved with carbon nanotube veils[J]. Composites Part A: Applied Science and Manufacturing,2019,124:105477. doi: 10.1016/j.compositesa.2019.105477 [18] NGUYEN F, TUN S, HARO A, et al. Interlaminar reinforcement by aligned carbon nanotubes in carbon fiber reinforced polymer composites[C]//19th International Conference on Composite Materials (ICCM). Montréal: ICCM, 2013: 3873-3880. [19] NISTAL A, FALZON B G, HAWKINS S C, et al. Enhancing the fracture toughness of hierarchical composites through amino-functionalised carbon nanotube webs[J]. Composites Part B: Engineering,2019,165:537-544. doi: 10.1016/j.compositesb.2019.02.001 [20] DI LEONARDO S, NISTAL A, CATALANOTTI G, et al. Mode I interlaminar fracture toughness of thin-ply laminates with CNT webs at the crack interface[J]. Composite Structures,2019,225:111178. doi: 10.1016/j.compstruct.2019.111178 [21] 李强, 殷新意, 于妍妍, 等. 取向碳纳米管/环氧树脂复合薄膜制备及结构/性能表征[J]. 复合材料学报, 2021, 38(9):2767-2775.LI Qiang, YIN Xinyi, YU Yanyan, et al. Preparation and characterization of aligned carbon nanotubes/epoxy composite films[J]. Acta Materiae Compositae Sinica,2021,38(9):2767-2775(in Chinese). [22] American Society for Testing and Materials. Standard test method for mode I interlaminar fracture toughness of unidirectional fiber-reinforced polymer matrix composites: ASTM D5528-01[S]. Pennsylvania: ASTM International, 2007. [23] American Society for Testing and Materials. Standard test method for determination of the mode II interlaminar fracture toughness of unidirectional fiber-reinforced polymermatrix composites: ASTM D7905[S]. Pennsylvania: ASTM International, 2014. [24] 张远, 于妍妍, 何静宇, 等. 碳纳米管薄膜增强复合材料I型断裂韧性研究[J]. 炭素技术, 2018, 37(4):15-20, 32.ZHANG Yuan, YU Yanyan, HE Jingyu, et al. The model I fracture toughness of composites enhanced by using carbon nanotube film[J]. Carbon Techniques,2018,37(4):15-20, 32(in Chinese). [25] HERRÁEZ M, PICHLER N, BOTSIS J. Improving delamination resistance through tailored defects[J]. Composite Structures,2020,247:112422. doi: 10.1016/j.compstruct.2020.112422 [26] KHAN R. Fiber bridging in composite laminates: A literature review[J]. Composite Structures,2019,229:111418. doi: 10.1016/j.compstruct.2019.111418 [27] BASOGLU M F, ZERIN Z, KEFAL A, et al. A computational model of peridynamic theory for deflecting behavior of crack propagation with micro-cracks[J]. Computational Materials Science,2019,162:33-46. doi: 10.1016/j.commatsci.2019.02.032 [28] SHIN Y C, KIM S M. Enhancement of the interlaminar fracture toughness of a carbon-fiber-reinforced polymer using interleaved carbon nanotube buckypaper[J]. Applied Sciences,2021,11(15):6821. doi: 10.3390/app11156821 -
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