Interface enhancement of carbon fiber reinforced unsaturated polyester composites with sizing agent containing carbon nanotubes

A very interesting field of research on advanced composite materials is the possibility to integrate new functionalities and specific improvements acting on the matrix of the composite by means of a nanocharged resin. In this way, the composite becomes a so-called “multiscale composite” in which the different phases change from nano to macro scale. For example, the incorporation of nanoscale conductive fillers with intrinsically high electrical conductivity could allow a tailoring of this property for the final material. The properties of carbon nanotubes (CNT) make them an effective candidate as fillers in polymer composite systems to obtain ultralight structural materials with advanced electrical and thermal characteristics. Nevertheless, several problems are related to the distribution in the matrix and to the processability of the systems filled with CNT. Existing liquid molding processes such as resin transfer molding (RTM) and vacuum-assisted resin transfer molding (VARTM) can be adapted to produce carbon fiber reinforced polymer (CFRP) impregnated with CNT nanofilled resins. Unfortunately, the loading of more than 0.3-0.5% of CNT can lead to high resin viscosities that are unacceptable for such kind of processes. In addition to the viscosity issues that are related to the high CNT content, a filtration effect of the nanofillers caused by the fibrous medium may also lead to inadequate final component quality. This work describes the development of an effective manufacturing process of a fiber-reinforced multiscale composite panel, with a tetra-functional epoxy matrix loaded with carbon nanotubes to increase its electrical properties and with GPOSS to increase its resistance to fire. A first approach has been attempted with a traditional liquid infusion process. As already anticipated, this technique has shown considerable difficulties related both to the low level of impregnation achieved, due to the high viscosity of the resin, and to the filtration effects of the dispersed nanocharges. To overcome these problems, an opportunely modified process based on a sort of film infusion has been proposed. This modification has given an acceptable result in terms of impregnation and morphological arrangement of CNTs in nanofilled CFRP. Finally, the developed infiltration technique has been tested for the manufacture of a carbon fiber-reinforced panel with a more complex shape.

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Experimental torsional shear properties of carbon fiber reinforced epoxy composites containing carbon nanotubes

Composite Structures ◽

10.1016/j.compstruct.2013.04.033 ◽

2013 ◽

Vol 104 ◽

pp. 230-238 ◽

Cited By ~ 29

Author(s):

Naveed A. Siddiqui ◽

Shafi Ullah Khan ◽

Jang-Kyo Kim

Keyword(s):

Carbon Nanotubes ◽

Carbon Fiber ◽

Epoxy Composites ◽

Fiber Reinforced ◽

Shear Properties ◽

Torsional Shear ◽

Carbon Fiber Reinforced

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Contribution of carbon nanotubes to vibration damping behavior of epoxy and its carbon fiber composites

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684420906609 ◽

2020 ◽

Vol 39 (7-8) ◽

pp. 311-323

Author(s):

Esma Avil ◽

Ferhat Kadioglu ◽

Cevdet Kaynak

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Carbon Fiber ◽

Damping Ratio ◽

Vibration Damping ◽

Matrix Composites ◽

Fiber Reinforced ◽

Damping Behavior ◽

Continuous Carbon Fiber ◽

Carbon Fiber Reinforced

The main objective of this study was to investigate contribution of the non-functionalized multi-walled carbon nanotubes on the vibration damping behavior of first neat epoxy resin and then unidirectional and bidirectional continuous carbon fiber reinforced epoxy matrix composites. Epoxy/carbon nanotubes nanocomposites were produced by ultrasonic solution mixing method, while the continuous carbon fiber reinforced composite laminates were obtained via resin-infusion technique. Vibration analysis data of the specimens were evaluated by half-power bandwidth method; and the mechanical properties of the specimens were determined with three-point bending flexural tests, including morphological analyses under scanning electron microscopy. It was generally concluded that when even only 0.1 wt% carbon nanotubes were incorporated into neat epoxy resin, they have contributed not only to the mechanical properties (flexural strength and modulus), but also to the vibration behavior (damping ratio) of the epoxy. When 0.1 or 0.5 wt% carbon nanotubes were incorporated into continuous carbon fiber reinforced epoxy matrix composites, although they have no additional contribution to the mechanical properties, their contribution in terms of damping ratio of the composites were significant.

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Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420719873122 ◽

2019 ◽

Vol 234 (1) ◽

pp. 48-64 ◽

Cited By ~ 2

Author(s):

UA Khashaba ◽

Ramzi Othman ◽

IMR Najjar

Keyword(s):

Carbon Nanotubes ◽

Carbon Fiber ◽

Multiwalled Carbon Nanotubes ◽

Adhesive Joints ◽

Impact Loads ◽

Fiber Reinforced ◽

Multiwalled Carbon ◽

Impact Tests ◽

Carbon Fiber Reinforced ◽

The Impact

Scarf adhesive joints have attracted an increasing attention in joining/repairing of carbon fiber reinforced epoxy composite structures due to their zero eccentricity, which provides lower stress distribution across the adhesive layer and better aerodynamic surfaces compared to other bonded joints. The main objective of this study is to evaluate the performance of the scarf adhesive joints in carbon fiber reinforced epoxy composites under thermomechanical impact loads, which is very important for the aerospace and automotive industries. The adhesive was modified with optimum percentage of multiwalled carbon nanotubes. The impact tests were performed at 25 ℃, 50 ℃, and 75 ℃. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at 25 ℃, 50 ℃, and 75 ℃ showed improvement in the impact bending stiffness of the modified scarf adhesive joints by 8.3%, 7.4%, and 11.8% and maximum contact force by 15.6%, 21.3%, and 18.9%, respectively. The energy at failure of the modified scarf adhesive joints with multiwalled carbon nanotubes was improved by 15.2% and 16.4% respectively at 25 ℃ and 50 ℃. At test temperature of 75 ℃, the scarf adhesive joints have hysteresis load–displacement behavior and energy–time curve with rebound energy of 35% and absorbed (damage) energy of 65%. The residual flexural strength of the modified and unmodified scarf adhesive joints is 98.2% and 86.1% respectively, while their residual moduli have remarkable decrease to 71.7% and 81.3%.

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