Comparative evaluation of the effectiveness of PTFE nanoparticles on cement pastes properties with multi-wall carbon nanotubes, graphene oxide and silver nanoparticles

2022 ◽  
Vol 319 ◽  
pp. 126077
Author(s):  
Barış Şimşek ◽  
Tayfun Uygunoğlu ◽  
Ömer Faruk Dilmaç
Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4149
Author(s):  
Laura M. Echeverry-Cardona ◽  
Natalia Álzate ◽  
Elisabeth Restrepo-Parra ◽  
Rogelio Ospina ◽  
Jorge H. Quintero-Orozco

This study shows the energy optimization and stabilization in the time of solutions composed of H2O + TX-100 + Multi-Wall Carbon Nanotubes (MWCNTs), used to improve the mechanical properties of Portland cement pastes. For developing this research, sonication energies at 90, 190, 290, 340, 390, 440, 490 and 590 J/g are applied to a colloidal substance (MWCNTs/TX-100 + H2O) with a molarity of 10 mM. Raman spectroscopy analyses showed that, for energies greater than 440 J/g, there are ruptures and fragmentation of the MWCNTs; meanwhile at energies below 390 J/g, better dispersions are obtained. The stability of the dispersion over time was evaluated over 13 weeks using UV-vis spectroscopy and Zeta Potential. With the most relevant data collected, sonication energies of 190, 390 and 490 J/g, at 10 mM were selected at the first and the fourth week of storage to obtain Portland cement specimens. Finally, we found an improvement of the mechanical properties of the samples built with Portland cement and solutions stored for one and four weeks; it can be concluded that the MWCNTs improved the hydration period.


NANO ◽  
2008 ◽  
Vol 03 (01) ◽  
pp. 37-44 ◽  
Author(s):  
MOHSEN ADELI ◽  
ALI BAHARI ◽  
HODA HEKMATARA

Novel biodegradable nanocomposites containing multi wall carbon nanotubes (MWCNT) and poly(citric acid) (PCA) were successfully synthesized. For preparation of nanocomposites, MWCNT was opened using a mixture of sulfuric and nitric acid and its derivative containing – COOH and – OH functional groups was obtained. Polycondensation of monohydrate citric acid in the presence of functionalized MWCNT in the melting state was lead to nanotube-graft-poly(citric acid) (CNT-g-PCA) nanocomposites. The degree of polymerization of grafted hyperbranched poly(citric acid) onto the CNTs was controlled using CNT/citric acid ratio. The CNT-g-PCA were soluble in water freely and stirring their water solution and silver nitrate at room temperature lead to the CNT-g-PCA containing encapsulated silver nanoparticles in their polymeric shell. The structure of nanocomposites was characterized by TEM, DLS and spectroscopy methods.


2009 ◽  
Vol 08 (06) ◽  
pp. 533-541 ◽  
Author(s):  
MOHSEN ADELI ◽  
REZA SEPAHVAND ◽  
ALI BAHARI ◽  
BANDAR ASTINCHAP

Polycaprolactone-polylactide block copolymers (PCL-block-PLA) were grafted onto filled multi-wall carbon nanotubes (MWCNT) successfully. In this synthesis, MWCNTs were opened and functionalized, and then they were filled by silver nanoparticles. The filled MWCNT were used as macroinitiator for ring opening polymerization of ε-caprolactone and L-lactide. Then the end hydroxyl functional groups of MWCNT-graft-PCL or MWCNT-graft-PLA were used as initiator for ring opening polymerization of lactide and ε-caprolactone and MWCNT-graft-PCL-block-PLA or MWCNT-graft-PLA-block-PCL were obtained, respectively. Length of grafted copolymer chains onto the MWCNT was controlled using CNT/monomer ratio. Nanocomposites' properties depend on the length of polymer blocks strongly. Structure of nanocomposites was evaluated by TEM and spectroscopy methods.


2014 ◽  
Vol 880 ◽  
pp. 212-218 ◽  
Author(s):  
Alexander A. Gusev ◽  
Olga A. Akimova ◽  
Olga V. Zakharova ◽  
Anna Yu. Godymchuk ◽  
Yury A. Krutyakov ◽  
...  

Thepaper Presents Biological Properties of Threefine-Dispersed Materials, Namely Metallurgical Sludge, Colloidal Silver Andmulti-Wall Carbon Nanotubes (MWCNT) Exposing Oilseed Rape Plants. the Stimulationof Plant’s Growth by Silver Nanoparticles and the Intensification of Plantpigments Synthesis by MWCNT have been Experimentally Demonstrated. A Small Decreasein Energy and Germination Capacity were Noticed Whereby Colloidal Silver Hadthe Lowest Suppressive Effect, MWCN Tubes had the Highest Effect, and Sludge Wasfound in between Two above-Mentioned Materials. According to the Research, the Usageof Sludge is the most Effective at the Concentration of 10 and 100 g/l,colloidal Silver – 10 g/l and 300 g/l, MWCNT – 0,001 g/l and 1 g/l.


RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64739-64748 ◽  
Author(s):  
Taotao Yang ◽  
Yansha Gao ◽  
Jingkun Xu ◽  
Limin Lu ◽  
Yuanyuan Yao ◽  
...  

This study focuses on enhancing the catalytic activity of metallic Ni by using 1D MWCNTs, 2D GO and GR, and 3D GO–MWCNTs as supporting matrixs for the fabrication of electrochemical sensor for detecting the flavonoid luteolin.


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