scholarly journals Influence of Silanization Treatment on Thermomechanical Properties of Multiwalled Carbon Nanotubes: Poly(methylmethacrylate) Nanocomposites

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Carlos Velasco-Santos ◽  
Ana Laura Martinez-Hernandez ◽  
Witold Brostow ◽  
Victor M. Castaño

Unfunctionalized and silanized multiwalled carbon nanotubes (MWNTs) were incorporated in poly(methylmethacrylate) matrices usingin situpolymerization. Polymer-compatible functional groups on carbon nanotube (CNT) surfaces were characterized by infrared spectroscopy. These chemical moieties improve interaction at interfaces, allowing transfer of mechanical load between the matrix and the dispersed phase as reflected in the resulting improved mechanical and thermophysical properties. The composites were characterized by Raman spectroscopy to evaluate molecular level interactions and dynamical mechanical analysis. Composites with silanized CNTs have higher storage modulus (E′) than polymer reinforced with unfunctionalized nanotubes. Considering the average of the samples, only 1 wt.% of silanized nanotubes provides an increase inE′ of 165% at room temperature with respect to polymer matrix, and the increments reached are by a factor of 6.8 and 13.6 over the polymer matrix at 80°C and 90°C, respectively. 1 wt% of silanized CNTs increases the glass transition temperature of polymer matrix around 30°C. Microscratch testing results of composites show that unfunctionalized CNTs cause deeper penetration of the indenter than polymer matrix at the same force; however, the composites developed with silanized CNTs present more regular behavior than polymer reinforced with unfunctionalized CNTs.

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 763 ◽  
Author(s):  
Xiaogang Luo ◽  
Zengcheng Yu ◽  
Yixin Cai ◽  
Qiangxian Wu ◽  
Jian Zeng

It is challenging to prepare polyurethane bioplastics from renewable resources in a sustainable world. In this work, polyurethane nanocomposite bioplastics are fabricated by blending up to 80 wt % of soy-based polyol and petrochemical polyol with hydroxyl-functionalized multiwalled carbon nanotubes (MWCNTs-OH). The scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR) analyses reveal homogeneous dispersion of the MWCNTs-OH in the matrix, as well as interaction or reaction of MWCNTs-OH with the matrix or polymeric methylene diphenyl diisocyanate (pMDI) in forming the organic–inorganic hybrid bioplastic with a three-dimensional (3D) macromolecule network structure. Mechanical properties and electrical conductivity are remarkably enhanced with the increase of the multiwalled carbon nanotube (MWCNTs) loading. Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) results show that the bioplastics with MWCNTs-OH have a better thermal stability compared with the bioplastics without MWCNTs-OH. The composition of the nanocomposites, which defines the characteristics of the material and its thermal and electrical conductivity properties, can be precisely controlled by simply varying the concentration of MWCNTs-OH in the polyol mixture solution.


2014 ◽  
Vol 809-810 ◽  
pp. 43-52
Author(s):  
Hua Hua Wang ◽  
Nan Li ◽  
Kai Li ◽  
Yuan Bu ◽  
Wen Le Dai ◽  
...  

Multiwalled carbon nanotubes (MWCNTs) as an excellent supporter covered with a thick layer of cobalt phthalocyanine (CoPc) were prepared by in-situ synthesis. Platinum particles were adopted to enhance the conductivity of CoPc-MWCNTs. The final nanocomposite Pt-CoPc-MWCNTs was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Strong aromatic π-π stacking between MWCNTs and CoPc made CoPc in-situ forming on MWCNTs. With homogeneous thickness of CoPc covered on the MWCNTs and Pt particles equally distributed, the nanocomposite was used as electrocatalyst. The electrochemical properties of the composite got researched by casting the dispersion of Pt-CoPc-MWCNTs on the glassy carbon electrode. Compared with other modified electrodes, Pt-CoPc-MWCNTs/GC electrode exhibited excellent electrochemical activity towards dopamine (DA) and uric acid (UA). Linear responses for DA and UA were obtained in the ranges of 5 to 170 μM and 5 to 100 μM, and limits of detection were 2.6 and 1.4 μM (S/N= 3), respectively. Simultaneous detection of DA and UA in the presence of ascorbic acid (AA) also displayed selective property, with no interference to each other.


2019 ◽  
Vol 53 (24) ◽  
pp. 3413-3431 ◽  
Author(s):  
Kadir Bilisik ◽  
Nesrin Karaduman ◽  
Gulhan Erdogan ◽  
Erdal Sapanci ◽  
Sila Gungor

The in-plane shear properties of nanostitched three-dimensional (3D) carbon/epoxy composites were investigated. Adding the stitching fiber or multiwalled carbon nanotubes or nanostitched fiber into carbon fabric preform slightly improved the shear strength and modulus of stitched and stitched nanocomposites. The in-plane shear fracture of the base and nanostructures was extensive delamination and tensile fiber failures in the sheared region. But, the stitched and stitched nanocomposites had angular deformation of the stitching yarns in the fiber scissoring areas, shear hackles in the matrix and successive fiber breakages in the interlayers. Probably, this mechanism prohibited extensive interlayer opening in the nanostitched composites. The results exhibited that introducing the stitching fiber (1.44%) and multiwalled carbon nanotubes (0.03125%) in the base structure enhanced its transverse fracture properties as a form of confined delamination area. Therefore, the damaged tolerance properties of the stitched nanocomposites were enhanced.


2017 ◽  
Vol 8 ◽  
pp. 1328-1337 ◽  
Author(s):  
Bertha T Pérez-Martínez ◽  
Lorena Farías-Cepeda ◽  
Víctor M Ovando-Medina ◽  
José M Asua ◽  
Lucero Rosales-Marines ◽  
...  

Film forming, stable hybrid latexes made of methyl metacrylate (MMA), butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA) copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs) were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (T g and insoluble polymer fraction). The performance of the in situ composites was compared with that of the neat polymer dispersion as well as with those of the polymer/MWCNT physical blends. The in situ composites showed the presence of an additional phase likely due to the strong interaction between the polymer and MWNCTs (including grafting) that reduced the mobility of the polymer chains. As a result, a substantial increase of both the storage and the loss moduli was achieved. At 60 °C, which is above the main transition region of the polymer, the in situ composites maintained the reinforcement, whereas the blends behaved as a liquid-like material. This suggests the formation of a 3D network, in good agreement with the high content of insoluble polymer in the in situ composites.


Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1596 ◽  
Author(s):  
Artemiy Aborkin ◽  
Kirill Khorkov ◽  
Evgeny Prusov ◽  
Anatoly Ob’edkov ◽  
Kirill Kremlev ◽  
...  

Aluminum matrix composites reinforced with multiwalled carbon nanotubes (MWCNTs) are promising materials for applications in various high-tech industries. Control over the processes of interfacial interaction in Al/MWCNT composites is important to achieve a high level of mechanical properties. The present study describes the effects of coating MWCNTs with titanium carbide nanoparticles on the formation of mechanical properties and the evolution of the reinforcement structure in bulk aluminum matrix nanocomposites with low concentrations of MWCNTs under conditions of solid-phase consolidation of ball-milled powder mixtures. Using high-energy ball milling and uniaxial hot pressing, two types of bulk nanocomposites based on aluminum alloy AA5049 that were reinforced with microadditions of MWCNTs and MWCNTs coated with TiC nanoparticles were successfully produced. The microstructural and mechanical properties of the Al/MWCNT composites were investigated. The results showed that, on the one hand, the TiC nanoparticles on the surface of the MWCNT hybrid reinforcement reduced the damage of reinforcement under the intense exposure of milling bodies, and on the other hand, they reduced the contact area of the MWCNTs with the matrix material (acting as a barrier interface), which also locally inhibited the reaction between the matrix and the MWCNTs.


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