Investigation of effects of extreme environment conditions on multiwall carbon nanotube‐epoxy adhesive and adhesive joints

Abstract

Mechanical and thermal properties of epoxy‐multiwall carbon nanotubes (MWCNTs) at different fractions (0.0, 0.25, 0.5, and 1.0 wt%) were investigated. The dispersion of the nanotubes in an epoxy adhesive commonly used in an automotive application was performed using a grease worker. This device has a perforated plate, able to produce mechanical shear. To investigate the behavior of adhesive‐carbon nanotubes mixtures and the bonding performance, four groups were prepared using two different perforated plates, P1 and P2. All MWCNT‐epoxy were submitted to extreme environmental conditions, resumed as reference (non‐aged), 500 h at 100°C, 500 h at 95% of relative humidity at 40°C, and 500 h under salt spray. A reduction in glass transition temperature was observed with the addition of the nanofiller and no increases on statistic heat‐resistant index temperature were noticed in MWCNT‐epoxy produced using both plates. Changes in the peaks at 3300, 1510, and 835 cm−1 after aging were seen in infrared spectra. The MWCNT addition to pure epoxy increased the apparent shear strength by 14% using P1. In P2, which has the mechanical shear greater by a factor of 2, no significant differences were observed, due to defects and agglomeration of MWCNTs observed by image analysis.

Ultimate tensile behavior of short single‐wall carbon nanotube/epoxy composites and the reinforced mechanism

“…However, the optimal CNT content φ opt strongly depends on the radius r and increases from $0.4 wt% for r = 2 nm to $25 wt% for r = 20 nm. In fact, from Equation (11), the dependence of optimal CNT length on CNT content and that of optimal CNT content on CNT radius can be also obtained, as shown in Figure 8. It can be seen that the optimal CNT length decreases with the CNT content and increases with the CNT radius (Figure 8A).…”

“…[5] In the past few decades, CNTs were used to reinforce epoxy and enhance its electrical and thermal conductivity. [6,7] For example, addition of 0.05-1.0 wt% multiwall carbon nanotubes (MWCNTs) into epoxy can increase the tensile, flexural and shear strength of composites obviously, [8][9][10][11] usually a strength increase of >20% can be obtained for an optimal MWCNT content. Meanwhile, addition of MWCNTs into epoxy can greatly enhance the impact and damping performance of composites, [12][13][14] and 0.5 wt% MWCNTs can increase the impact strength of composites up to $40%, [12] where the sizes of CNTs are an influence factor.…”

Design of Adhesive Bonded Joints

“…Structural adhesives, with tailored properties to meet specific application requirements, as identified in the previous section, are a focal point of ongoing investigations [26]. Experimental testing of adhesives under extreme conditions, such as high temperatures or corrosive environments, provides insights into the limits of adhesive performance [27,28]. Numerical analyses, including FEM simulations, are becoming more sophisticated.…”

Enhancing shear and flexural strength of single lap composite joints with a graphene nanoparticle‐reinforced adhesive through a co‐curing technique

“…Utilizing a structural adhesive for joining composite components is a more advanced approach, as it yields an enhanced distribution of stress throughout the entire joint. [11][12][13] The use of adhesive bonding can be considered the best technique for the bonding of different components within marine and aviation structures. This technique enables a combination of other materials, thereby achieving the desired levels of strength and flexibility that correspond with the adhesive's specific features.…”

“…These properties are especially effective in industries focusing on lightweight structures, such as aviation, aerospace, and automotive applications. Utilizing a structural adhesive for joining composite components is a more advanced approach, as it yields an enhanced distribution of stress throughout the entire joint 11–13 . The use of adhesive bonding can be considered the best technique for the bonding of different components within marine and aviation structures.…”