scholarly journals Shear-Thickening Fluid Using Oxygen-Plasma-Modified Multi-Walled Carbon Nanotubes to Improve the Quasi-Static Stab Resistance of Kevlar Fabrics

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1356 ◽  
Author(s):  
Danyang Li ◽  
Rui Wang ◽  
Xing Liu ◽  
Shu Fang ◽  
Yanli Sun
Keyword(s):  
Carbon Nanotubes ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Woven Fabrics ◽  
Body Armor ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Stab Resistance ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The excellent mechanical property and light weight of protective materials are vital for practical application in body armor. In this study, O2-plasma-modified multi-walled carbon nanotubes (M-MWNTs) were introduced into shear-thickening fluid (STF)-impregnated Kevlar woven fabrics to increase the quasi-static stab resistance and decrease the composite weight. The rheological test showed that the addition of 0.06 wt. % M-MWNT caused a marked increase in the peak viscosity from 1563 to 3417 pa·s and a decrease in the critical shear rate from 14.68 s−1 to 2.53 s−1. The storage modulus (G′) and loss modulus (G″) showed a higher degree of abrupt increase with the increase of shear stress. The yarn pull-out test showed that the yarn friction of M-MWNT/STF/Kevlar fabrics was far superior to the original fabrics. Importantly, under similar areal density, the M-MWNT/STF/Kevlar fabrics could resist 1261.4 N quasi-static stab force and absorb 41.3 J energy, which were much higher than neat Kevlar fabrics. The results of this research indicated that quasi-static stab resistance was improved by M-MWNTs, which was attributed to the excellent shear-thickening effect and the high yarn friction. Therefore, M-MWNT/STF/Kevlar fabrics have a broad prospect in the fields of body protection.

Rheological response and quasi-static stab resistance of STF/MWCNTs-impregnated aramid fabrics with different textures

2019 ◽  
Vol 50 (3) ◽  
pp. 380-397
Author(s):  
Ting-Ting Li ◽  
Xixi Cen ◽  
Haokai Peng ◽  
Haitao Ren ◽  
Lianhe Han ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Shear Thickening ◽  
Critical Shear Rate ◽  
Shear Thickening Fluid ◽  
Aramid Fabric ◽  
Stab Resistance ◽  
Multi Walled Carbon Nanotubes ◽  
Aramid Fabrics ◽  
Self Protection ◽  
Walled Carbon Nanotubes

Terrorist attacks occur constantly, which subsequently arouses awareness of self-protection. In order to alleviate the harm caused by sharp objects of knives and daggers, a design of flexible stab-resistant materials that are impregnated with the shear thickening fluid (STF)/multi-walled carbon nanotubes (MWCNTs) system and different texture of fabrics is presented. STF/MWCNTs are composed of polyethylene glycol (PEG 200) as the dispersion medium and silica (SiO2) of 12 nm and 75 nm as disperse phase as well as MWCNTs as supplementary reinforcement, in expectation to provide the aramid fabrics with high strengths, low critical shear rate, and a short thickening response time. The textures of aramid fabrics—plain (P), twill (T), satin (S), or basket (B) weave—are saturated in the STF/MWCNTs system. The synergetic influences of silica size and texture on tensile strength, quasi-static knife, and spike stab resistances of the STF/MWCNTs-impregnated aramid fabrics are examined. Results show that the plain aramid fabric immersed in the STF/MWCNTs system containing 12 nm SiO2(SM12) exhibit the maximum tensile strength and quasi-static knife stab resistance, 14.7 MPa and 8.9 MPa, respectively, which is 1.15 and 1.43 times higher than pure aramid fabrics. Moreover, the basket-weave aramid fabric immersed in the STF/MWCNTs system containing 12 nm SiO2have the maximum quasi-static spike stab resistance of 17.12 MPa compared to other textures of fabrics, which is 1.05 times higher than those immersed in the 75 nm SiO2STF/MWCNTs (SM75) system and 1.33 times higher than that of pure basket aramid fabrics.

Characterization of Vinyl Ester/Jute Fiber Bio-Composites in the Presence of Multi-Walled Carbon Nanotubes

2017 ◽  
Vol 730 ◽  
pp. 221-225
Author(s):  
Mohamed Bassyouni ◽  
Shereen M.S. Abdel-Hamid ◽  
Mohamed H. Abdel-Aziz ◽  
M.Sh. Zoromba
Keyword(s):  
Carbon Nanotubes ◽  
Storage Modulus ◽  
Vinyl Ester ◽  
Loss Modulus ◽  
Weight Ratio ◽  
Mechanical Analysis ◽  
Jute Fiber ◽  
Multi Walled Carbon Nanotubes ◽  
Fiber Reinforcements ◽  
Walled Carbon Nanotubes

In this study, vinyl ester –Jute fiber biocomposites were prepared using vacuum-assisted resin infusion (VARI) process. Woven Jute fibers were used with mass fraction 0.68. Multi-walled carbon nanotubes (MWCNTs) are added to the resin with weight ratio 0.5: 99.5 to investigate the thermo-mechanical properties of bio-composites. Storage and loss modulus of vinyl ester bio-composites were investigated in the presence MWCNTs over a range of temperature (25 to 160 oC) to measure the capacity of bio-composite to store and dissipate energy. Damping properties of vinyl ester bio-composites were studied in terms of tan (d). Viscoelastic test using dynamic mechanical analysis (DMA) showed that the glass transition temperature increases with the addition of MWCNTs up to 112.4 oC. Addition of jute fiber reinforcements improves the storage modulus value of vinyl ester more than 65% at room temperature. Significant improvement in storage modulus was found in the presence of MWCNTs.

Mechanical properties of carbon nanotubes/epoxy nanocomposites: Pre-curing, curing temperature, and cooling rate

2021 ◽  
pp. 095400832199209
Author(s):  
Hermawan Judawisastra ◽  
Christian Harito ◽  
Dika Anindyajati ◽  
Hengky Purnama ◽  
Akbar Hanif Dawam Abdullah
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Cooling Rate ◽  
Resin Acid ◽  
Diglycidyl Ether ◽  
Curing Temperature ◽  
Pull Out ◽  
Multi Walled Carbon Nanotubes ◽  
Mechanical Properties Characterization ◽  
Walled Carbon Nanotubes

The effects of composite fabrication, such as pre-curing, curing temperature, and cooling rate, were studied. In this work, the pre-curing was defined as heat treatment of Multi-Walled Carbon Nanotubes (MWNCTs) with Diglycidyl Ether of Bisphenol A (DGEBA) epoxy resin. Acid purified MWCNTs were characterized by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The pre-curing facilitated bonding between MWCNTs and epoxy via the oxirane ring of DGEBA, which accelerated the curing process of epoxy and increased mechanical properties. The elevated curing temperature on the pre-cured sample further improved the composite’s mechanical properties by increasing interfacial bonding due to cross-linking. The rapid cooling using liquid nitrogen during pre-curing treatment prevented re-agglomeration of MWCNTs, showing smaller agglomerates and improving the mechanical properties. Agglomeration was characterized by scanning electron microscopy, while the bonding between MWCNTs and epoxy was examined by the length of fibre pull-out on the fracture surface. Tensile testing was deployed for mechanical properties characterization. The degree of cure was determined by FTIR and Differential Thermal Analysis (DTA).

Effect of multi-walled carbon nanotubes with different diameters on morphology and thermal and mechanical properties of flexible polyurethane foams

2021 ◽  
pp. 026248932110172
Author(s):  
Fukai Yang ◽  
Miao Xie ◽  
Zhang Yudi ◽  
Xinyu Xu
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
In Situ Polymerization ◽  
Loss Modulus ◽  
Polyurethane Foams ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Different Diameters ◽  
Flexible Polyurethane ◽  
Walled Carbon Nanotubes

We report flexible polyurethane foams (PUFs) containing –OH functionalized multi-walled carbon nanotubes (MWCNTs) with different diameters (10–20 nm, 20–30 nm, >50 nm) from 0.1–0.6 wt% (per 100 resins of polyol by weight) prepared via in situ polymerization. After synthesis, the morphology of the MWCNT/PUF composites was observed through scanning electron microscopy (SEM) based on MWCNT amount. The MWCNTs acted as nucleating agents and increased the matrix viscosity. The pore size of the composites decreased and the number of pores increased with increasing MWCNT concentration. Dynamic mechanical analysis (DMA) showed that the storage modulus of the composites increased, the loss modulus decreased, and the Tg gradually decreased with increasing MWCNT content. The incorporation of MWCNTs induced remarkable thermal stabilization of the matrix. The increase in the degradation temperature from 294°C to 304°C resulted in a 50% weight loss. The mechanical properties of the MWCNT/PUF materials increased with increasing MWCNT proportion because of the excellent compatibility and strong interface interaction between the MWCNT and flexible PUF.

Single-yarn pull-out test in neat, solvent-treated and shear-thickening fluid-impregnated Kevlar® KM2 fabric

2017 ◽  
Vol 8 (2) ◽  
pp. 154-178 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
S. Ramaswami
Keyword(s):  
Finite Element ◽  
Shear Thickening ◽  
Lagrangian Formulation ◽  
Body Armor ◽  
Computational Framework ◽  
Shear Thickening Fluid ◽  
Content Type ◽  
Pull Out ◽  
Single Yarn ◽  
Experimental Findings

Purpose In order to help explain experimental findings related to the stabbing- and ballistic-penetration resistance of flexible body-armor, single-yarn pull-out tests, involving specially prepared fabric-type test coupons, are often carried out. The purpose of this paper is to develop a finite-element-based computational framework for the simulation of the single-yarn pull-out test, and applied to the case of Kevlar® KM2 fabric. Design/methodology/approach Three conditions of the fabric are considered: neat, i.e, as-woven; polyethylene glycol (PEG)-infiltrated; and shear-thickening fluid (STF)-infiltrated. Due to differences in the three conditions of the fabric, the computational framework had to utilize three different finite-element formulations: standard Lagrangian formulation for the neat fabric; combined Eulerian-Lagrangian formulation for the PEG-infiltrated fabric (an Eulerian subdomain had to be used to treat the PEG solvent/dispersant); and combined continuum Lagrangian/discrete-particle formulation for the STF-infiltrated fabric (to account for the interactions of the particles suspended in PEG, which give rise to the STF character of the suspension, with the yarns, the particles had to be treated explicitly). Findings The results obtained for the single-yarn pull-out virtual tests are compared with the authors’ experimental counterparts, and a reasonably good agreement is obtained, for all three conditions of the fabric. Originality/value To the authors’ knowledge, the present work represents the first attempt to simulate single-yarn pull-out tests of Kevlar® KM2 fabric.

scholarly journals Rheological Properties and Flow Behaviour of Cement-Based Materials Modified by Carbon Nanotubes and Plasticising Admixtures

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 169
Author(s):  
Gintautas Skripkiunas ◽  
Ekaterina Karpova ◽  
Joana Bendoraitiene ◽  
Irmantas Barauskas
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Yield Stress ◽  
Cement Paste ◽  
Shear Thickening ◽  
Plastic Viscosity ◽  
Flow Behaviour ◽  
Volume Coefficient ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this study, the rheological properties of cement paste modified by a suspension containing both multi-walled carbon nanotubes (MWCNT) and carboxymethyl cellulose (CMC) (MWCNT/CMC suspension) with different types of plasticising admixtures (Pl), such as lignosulphonate (LS), sulfonated naphthalene formaldehyde condensate (NF), and polycarboxylate ether (PCE) were evaluated. The increase in yield stress and plastic viscosity up to 20% was established in the case of the modification of cement-based mixtures by MWCNT in the dosage up to 0.24% by weight of cement (bwoc) without Pl and with LS and NF. The complex modification of cement paste by MWCNT and PCE increases the yield stress and plastic viscosity from the MWCNT dosage of 0.06% and 0.015% bwoc, respectively. The yield stress and plastic viscosity of cement paste with PCE enhanced by 265% and 107%, respectively, in a MWCNT dosage of 0.12% bwoc. MWCNT do not have a significant influence on the flow behaviour index of cement paste; however, in the case of usage of PCE, the shear thickening effect decreased from a MWCNT dosage of 0.03% bwoc. The significant reduction in the volume coefficient of water bleeding by 99, 100, and 83% was obtained with LS, NF, and PCE, respectively, with an increase in MWCNT dosage up to 0.24% bwoc.

Effects of Multi-Walled Carbon Nanotubes on the Properties of Acrylonitrile Butadiene Styrene Nanocomposites Potentially Used for Fused Deposition Modeling

2017 ◽  
Vol 898 ◽  
pp. 2384-2391
Author(s):  
Jin Zhu ◽  
Biao Wang
Keyword(s):  
Carbon Nanotubes ◽  
Fused Deposition Modeling ◽  
Loss Modulus ◽  
Linear Thermal Expansion ◽  
Acrylonitrile Butadiene Styrene ◽  
Low Frequencies ◽  
Fused Deposition ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Butadiene Styrene

Multi-walled carbon nanotubes (MWCNTs)/acrylonitrile butadiene styrene (ABS) nanocomposites were prepared by melt blending and then filaments were obtained by melt extrusion method. The Scanning electron microscope (SEM) exhibited good dispersion of MWCNTs in the SAN phase of the ABS matrix. The rheological results showed that incorporation of MWCNTs into ABS resulted in higher storage modulus (G′) and loss modulus (G′′) than those of ABS, especially at low frequencies. The tensile strength and modulus of MWCNT/ABS nanocomposite filaments substantially increased with the MWCNTs content while the elongation at break decreased. Additionally, the addition of MWCNTs decreased the coefficient of linear thermal expansion. This study provides a basis for further development of MWCNT/ABS nanocomposites used for FDM process with desirable mechanical properties and good dimension stability.

scholarly journals Effect of particle size of fumed silica on the puncture resistance of fabrics impregnated with shear thickening fluid

2021 ◽  
Vol 16 ◽  
pp. 155892502110613
Author(s):  
Zhenqian Lu ◽  
Zishun Yuan ◽  
Jiawen Qiu
Keyword(s):  
Particle Size ◽  
Fumed Silica ◽  
Shear Thickening ◽  
Weight Fraction ◽  
Areal Density ◽  
Woven Fabrics ◽  
Body Armor ◽  
Shear Thickening Fluid ◽  
Puncture Resistance ◽  
Effect Of Particle Size

This paper presents an investigation into the effect of particle size of fumed silica on the puncture resistance of fabric impregnated with shear thickening fluid (STF). Two different types of STF were fabricated from fumed silica nanoparticles with particle sizes of 12 and 40 nm respectively. The effects of the particle size and weight fraction of the fumed silica on the rheological property were studied. STFs impregnated woven fabrics were fabricated and tested for stabbing resistance. STFs made of fumed silica with large particle size have better shear thickening effect. The stabbing resistant performance of STF impregnated fabrics improved notably with the same number of layers of fabric, and STFs impregnated fabric panels also outperform the untreated fabric panels with the same areal density. The results indicated that STFs made of fumed silica with larger particle size is able to fabricate a lighter soft body armor with higher stabbing protection.

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