Rheological Behaviors of Carbonaceous Materials Suspended in Sodium Alginate Solutions

2014 ◽  
Vol 906 ◽  
pp. 232-237 ◽  
Author(s):  
Hai Xiang Liu ◽  
Ye Qiang Tan ◽  
Qing Xu Zhang ◽  
Xue Qin ◽  
Ran Ran Zheng ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Loss Modulus ◽  
Chemical Properties ◽  
Complex Viscosity ◽  
Carbonaceous Materials ◽  
Rheological Measurement ◽  
Rheological Behaviors ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
And Chemical Properties

Three kinds of carbonaceous materials with different structural and chemical properties, Carbon Black (CB), Multi-walled Carbon Nanotubes (MWNTs), and Graphene Oxide (GO), were well suspended in sodium alginate (SA) solutions, and the suspension rheological behaviors were investigated in details. Steady rheological results showed that the suspensions exhibited same shear-thinning behaviors as SA solution. Dynamic rheological results showed that the complex viscosity (η*) was similar to that of steady rheological measurement, and both SA solution and SA/carbonaceous materials suspensions exhibited liquid-like behaviors, confirmed by the loss modulus larger than the storage modulus. The loss factor tanδremarkably decreased for SA/GO solution compared with SA/CB and SA/MWNTs suspension at the same concentration, indicating the increase of elasticity via interactions between the GO and SA.

Morphology Origin of Gradually Weakened Thermal-Conductivity Enhancement for HDPE/MWCNTs Nanocomposites

2016 ◽  
Author(s):  
Xiao-Hong Yin ◽  
Can Yang ◽  
Shiju E ◽  
Xiping Li ◽  
Jianbo Cao
Keyword(s):  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Loss Modulus ◽  
Low Frequency ◽  
Complex Viscosity ◽  
Thermal Conductivity Enhancement ◽  
Mwcnt Content ◽  
Conductivity Enhancement ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this work, high-density polyethylene/multi-walled carbon nanotubes (HDPE/MWCNTs) nanocomposites containing various filler loadings (i.e., 0.5∼16.0 wt.%) were prepared with their thermal conductivities determined using a laser-based analyzer. It was found that although the nanocomposite’s thermal conductivity increased with elevated MWCNT content, the enhancement degree lowered gradually. Rheology and microstructure characterizations were performed to reveal the morphology origin of gradually weakened thermal-conductivity enhancement. The dynamic rheology measurements showed that all nanocomposites exhibited higher storage modulus (G′), loss modulus (G″) as well as complex viscosity (η*) compared with the neat HDPE. More interestingly, the plateau of the flow regime formed at low frequency ranges with MWCNT loadings higher than 2.0 wt.% suggested the formation of the MWNCT network structures within the nanocomposites. The existence of such structures was further verified by the Cole-Cole curves obtained from the rheology testing and MWCNT distribution states from scanning electron microscope (SEM) results. The formation of MWCNT network lowered the degree of thermal-conductivity enhancement in such a way that it gave a larger possibility for MWCNTs to agglomerate, which led to phonon scattering that reduced the nanocomposite’s thermal conductivity.

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.

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.

scholarly journals Immobilization of Anammox biomass in sodium alginate

2018 ◽  
Vol 44 ◽  
pp. 00008 ◽  
Author(s):  
Anna Banach ◽  
Aneta Pudlo ◽  
Aleksandra Ziembińska-Buczyńska
Keyword(s):  
Sodium Alginate ◽  
Wastewater Treatment Plants ◽  
Chemical Properties ◽  
Anammox Bacteria ◽  
Ammonium Oxidation ◽  
Promising Technique ◽  
Nitrogen Gas ◽  
Slow Growth Rate ◽  
Anammox Activity ◽  
And Chemical Properties

Anaerobic ammonium oxidation (anammox) is a process of ammonium and nitrite conversion into nitrogen gas. Nowadays, anammox is applied into many wastewater treatment plants worldwide. However, anammox bacteria are characterized by a slow growth rate, which may cause problems in maintaining the biomass in the system. The promising technique which can help to maintain the biomass in the reactor and effectively prevent loss of anammox bacteria from a system is immobilization. Selection and optimization of the appropriate immobilization technique for investigated biomass is crucial for conducting an effective process. One of the ways for bacteria immobilization is gel entrapment. The main goal of the study was to test sodium alginate as an immobilization medium for anammox biomass. In the present study procedure of immobilization in sodium alginate was optimised, then the mechanical and chemical properties of the obtained pellets were investigated. Series of batch experiments revealed that immobilized anammox biomass was able to remove ammonia and nitrite nitrogen effectively. The calculated specific anammox activity (SAA) for immobilized anammox biomass was 0.18 g N·gVSS-1·d-1, while for non-immobilized biomass was 0.36 g N·gVSS-1·d-1.

Dynamic Rheological Behaviors of the Bone Scaffold Reinforced by Chitin Fibres

2005 ◽  
Vol 475-479 ◽  
pp. 2387-2390 ◽  
Author(s):  
X.M. Li ◽  
Qing Ling Feng
Keyword(s):  
Viscoelastic Properties ◽  
Loss Factor ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Materials Processing ◽  
Bone Scaffold ◽  
Rheological Behaviors ◽  
Wide Range ◽  
Yielding Behavior

In this study, a novel bioabsorbable porous bone scaffold reinforced by chitin fibres was prepared, the porosity of which is about 90 % and the pore size is approximately 200µm. The Advanced Rheological Enlarged System (ARES) was used to study the dynamic rheological behaviors of the ropy materials which would be made into the reinforced scaffold. The increase of the fibres’ volume content (Cf) enhanced the complex modulus (G*) and complex viscosity (h*) of the materials, the reason of which is that the fibres formed networks in the materials. When Cf increased from 35 % to 45 %, the storage modulus (G’) and loss modulus (G’’) curve showed obvious yielding behavior, which indicates that G’ and G’’ of the materials are hardly variable in a wide range. When Cf was more than 35 %, the loss factor (tand) was obviously lower than 1 and the materials exhibited viscoelastic properties, which result in a disadvantage for materials’ processing.

Removal of Cr(VI) from Aqueous Solutions Using PVA/SA Blend Films

2013 ◽  
Vol 781-784 ◽  
pp. 2142-2145
Author(s):  
Wen Juan Fan ◽  
Hong Xiang Ge ◽  
Yu Pang ◽  
Hui Chang
Keyword(s):  
Polyvinyl Alcohol ◽  
Sodium Alginate ◽  
Crosslinking Agent ◽  
Chemical Properties ◽  
Solution Ph ◽  
Hydrogen Bond Interaction ◽  
Blend Films ◽  
Molecular Force ◽  
Physical And Chemical ◽  
And Chemical Properties

The different ratios (PVA and SA) of PVA/SA blend films with cross-linking structure are successfully prepared by coagulating the mixture of sodium alginate (SA) and polyvinyl alcohol (PVA) in aqueous solution, then by treating with crosslinking agent CaCl2solution. The Surface morphology and flexibility of PVA/SA blend films were studied. The results indicate there is some strong interaction and good compatibility between sodium alginate and polyvinyl alcohol molecular. The physical and chemical properties of the PSA-80(PVA:SA=4:1) blend films are obviously improved owing to a molecular force and hydrogen bond interaction. The effects of parameters of the blend film was investigated in relation to its adsorption capability for low concentration ions Cr (VI) including such as SA content of the PVA/SA film, contact time, solution pH and temperature of solution. The results indicate that the maximum adsorption rate is 95.86% at the temperature 50°C under optimized pH 4 for 60min by PSA-80 films.

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.

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