scholarly journals Structure, thermophysical properties and electrical conductivity of nanocomposites based on epoxy polymer and carbon tubes

2021 ◽  
pp. 7-13
Author(s):  
V.V. Korskanov ◽  
O.M. Fesenko ◽  
V.B. Dolgoshey
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Percolation Threshold ◽  
Thermophysical Properties ◽  
Epoxy Polymer ◽  
Transition Range ◽  
Epoxy Polymers

The aim of this work was to find the optimal conditions for the formation of nanocomposites, study their structure and properties and conditions for the formation of multicomponent materials based on epoxy polymers and carbon nanotubes with predetermined performance properties. The basis for the formation of epoxy polymers was an epoxydian oligomer (EDO) based on bisphenol A. Polypox H354 was used as a hardener for EDO. Carbon nanotubes (CNT) were used as a nanofiller for the preparation of nanocomposites. The research methods were a diffractometer for measuring the intensity of X-ray scattering in the region of small angles and a differential scanning calorimeter for obtaining heating thermograms. The electrical conductivity of the samples at a temperature of 293 K was measured at direct current according to the two-electrode scheme. In this work the structure, thermophysical properties and electrical conductivity of nanocomposites based epoxy polymers and carbon  nanotubes have been studied. It was found that at low CNT content the formation of nanocomposites occurs by the mechanism of epoxy network growth, which is accompanied by the displacement of CNT particles to the periphery of the epoxy matrix. This process is accompanied by an increase in the scattering intensity of the SAXS, a rapid increase in the glass transition temperature and the degree of crosslinking of the epoxy polymer. When the critical concentration is reached, CNT particles form a continuous cluster, which leads to occurrence percolation threshold, reducing the glass transition temperature, expanding the glass transition range, occurrence of pores and reducing the degree of completion of the crosslinking reaction in nanocomposites relative to the epoxy polymer. It is established that the improvement of nanocomposite properties and the occurrence of the percolation threshold is due to the maximum specific energy of ER-CNT interaction and is achieved at a critical mass concentration of nanofiller from 0,1% to 0,4%.

Characterization of Thermo-Electric Interface Material with Carbon Nanotubes

2007 ◽  
Vol 1056 ◽  
Author(s):  
Piyush R Thakre ◽  
Yordanos Bisrat ◽  
Dimitris C Lagoudas
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Matrix ◽  
Loss Modulus ◽  
Single Wall Carbon Nanotubes ◽  
Electrical Percolation

ABSTRACTAn approach has been presented in the current work to fabricate and characterize nanocomposite systems for optimizing electrical and thermal properties without sacrificing mechanical properties. An epoxy matrix based nanocomposite system has been processed with different volume fractions of carbon nanotubes. The purpose was to tailor macroscale properties to meet competing performance requirements in microelectronics industy. The nanofiller consisted of comparatively low cost XD grade carbon nanotubes (XD-CNTs) that are optimized for electrical properties. This system was compared with another system consisting of single wall carbon nanotubes (SW-CNTs) as nano-reinforcements in epoxy matrix. The electrical percolation threshold (about seven orders of magnitude increase in electrical conductivity) measured by dielectric spectroscopy was found to be at lower loading weight fraction of SWCNTs (0.015 weight %) as compared to XD-CNTs (0.0225 weight %). However, the electrical conductivity after percolation was higher for XD-CNTs reinforced epoxy with respect to SW-CNTs filled nanocomposites. The governing mechanisms for this phenomenon were investigated using transmission optical microscope. The enhancement in thermal conductivity, measured using differential scanning calorimetry, was found to be moderate at lower weight loadings corresponding to electrical percolation. However, a 90% improvement in thermal conductivity was observed for 0.3 weight percent of XD-CNTs. Dynamic mechanical analysis was performed to measure the storage and loss modulus along with the glass transition temperature. No significant change in modulus values and glass transition temperature was measured for nanocomposites varied filler contents with respect to neat matrix.

Dynamic Mechanical Analysis of Nanosilica Filled Epoxy Nanocomposites

2014 ◽  
Vol 699 ◽  
pp. 239-244 ◽  
Author(s):  
Nurhidayah R. Zamani ◽  
Aidah Jumahat ◽  
Rosnadiah Bahsan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Polymer ◽  
Loss Modulus ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Dynamic Mechanical ◽  
Mechanical Stirring ◽  
Tan Δ

In this study, Dynamic Mechanical Analyzer (DMA) was used to study the effect of nanoparticles, which is nanosilica, on glass transition temperature (Tg) of epoxy polymer. A series of epoxy based nanosilica composite with 5-25 wt% nanosilica content was prepared using mechanical stirring method. The weight fractions of nanosilica in epoxy were 5 wt%, 13 wt% and 25 wt%. 30mm x 10mm x 3mm size specimens were tested using DMA machine from room temperature up to 180oC at 2°C/min heating rate. From the analysis of the results, dynamic modulus and glass transition temperature of pure polymer and nanosilica filled polymer were obtained. The glass transition of a polymer composite is a temperature-induced change in the matrix material from the glassy to the rubbery state during heating or cooling. Glass transition temperature Tg was determined using several method: storage modulus onset, loss modulus peak, and tan δ peak. The results showed that the presence of nanosilica reduced Tg of epoxy polymer.

scholarly journals Morphology and Properties of Aminosilane Grafted MWCNT/Polyimide Nanocomposites

2008 ◽  
Vol 2008 ◽  
pp. 1-15 ◽  
Author(s):  
Siu-Ming Yuen ◽  
Chen-Chi M. Ma ◽  
Chin-Lung Chiang ◽  
Chih-Chun Teng
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Percolation Threshold ◽  
Multiwalled Carbon ◽  
Mwcnt Content ◽  
Glass Transition Temperatures ◽  
Novel Method ◽  
Polyimide Composites

This investigation presents a novel method for modifying multiwalled carbon nanotubes (MWCNTs). The morphology, electrical resistivity, and percolation threshold of MWCNT/Polyimide nanocomposites were studied. Acid-modified MWCNTs reacted with (3-aminopropyl)triethoxysilane by ionic bonding, and were then mixed with polyamic acid via imidization. TEM microphotographs reveal that silane-grafted MWCNTs were connected to each other. The electrical resistivity of silane-grafted MWCNT/polyimide decreased substantially below than that of acid-treated MWCNTs when the silane-modified MWCNT content was lower than 2.4 wt%. The percolation threshold of the MWCNT/polyimide composites is 1.0 wt% for silane-modified MWCNT and exceeds 7.0 wt% for acid-modified MWCNT. The acid-modified MWCNT/polyimide composites possess slightly higher glass transition temperatures than that of pure polyimide. The glass transition temperature of the polyimide increased significantly with silane-modified MWCNT content. Tensile properties of the polyimide have been improved with the MWCNTs content.

Effects of Electron Beam on Irradiated Polyimide/Polyaniline Composites

2012 ◽  
Vol 550-553 ◽  
pp. 861-864 ◽  
Author(s):  
Sunan Tiptipakorn ◽  
Piriyathorn Suwanmala ◽  
Kasinee Hemvichian ◽  
Yingpit Pornputtanakul
Keyword(s):  
Electrical Conductivity ◽  
Electron Beam ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Radiation Dose ◽  
Radiation Doses ◽  
Pani Composite ◽  
Polyaniline Composites

In this study, the composites prepared from polyimide (PI) and polyaniline (PANI) were radiated with electron beam (EB) at the radiation doses of 0, 50, 150, 200, and 300 kGy. The electrical conductivity and thermal properties of the radiated composites were determined and compared with those of the composites doped with 6M HCl. The results revealed that the electrical conductivity was enhanced from 3.42 x 10-16 S/cm (untreated polyimide without polyaniline) to 6.97 x 10-5 S/cm when the PI/PANI composite was doped with HCl at 10 phr of PANI; furthermore, the conductivity was increased to 2.16 x 10-4 S/cm for the composite at 10 phr of PANI with radiation dose of 200 kGy. In addition, it was found that the glass transition temperature of the composite was increased with the increase of PANI content for either EB radiation method or protonic acid doping method. It could be noted that the electrical conductivity values of the radiated composites were higher than those of composites doped with HCl at the same PANI content.

The Research of the Effect of Single-Walled Carbon Nanotubes on the Properties of Epichlorohydrin Rubber

2019 ◽  
Vol 945 ◽  
pp. 428-432
Author(s):  
E.N. Timofeeva ◽  
Natalia N. Petrova ◽  
K.N. Nikolaeva ◽  
E.S. Kuzmina
Keyword(s):  
Carbon Nanotubes ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Low Temperatures ◽  
High Performance ◽  
Single Walled Carbon Nanotubes ◽  
Elastomeric Materials ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The development of frost-resistant elastomeric materials with high performance characteristics remains one of the topical issues. Solving this issue will significantly improve the reliability of machines and mechanisms operating under extremely low temperatures. The influence of multi-walled carbon nanotubes on the performance properties of epichlorohydrin rubber was investigated. This rubber of unique frost resistance has low glass transition temperature (Tg = -60 °C).

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