Improving mechanical properties of epoxy by adding multi-wall carbon nanotube

Fadhil, Basim M.; Ahmed, Payman Sahbah; Kamal, Ava Ali

doi:10.15632/jtam-pl.54.2.551

Cited by 10 publications

(9 citation statements)

References 16 publications

(12 reference statements)

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“…Fibrillation was hardly observed in AF/PAE/L4. This is attributed to the fact that the MWCNTs-COOH form a network structure on the fiber surface, and when the apply loading is over the elastic deformation stress, the MWCNTs-COOH transfer the stress . During the puncture test, this network structure acted as a protective layer to increase the fiber resistance to the impact load.…”

Section: Resultsmentioning

confidence: 99%

“…This is attributed to the fact that the MWCNTs-COOH form a network structure on the fiber surface, and when the apply loading is over the elastic deformation stress, the MWCNTs-COOH transfer the stress. 37 During the puncture test, this network structure acted as a protective layer to increase the fiber resistance to the impact load. L-MWCNTs-COOH were interlaced with each other; thus, they were more conducive to uniformly dispersing and transferring stress.…”

Section: Resultsmentioning

confidence: 99%

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Polyacrylate and Carboxylic Multi-Walled Carbon Nanotube-Strengthened Aramid Fabrics as Flexible Puncture-Resistant Composites for Anti-Stabbing Applications

Cai

Zhang

2023

ACS Appl. Nano Mater.

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Lightweight and soft puncture-resistant fabrics have great applications in professional clothing. A soft composite fabric was fabricated by coating a water-soluble polyacrylate emulsion (PAE) on the surface of aramid fabric (AF; AF/PAE). The areal weight of AF/PAE fabric was only 7.1% higher than that of AF ones. Under spike stabbing, both the maximum load and energy absorption capacity of AF/PAE were about 4.5 times higher than those of AF. The puncture resistance of AF/PAE was superior to those of shear thickening fluid (STF)-impregnated AF (AF/STF) and polyurethane (PU)-sprayed AF (AF/PU) under the same areal weight or thickness. Carboxylic multi-walled carbon nanotubes (MWCNTs-COOH; 0.4 wt %) were then added to AF/PAE to further enhance the puncture resistance of the composite fabric. The spike punching resistance of AF/PAE increased by about 49.2% after the addition of MWCNTs-COOH. MWCNTs-COOH created a bridge effect between fibers to enhance friction between yarns. In addition, MWCNTs-COOH on the fiber surface can form a network protective membrane, which can effectively disperse stress and reduce fiber fibrillation, thus improving the puncture resistance of the fabric. This study provides an efficient method for the development of lightweight and flexible anti-stabbing equipment.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Polyacrylate and Carboxylic Multi-Walled Carbon Nanotube-Strengthened Aramid Fabrics as Flexible Puncture-Resistant Composites for Anti-Stabbing Applications

Cai

Zhang

2023

ACS Appl. Nano Mater.

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“…It had been noted that the nanocomposites and the neat composites showed better performance than the Al plates, but lesser bumper shields (Khatiwada et al, 2013). Fadhil et al (2016) utilized weight percentages (0, 0.2, 0.4, 0.6, 0.8, 1) Wt.% of multi-walled carbon nanotubes (MWCNTs) to reinforce epoxy resin. Mechanical properties of the composites were assessed by tensile and drop-weight impact tests.…”

Section: Mmms 166mentioning

confidence: 99%

“…Mechanical properties of the composites were assessed by tensile and drop-weight impact tests. The results revealed that 0.2 Wt.% of MWCNTs improve tensile properties, whereas 0.6 Wt.% of MWCNTs improve impact characteristics (Fadhil et al, 2016). Ahmed (2016) used different designs of the impactor in drop-weight impact test (bullet, cone and hemispherical) and investigated this effect on the impact properties of epoxy composites reinforced with unidirectional glass, unidirectional carbon, woven glass and hybrid woven (glass þ carbon) fibers.…”

Section: Mmms 166mentioning

confidence: 99%

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Abed

Ahmed

Oleiwi

et al. 2020

MMMS

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PurposeComposite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a comparison of composites 12 and 20 layers of fabrics Kevlar and ultrahigh-molecular-weight poly ethylene (UHMWPE)-reinforced epoxy under low-velocity impacts represented by drop-weight impact and Izod pendulum impact has been done. During the Izod test, Kevlar-based composite showed damage at the composite center and fiber breakages. Whereas delamination was observed for UHMWPE reinforced epoxy (PE). The maximum impact strength was for Kevlar-reinforced epoxy (KE) and increases with the number of laminates. Drop-weight impact test showed the highest absorbed energy for (KE) composites. The results revealed that different behavior during the impact test for composites belongs to the impact mechanism in each test.Design/methodology/approachAramid 1414 Kevlar 49 and UHMWPE woven fabrics were purchased from Yixing Huaheng High-Performance Fiber Textile Co. Ltd, with specifications listed in Table 1. Epoxy resin (Sikafloor-156) is supplied from Sika AG. Sikafloor-156 is a two-part, low-viscosity, solvent-free epoxy resin, with compressive strength ∼95 N/mm², flexural strength ∼30 N/mm² and shore D hardness 83 (seven days). The mixture ratio of A/B was one-third volume ratio. Two types of laminated composites with different layers 12 and 20 were prepared by hand layup: Kevlar–epoxy and UHMWPE–epoxy composites as shown in Figure 1. Mechanical pressure was applied to remove bubbles and excess resin for 24 h. The composites were left in room temperature for seven days, and then composite plates were cut for the desired dimensions. Low-velocity impact testing, drop-weight impact, drop tower impact system INSTRON CEAST 9350 (see Figure 2) was facilitated to investigate impact resistance of composites according to ASTM D7137M (Test Method for Compressive, 2005). Low-velocity impact tests have been performed at room temperature for composite with dimensions 10 × 15 cm2 utilizing a drop tower (steel indenter diameter 19.85 mm as shown in Figure 3), height (800 mm), drop mass (5 kg) and speed (3.96 m/s). Special impact equipment consisting of vertically falling impactor was used in the test. The energy is obtained from Drop tower impact systems, (2009) E = ½ mv2 (2.1). The relationship between force–time, deformation–time and energy–time and deformation was obtained. Energy–deformation and force–deformation relationships were also obtained. The depth of penetration and the radius of impactor traces were recorded. Izod pendulum impact test of plastics was applied according to ASTM D256 (Test Method for Compressive, 2005). Absorbed energy was recorded to compute the impact strength of the specimen. The specimen before the test is shown in Figure 4.FindingsIn order to investigate two types of impact: drop-weight impact and Izod impact on damage resistance of composites, the two tests were done. Drop-weight impact is dropping a known weight and height in a vertical direction with free fall, absorbed energy can be calculated. Izod impact measures the energy required to break a specimen by striking a specific size bar with a pendulum (Test Method for Compressive, 2005; Test Methods for Determining, 2018). The results obtained with the impact test are presented. Figure 5 shows the histogram bars of impact strength of composites. It can be noticed that Kevlar–epoxy (KE) composites give higher energy strength than UHMWPE–epoxy (PE) in 12 and 20 plies. The increasing percentage is about 18.5 and 5.7%. It can be observed in Figure 6 that samples are not destructed completely due to fiber continuity. Also, the delamination occurs obviously for UHMWPE–epoxy more than for Kevlar-based composite, which may due to weak binding between UHMWPE with an epoxy relative with Kevlar.Practical implicationsThe force–time curves for Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites with 12 and 20 plies are illustrated respectively in Figure 7. The contact duration between indenter and composite surface is repented by the force–time curves, so the maximum force reaches with certain displacement. It can be seen that maximum force was (13,209, 18,734.9, 23,271.07 and 19,825.38 N) at the time (3.97, 4.43, 3.791 and 4.198 ms) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. The sharp peaks of KE composite are due to the lower ductility of Kevlar compared with UHMWPE. These results agree with the results of Ahmed et al. (2016). Kevlar-based composites (KE) showed lower impact force and crack propagates in the matrix with fast fiber breakage compared with PE composites, whereas the latter did not suffer from fabric breakage in 12 and 20 plies any more (see Figure 8). Figure 9 illustrates force–deformation curves, for 12 and 20 plies of Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites. Curve's slop is considered the specimen's stiffness and the maximum displacement. To investigate the impact behavior of the four different composites, the comparison was made among the relative force–deformation curves. The maximum displacement was 5.119, 3.443, 1.173 and 1.17 mm for 12KE, 12 PE, 20 KE and 20 PE, respectively. It seems that UHMWPE-based composite (PE) presents lower deformation than Kevlar-based composites (KE) at a same number of laminates, although the maximum displacement is for 12 PE and 12 KE (see Figure 8). Kevlar-based composites (KE) showed more damage than UHMWPE-based composite (PE), so the maximum displacement is always higher for KE specimens with maximum indenter trace diameter (D∼11.27 mm). The onset of cracks begins along fibers on the impacted side for 20 KE and 20 PE specimens with lower indenter trace (D∼5.42 and 5.96 mm), respectively (see Table 2). These results refer to the lower stiffness of KE composites (see the slope of the curve) relative to PE composites. This result agreed with (Vieille et al., 2013) when they found that the theoretical stiffness of laminated composite during drop-weight impact depends significantly on fiber nature (Fadhil, 2013). The matrix cracking is the first type of damage that may not change stiffness of composites overall. Material stiffness changes due to the stress concentration represented by matrix cracks, delamination and fiber breakage (Hancox, 2000). Briefly, the histogram (see Figure 10) showed that the best impact behavior was for 20 KE, highest impact force with lower deformation, indenter trace diameter and contact time. Absorbed energy–time and absorbed energy–deformation curves for composites are shown in Figures 11 and 12, respectively. The maximum absorbed energy was (36.313, 29.952, 9.783 and 6.928 J) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. Test period time is only 8 ms, but the time in which composites reached maximum absorbed energy was (4.413, 3.636, 2.394 and 2.408 ms). The maximum absorbed energy was for 12 KE with lower rebound energy because part of kinetic energy transferred to potential energy kept in the composite as material damage (see Figures 3 and 4). This composite absorbs more energy as material damage which kept as potential energy. Whereas other composites 12 PE, 20 PE and 20 KE showed less damage, lower absorbed energy and higher rebound energy, which appeared in different peak behavior as the negative value of energy. Also from the absorbed energy–time curves, it had been noticed significantly the maximum contact time of indenter with composite was 4.413 ms for 12 KE, which exhibits higher deformation (5.119 mm), whereas other composites 12 PE, 20 KE and 20 PE showed less damage, contact time and deformation as (3.443, 1.173, 1.17 mm), respectively.Originality/valueThe main goal of the current study is to evaluate the performances of armor composite made off of Kevlar and UHMWPE fabrics reinforced epoxy thermosetting resin under the low-velocity impact. Several plates of composites were prepared by hand layup. Izod and drop-weight impact tests were facilitated to get an indication about the absorbed energy and strength of the armors.

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“…Tensile and drop weight impact test are used to evaluate the mechanical properties of the composites. Results shows that adding 0.2 wt.% of MWCNTs enhance and increase the tensile properties and Adding 0.6 wt.% of MWCNTs enhance the impact properties [3]. Impact characteristics of epoxy matrix composites have been studied by Payman S. A. et.…”

Section: Introductionmentioning

confidence: 99%

Effect of reinforcement material on impact properties of epoxy

Fadhil

Ahmed

Kamal

2017

KJAR

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Impact characteristics of Epoxy matrix composites is investigated by impact machine. Four different types of reinforcement are used in the experimental works: type one: 1.9wt% steel fiber, 1.9wt% carbon fiber,1.9 wt% carbon nanotube, 1.9 wt% woven carbon fiber. This work shows that reinforcing epoxy with (1.9 wt% of woven carbon fiber) improves the impact properties where energy, force and deformation values of impact test for this composite were 18.4J, 3580.59 N and 18 mm respectively while for epoxy were 2.927 J, 921.849 N and 18.413 mm respectively.

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Improving mechanical properties of epoxy by adding multi-wall carbon nanotube

Cited by 10 publications

References 16 publications

Polyacrylate and Carboxylic Multi-Walled Carbon Nanotube-Strengthened Aramid Fabrics as Flexible Puncture-Resistant Composites for Anti-Stabbing Applications

Polyacrylate and Carboxylic Multi-Walled Carbon Nanotube-Strengthened Aramid Fabrics as Flexible Puncture-Resistant Composites for Anti-Stabbing Applications

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Effect of reinforcement material on impact properties of epoxy

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