scholarly journals Synthesis and Physicochemical Characterization of Multiwalled Carbon Nanotubes/Hydroxamic Alginate Nanocomposite Scaffolds

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Aline Margarete Furuyama Lima ◽  
Marcelo de Freitas Lima ◽  
Odílio Benedito Garrido Assis ◽  
Alice Raabe ◽  
Hemelen Caroline Amoroso ◽  
...  

In this study, the preparation of porous nanocomposite scaffolds (HX-CNT) from a combination of a hydroxamic derivative of alginate (HX) and an amine-functionalized multiwalled carbon nanotube (CNT) at different concentrations is described. The structure of HX was investigated by FTIR, and the degree of substitution around 9% was confirmed by elemental analysis. The interaction between CNT and alginate derivative in the nanocomposite crosslinked with calcium was confirmed by FTIR, Raman spectroscopy, and SEM. The results obtained in this study showed that scaffolds based on HX-CNT composites with a 4 wt% concentration level exhibited improved physical and mechanical properties compared to plain alginate (Young’s modulus increased from 2.2 to 5.1 MPa and elastic strength from 0.13 to 0.25 MPa) and decreased the swelling ratios from ~900 to ~673. The cytotoxicity assays using the L929 cell line proved that the nanocomposite scaffolds were nontoxic, even at the highest CNT concentration.

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1284
Author(s):  
Asar Ali ◽  
Farman Ali ◽  
Ahmad Rashedi ◽  
Ammar Armghan ◽  
M. R. Nurul Fajita ◽  
...  

In this work, piezoresistive properties of graphene-multiwalled carbon nanotubes (MWCNTs) composites are investigated, characterized, and compared. Sandwich-type composite piezoresistive pressure-sensitive sensors (Ag/Graphene-MWCNT/Ag) with the same diameters, but different fabrication pressures and thicknesses were fabricated using the mortar and pestle/hydraulic press technique. To produce low-electrical-resistance contacts, both sides of the composite sensors were painted with silver (Ag) paste. All the sensors showed reductions in the direct current (DC) resistance ‘R’ with an increment in external uniaxial applied pressure. However, it was observed that higher fabrication pressure led to a lower resistance value of the composite, while the thicker samples give lower electrical conductivity and higher resistance than the thinner samples. The experimental data for all composite pressure sensors were in excellent agreement with the simulated results.


Author(s):  
K. J. Morrissey

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.


Author(s):  
Thais Helena Sydenstricker Flores-Sahagun ◽  
Kelly Priscila Agapito ◽  
ROSA MARIA JIMENEZ AMEZCUA ◽  
Felipe Jedyn

2019 ◽  
Vol 38 (2) ◽  
pp. 385 ◽  
Author(s):  
Marwa M. El-Naggar ◽  
Wael S. I. Abou-Elmagd ◽  
Ashraf Suloma ◽  
Hamza A. El-Shabaka ◽  
Magdy T. Khalil ◽  
...  

Author(s):  
Kumar P ◽  
S Kumar ◽  
A Kumar ◽  
M Chander

The purpose of this study was to prepare and characterize solid dispersions of the antibacterial agent Cefdinir with PEG 4000 and PVP K-30 with a view to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Cefdinir was considerably improved when formulated in solid dispersions with PVP K-30 and PEG 4000 as compared with pure drug and physical mixtures. The results from XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction.


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