Influence of surface state on moisture sensitivity of carbon fiber and its composite interfacial properties

Abstract

The influence of surface state on the moisture sensitivity of carbon fiber was analyzed by applying a T800 grade carbon fiber with five different surface conditions, namely, with and without surface oxidation, in the presence or absence of sizing agent. The interfacial properties of their composites in the presence of two epoxy matrices (respectively EP07 and EP10) were also characterized by micro-droplet tests. The overall results show that both oxidized and sizing-coated fibers have higher moisture equilibrium content than that of the pristine unsurface-treated fiber, due to higher amount of activated carbon groups. After moisture absorption of the carbon fibers, almost all the fiber/epoxy systems show decrease in the interfacial shear strength and the unsurface-treated fiber system exhibits the largest decline. Moreover, both interfacial shear strength and interlaminar shear strength of carbon fiber/EP10 composite demonstrate better water resistance performance than that of the carbon fiber/EP07 composite, consistent with DSC results of the two resins.

Keywords

surface state / moisture absorption / carbon fiber / interfacial shear strength

References

[1] Bao LR, Yee AF. Moisture Diffusion and Hygrothermal Aging in Bismaleimide Matrix Carbon Fiber Composites-Part I Uni-Weave Composites[J]. Compos. Sci. Technol., 2002, 62: 2099-2110.

[2] Bao LR, Yee AF. Moisture Diffusion and Hygrothermal Aging in Bismaleimide Matrix Carbon Fiber Composites Part II-Woven and Hybrid Composites[J]. Compos. Sci. Technol., 2002, 62: 2111-2119.

[3] Bao LR, Yee AF. Effect of Temperature on Moisture Absorption in a Bismaleimide Resin and Its Carbon Fiber Composites[J]. Polymer, 2002, 43: 3987-3997.

[4] Karbhari VM, Xian GJ. Hygrothermal Effects on High VF Pultruded Unidirectional Carbon/Epoxy Composites: Moisture Uptake[J]. Composites Part B, 2009, 40: 41-49.

[5] Wan YZ, Wang YL, Luo HL, et al. Moisture Absorption Behavior of C3D/EP Composite and Effect of External Stress[J]. Mater. Sci. Eng. A, 2002, 326: 324-329.

[6] Wan YZ, Wang YL, Huang Y, et al. Moisture Absorption in a Threedimensional Braided Carbon/Kevlar/Epoxy Hybrid Composite for Orthopaedic Usage and its Influence on Mechanical Performance[J]. Composites Part A, 2006, 37: 1480-1484.

[7] Kumar SB, Sridhar I, Sivashanker S. Influence of Humid Environment on the Performance of High Strength Structural Carbon Fiber Composites[J]. Mater. Sci. Eng. A, 2008, 498: 174-178.

[8] Bullions TA, Loos AC, McGrath JE. Moisture Sorption Effects on and Properties of a Carbon Fiber-reinforced Phenylethynyl-terminated Poly(etherimide)[J]. J. Compos. Mater., 2003, 37(9): 791-809.

[9] Pandey G, Kareliya C, Hinkley J, et al. Interfacial Micromechanics and Effect of Moisture on Fluorinated Epoxy Carbon Fiber Composites [J]. Polym. Compos., 2011, 32: 1961-1969.

[10] Cauich-Cupul JI, Perez-Pacheco E, Valadez-Gonzalez A, et al. Effect of Moisture Absorption on the Micromechanical Behavior of Carbon Fiber/Epoxy Matrix Composites[J]. J. Mater. Sci., 2011, 46: 6664-6672.

[11] Zafar A, Bertocco F, Schjødt-Thomsen J, et al. Investigation of the Long Term Effects of Moisture on Carbon Fibre and Epoxy Matrix Composites[J]. Compos. Sci. Technol., 2012, 72: 656-666.

[12] Wang SK, Chung DDL. Effect of Moisture on the Interlaminar Interface of a Carbon Fiber Polymer-matrix Composite, Studied by Contact Electrical Resistivity Measurement[J]. Compos. Interfaces, 2002, 9(5): 453-458.

[13] Sekulic D, Bozic D, Babic B, et al. Moisture and Gamma-ray Irradiation Effects on the Mechanical Properties of Carbon Fibre-reinforced Plastics [J]. J. Microsc., 2008, 232(3): 611-617.

[14] Selzer R, Friedrich K. Mechanical Properties and Failure Behaviour of Carbon Fibre-reinforced Polymer Composites under the Influence of Moisture[J]. Composites Part A, 1997, 28A: 595-604.

[15] Choi HS, Ahn KJ, Nam JD, et al. Hygroscopic Aspects of Epoxy/Carbon Fiber Composite Laminates in Aircraft Environments[J]. Composites Part A, 2001, 32: 709-720.

[16] Sala G. Composite Degradation due to Fluid Absorption[J]. Composites Part B, 2000, 31: 357-373.

[17] Perez-Pacheco E, Cauich-Cupul JI, Valadez-Gonzalez A, et al. Effect of Moisture Absorption on the Mechanical Behavior of Carbon Fiber/ Epoxy Matrix Composites[J]. J. Mater. Sci., 2013, 48: 1873-1882.

[18] Zai BA, Park MK, Choi HS, et al. Effect of Moisture Absorption on Damping and Dynamic Stiffness of Carbon Fiber/Epoxy Composites[J]. J. Mech. Sci. Technol., 2009, 23(11): 2998-3004.

[19] Wan XF, Wang YL, Zhou FG, et al. Moisture Absorption Behavior of Carbon Fiber-reinforced Monomer Casting Nylon Composites[J]. J. Reinf. Plast. Compos., 2004, 23(10): 1031-1040.

[20] Khan LA, Mahmood AH, Syed AS, et al. Effect of Hygrothermal Conditioning on the Fracture Toughness of Carbon/Epoxy Composites Cured in Autoclave/Quickstep[J]. J. Reinf. Plast. Compos., 2013, 32(16): 1165-1176.

[21] Yao LR, Li M, Wu Q, et al. Comparison of Sizing Effect of T700 Grade Carbon Fiber on Interfacial Properties of Fiber/BMI and Fiber/ Epoxy [J]. Appl. Surf. Sci., 2012, 263: 326-333.