scholarly journals Antimicrobial Properties of Chitosan-Alumina/f-MWCNT Nanocomposites

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Monaheng Masheane ◽  
Lebea Nthunya ◽  
Soraya Malinga ◽  
Edward Nxumalo ◽  
Tobias Barnard ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Polymer Matrix ◽  
Antimicrobial Properties ◽  
Inversion Method ◽  
Bacterial Strains ◽  
Multiwalled Carbon ◽  
Simple Phase ◽  
Phase Inversion Method ◽  
Thermal Stability Of ◽  
Sem Analyses

Antimicrobial chitosan-alumina/functionalized-multiwalled carbon nanotube (f-MWCNT) nanocomposites were prepared by a simple phase inversion method. Scanning electron microscopy (SEM) analyses showed the change in the internal morphology of the composites and energy dispersive spectroscopy (EDS) confirmed the presence of alumina and f-MWCNTs in the chitosan polymer matrix. Fourier transform infrared (FTIR) spectroscopy showed the appearance of new functional groups from both alumina and f-MWCNTs, and thermogravimetric analysis (TGA) revealed that the addition of alumina and f-MWCNTs improved the thermal stability of the chitosan polymer. The presence of alumina and f-MWCNTs in the polymer matrix was found to improve the thermal stability and reduced the solubility of chitosan polymer. The prepared chitosan-alumina/f-MWCNT nanocomposites showed inhibition of twelve strains of bacterial strains that were tested. Thus, the nanocomposites show a potential for use as a biocide in water treatment for the removal of bacteria at different environmental conditions.

scholarly journals Synthesis, Characterization and Their Antimicrobial Activities of Boron Oxide/Poly(Acrylic Acid) Nanocomposites: Thermal and Antimicrobial Properties

2018 ◽  
Vol 18 (1) ◽  
pp. 28-36 ◽  
Author(s):  
P. T. Beyli ◽  
M. Doğan ◽  
Z. Gündüz ◽  
M. Alkan ◽  
Y. Turhan
Keyword(s):  
Thermal Stability ◽  
Acrylic Acid ◽  
Polymer Matrix ◽  
Boron Oxide ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Dilution Method ◽  
Solution Intercalation ◽  
Thermal Stability Of ◽  
Poly Acrylic Acid

AbstractBoron oxide (B2O3)/Poly(acrylic acid) (PAA) nanocomposites were synthesized by solution intercalation method, and characterized by Fourier transform infrared spectroscopy (FTIR-ATR), transmission electron microscopy (TEM), X-ray diffraction and thermogravimetric analysis (DTA/TG). The effect of boron oxide amount on the thermal stability of nanocomposites was investigated. Moreover, the antimicrobial activities of them were also determined by the serial dilution method against E. coli and S. aureus. XRD analysis showed that boron oxide was homogenously dispersed in polymer matrix; FTIR-ATR that there was interaction between PAA and boron oxide; and TEM that boron oxide particles had spherical structure, and dispersed in nano size in polymer matrix; DTA/TG that the thermal stability of polymers increased with the adding of boron oxide into polymer matrix, and changed the decomposition mechanism of PAA. B2O3/PAA nanocomposites exhibited higher decomposition temperature. The decomposition mechanisms of PAA and its nanocomposites occurred through three decomposition steps; dehydration, decarboxylation and chain scission. B2O3/PAA nanocomposites showed greater antimicrobial activity with increasing B2O3 amount.

An effective and novel approach for enhancement of the oxidative thermal stability of multiwalled carbon nanotubes loaded polymer blend

2019 ◽  
Vol 33 (11) ◽  
pp. 1499-1517
Author(s):  
Mohammad Abu-Abdeen ◽  
Osama Saber ◽  
Javed Mazher ◽  
Mohamed M Ahmed ◽  
Mohamed Gouda
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Thermal Treatment ◽  
Multiwalled Carbon Nanotubes ◽  
Polymer Matrix ◽  
Gravimetric Analysis ◽  
Multiwalled Carbon ◽  
Ac Electrical Conductivity ◽  
Wide Range ◽  
Thermal Stability Of

Multiwalled carbon nanotubes (MWCNTs) have wide range of applications. Commercial MWCNTs have impurities, disorder and entangled structure, which limit its applications. In this respect, novel, low-energy consumption and friendly technique was applied to enhance its structure. The technique is operated during isometric process inside autoclave and based on thermal treatment of MWCNTs in the presence of solvent and pressure. It was used to enhance the oxidative thermal stability of MWCNTs. Thermal gravimetric analysis results showed an increase in onset temperature, activation energy of decomposition, and the temperature required to loss 75, 50, and 33 wt% as the treating temperature increased. Raman spectroscopy tests showed a decrease in the degree of disorder from 1.29 for untreated samples to 0.45 for samples treated at 250°C. The electrical resistivity of MWCNTs was increased from 0.33 Ω.cm for untreated samples to 0.54 Ω cm for 250°C treated samples. Advantages of thermal treatment of MWCNTs using this technique appeared in the presence of a percolation behavior for the AC electrical conductivity when a polymer matrix was loaded with it with a threshold percolation concentration of 0.7 wt%. Furthermore, Cole–Cole Z semicircles as well as Argand plots of the electric modulus appeared for polymer matrix loaded with thermally treated MWCNTs beyond the threshold percolation concentration.

Effect of the hydrophilicity of the polymer matrix on immobilized α-chymotrypsin

1984 ◽  
Vol 49 (6) ◽  
pp. 1552-1556
Author(s):  
Minoru Kumakura ◽  
Isso Kaetsu
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Pore Size ◽  
Polymer Matrix ◽  
Low Temperatures ◽  
Radiation Polymerization ◽  
Thermal Stability Of

α-Chymotrypsin was immobilized by radiation polymerization at low temperatures and the effect of the hydrophilicity of the polymer matrix on the enzyme activity and thermal stability was studied. The activity and thermal stability of immobilized chymotrypsin increased with the increasing hydrophilicity of the polymer matrix or monomer. The thermal stability was affected by the form and pore size of the polymer matrix; chymotrypsin immobilized on a soft-gel polymer matrix exhibited an enhanced thermal stability.

scholarly journals Effects of Current on Arc Fabrication of Cu Nanoparticles

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
M. Z. Kassaee ◽  
F. Buazar ◽  
E. Motamedi
Keyword(s):  
Thermal Stability ◽  
Distilled Water ◽  
Face Centered Cubic ◽  
Cu Nanoparticles ◽  
Dta Analysis ◽  
Face Centered ◽  
Average Size ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Sem Analyses

Arc-fabricated copper nanoparticles (Cu Nps) size, morphology and the crystalline structure, as well as the yields of Nps appear sensitive to the applied currents (50–160 A) in distilled water. The results indicate that the sizes of Cu Nps are directly proportional to the currents employed. At 50 A, TEM, XRD, and SEM analyses show fabrication of relatively purest, the most dispersed, face-centered cubic (fcc) brown Cu Nps with rather smallest average size of 20 nm. At the same current, the TGA-DTA analysis reveals neither weight loss nor gain, indicating thermal stability of the fabricated Cu Nps.

Thermal and viscoelastic behaviors of nanotube-reinforced polyethylene composite

2011 ◽  
Vol 1312 ◽  
Author(s):  
Ananta Raj Adhikari ◽  
Mircea Chipara ◽  
Karen Lozano
Keyword(s):  
Mechanical Property ◽  
Thermal Stability ◽  
Mechanical Behavior ◽  
Storage Modulus ◽  
Polymer Matrix ◽  
Loss Modulus ◽  
Polyethylene Composite ◽  
Viscoelastic Behaviors ◽  
Thermal Stability Of

ABSTRACTThe effect of processing (shear) time on the mechanical behavior and thermal stability of multiwalled nanotube reinforced polyethylene was investigated. It was observed that the mechanical property (storage modulus, loss modulus) of the composites is process dependant whereas the thermal stability does not. The increase in mechanical behavior is attributed to a stronger interface between the nanotube and the polymer matrix.

scholarly journals Effect of Nanodiamond Particles on Properties of Epoxy Composites

2008 ◽  
Vol 17 (1) ◽  
pp. 096369350801700 ◽  
Author(s):  
Zdeno Špitalský ◽  
Alexander Kromka ◽  
Libor Matějka ◽  
Peter Černoch ◽  
Jana Kovářová ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Epoxy Composites ◽  
Neat Epoxy ◽  
Light Transmittance ◽  
Cross Linking ◽  
Amino Groups ◽  
Multiwalled Carbon ◽  
Epoxy Network ◽  
Epoxy Nanocomposite ◽  
Thermal Stability Of

The epoxy nanocomposites filled with 0.1, 0.5, and 1 wt% nanodiamonds (nanoD) were prepared and their properties were compared with neat epoxy network or epoxy nanocomposite filled with 1 wt% multiwalled carbon nanotubes (MWCNTs). The obtained nanoD-epoxy composites increased significantly thermal stability of prepared nanocomposites in comparison with neat epoxy matrix. The exponential decay of light transmittance with increasing concentration of nanoD in sample was observed. The values of storage modulus G` and glass transition temperature Tg significantly decreased by addition of nanoD to epoxy network. This is caused by inhibition of cross-linking reaction of epoxy- and amino- groups by nanoD.

scholarly journals Thermal decomposition kinetic study of multiwalled carbon nanotube buckypaper-reinforced poly(ether-imide) composites

2017 ◽  
Vol 32 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Bruno Ribeiro ◽  
LFP Santos ◽  
AL Santos ◽  
ML Costa ◽  
EC Botelho
Keyword(s):  
Thermal Stability ◽  
Carbon Nanotube ◽  
Life Time ◽  
Strong Increase ◽  
Multiwalled Carbon ◽  
Vacuum Filtration ◽  
Degradation Temperature ◽  
Triton X ◽  
Thermal Stability Of ◽  
Filtration Technique

Poly(ether-imide) (PEI)-based composites filled with multiwalled carbon nanotubes in a dispersed form (1.0 wt%) and as buckypaper (BP) (25 wt%) have been prepared by mixing solution and hot compression molding technique, respectively. Vacuum filtration technique with the aid of water-based surfactant Triton X-100 was employed to produce BP sheets. The thermal stability of the composites was evaluated by thermogravimetric analysis and revealed a strong increase in thermal degradation temperature when BPs were used as nanofiller. Ozawa–Wall–Flyn model was used to determine the kinetic parameters. It was observed an increase in activation energy as the nanotubes concentration rise, suggesting the formation of more thermally stable systems. In addition, half-life time as function of temperature demonstrated that BP-based composites could operate for 3200 years at 200°C. These results concluded that carbon nanotube BP could contribute to improve significantly the thermal stability of PEI matrix.

scholarly journals Effect of Multiwalled Carbon Nanotubes (MWNT) on the Properties of High Impact Polystyrene (HIPS)

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Juan Li
Keyword(s):  
Thermal Stability ◽  
Flame Retardancy ◽  
High Impact ◽  
Melt Blending ◽  
Flow Properties ◽  
Multiwalled Carbon ◽  
Elongation At Break ◽  
Morphological Behavior ◽  
The Impact ◽  
Thermal Stability Of

The composites of HIPS/MWNT were prepared by melt blending. The effects of the content of MWNT on the flow, mechanical, and flame retardancy properties of the composites were investigated. The morphologies of fracture surfaces were characterized through scanning electron microscopy (SEM). And the thermal stability of the composites was studied by thermogravimetric analysis. The results show that the flow properties, the impact strength, the elongation at break, and the flame retardancy are improved with the proper addition of MWNT. The morphological behavior indicates the fracture surface of HIPS/MWNT is more roughness than that of HIPS. The addition of MWNT has little influence on the thermal stability of HIPS.

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