Sadia Sagar

Fabrication and thermal characteristics of functionalized carbon nanotubes impregnated polydimethylsiloxane nanocomposites

Multiwalled carbon nanotubes (MWCNTs) were modified to covalently attach the carboxylic moiety with their surfaces. Variant concentrations of functionalized multiwalled carbon nanotubes (F-MWCNTs) were introduced into polydimethylsiloxane (PDMS) adopting solution mixing technique. Fourier transform infrared spectroscopy (FTIR) confirms the carboxy functionalization presence on the surface of the nanotubes. X-ray diffraction (XRD) patterns for both MWCNTs and F-MWCNTs illustrate that the crystallinity does not alter with surface modification of the nanotubes. Experimental results simulated that electrical conductivity of the nanocomposites was augmented with increasing filler concentration in the host matrix. Thermal conductivity and thermal impedance of the nanocomposite specimens were evaluated according to developed methodologies and the accumulative data revealed the nanocomposites thermal transport dependence on the F-MWCNTs doping concentration in the host polymer matrix. Thermal stability enhancement with increasing filler incorporation into the polymer matrix was observed in thermogravimetric/differential thermal analyzer (TG/DTA) contours. Crystallization, glass transition, and melting temperatures were examined using differential scanning calorimeter (DSC) and it was observed that phase transition temperatures of the composite specimens can be tuned by varying the nanotubes to matrix ratio. Scanning electron microscopy and energy dispersive x-ray spectroscopy were carried out to analyze the surface morphology/composition of the fabricated nanocomposites and dispersion of functionalized and pristine MWCNTs in the polymer matrix.

MWCNTS Incorporated Natural Rubber Composites: Thermal Insulation, Phase Transition and Mechanical Properties

The effect of variant concentrations of multiwalled carbon nanotubes (MWCNTs) on the thermal transport, phase transition temperatures, and mechanical properties of polyisoprene rubber have been studied in the present novel research. MWCNTs were incorporated into the natural rubber (NR) using shear mixing techniques. Microscopy results reveal the uniform dispersion of the nanotubes within the polymer matrix. Thermal conductivity and thermal insulation of the fabricated composites were evaluated according to ASTM standards. Thermal transport through the nanocomposite specimens is restricted by the nanotubes network developed within the polymer matrix. Differential scanning calorimetric study elucidates the reduction of crystallization (T c ) and glass transition (T g ) temperatures, while melting temperature (T m ) enhances with increasing the nanotubes concentration in the rubber matrix. A remarkable enhancement in mechanical properties of MWCNT/NR composites was observed with increasing nanotube to matrix ratio. techniques to fabricate nanocomposites for engineering applications, i.e., automobile industry, sports industry, membrane technology, aerospace industry, energy storage and many more. In order to fabricate an affective composite, aspect ratio of the nanotube should not be diminished. The CNTs/polymer nanocomposites have also shown outstanding thermal stability in nitrogen as well as in oxygen atmospheres. Uniformly dispersed nanotubes develop a network in a polymer matrix that restricts the thermal mobility of polymeric chains in the heat atmosphere (3). Polyisoprene rubber (NR) with superb thermal/mechanical properties, oil/hot air ageing and swelling resistance has extensively used in automobile and oil industries. Selection and designing of a composite for a specific application necessitate its thermal transport/endurance data. Evaluation of thermal properties for a polymer nanocomposite has great importance to allocate relevance area of application. This paper reports the novel investigation of thermal impedance, thermal conductivity, thermal composition, heat flow response, glass transition/crystallization/melting temperatures, and specific enthalpies of NR nanocomposites with five diverse loadings of pristine multiwalled carbon nanotubes (MWCNTs).

Ablation, thermal stability/transport and mechanical investigations of modified nanokaolinite impregnated acrylonitrile butadiene rubber composites

Modified nanokaolinite was uniformly dispersed in acrylonitrile butadiene rubber using dispersion kneader and two roller mixing mill. In order to evaluate ablation characteristics of the fabricated composites, high-temperature ablation testing was carried out. The peak incorporation of nanoclay in the rubber matrix has enhanced the ablation resistance up to 97% and reduced the temperature elevation at the back face of the nanocomposite up to 51% during the 200s oxy–acetylene flame exposure on the surface of the ablator. Thermogravimetric and differential thermal analyses elucidate the thermal endurance improvement with increasing filler contents in the polymer matrix. Thermal conductivity and thermal impedance of the composite specimens were evaluated on the domestically manufactured thermal conductivity measuring apparatus. It is scrutinized that the former property reduced up to 49% at and the subsequent characteristic of the rubber composite is elevated up to 43% at 373 K with the 30 wt% incorporation of the nanoclay into the base rubber composition. Mechanical properties of the acrylonitrile butadiene rubber composite specimens were significantly enhanced with increasing filler introduction into the host matrix. Porous char morphology, polymer pyrolysis and composition of the ablated samples were analyzed using scanning electron microscopy and energy dispersive spectroscopy analyses.

Multiwalled carbon nanotubes impregnated rubber nanocomposites: thermal transport/decomposition and differential scanning calorimetric study

In order to analyze the effect of multiwalled carbon nanotubes on the thermal transport/stability characteristics of styrene butadiene rubber, five diverse loadings of multiwalled carbon nanotubes were impregnated in the rubber matrix using dispersion kneader and two roller mixing mill. Thermal conductivity and thermal impedance of the nanocomposite specimens were evaluated according to ASTM E1225-99 and D5470-03. It was observed that the thermal conductivity was reduced up to 79% while thermal impedance of the polymer nanocomposite was improved up to 390% at 523 K with 1 wt% impregnation of nanotubes into the base composite formulation. Thermal stability of the polymer nanocomposite was augmented up to 6%, with the utmost incorporation of the nanotubes. Glass transition and crystallization temperatures were diminished, while the onset and peak melting temperatures were increased with increasing filler to matrix ratio. The percent crystallinity of the nanocomposites has been augmented up to 5%, with 1 wt% incorporation of multiwalled carbon nanotubes into the host matrix. Scanning electron microscopy along with energy dispersive X-ray spectroscopy was used to examine the multiwalled carbon nanotubes dispersion in the rubber matrix, for surface analysis of the post-thermally tested composite specimens and for their compositional analysis.