Evaluation of carbon-based nanostructures suitable for the development of black pigments and glazes

Preparation of black lyophilic ink using the carbon soot emitted by vehicles

The carbon soot is formed as a consequence of incomplete combustion of hydrocarbons and organic matter. It causes respiratory diseases like lung cancer and asthma and contributes to 1.6 million premature deaths every year. The primary source of soot is the vehicular emissions which can be controlled using a simple device retrofitted to the silencer. In the present study, various additives were added to the collected soot, forming a homogenous adhering suspension which can be used as an ink. Tests proved that this ink is safe to use and it also complied with the standards of the Indian Government for fountain pen ink. The ink had excellent water-resistant properties as a result of its R_f (retention factor) value was found to be 0.0133. When compared with conventional black inks, the ink dries quickly, and on varying the temperature of the surroundings from - 30 to 50 °C, the ink remained in the writable viscosity range of 4.6 to 4.9 mPa s, thus making it universally malleable. The ink also proved to be UV resistant and neither exhibited feathering, show-through, bleeding nor shading. The ink is versatile; it can be used for a wide range of applications including writing, painting, and spraying.

Experimental Investigation of the Melt Shear Viscosity, Specific Volume and Thermal Conductivity of Low-Density Polyethylene/Multi-Walled Carbon Nanotube Composites Using Capillary Flow

Understanding the flow behavior of polymer/carbon nanotube composites prior to melt processing is important for optimizing the processing conditions and final product properties. In this study, the melt shear viscosity, specific volume and thermal conductivity of low-density polyethylene (LDPE) filled with multi-walled carbon nanotubes (MWCNTs) were investigated for representative processing conditions using capillary rheometry. The experimental results show a significant increase in the melt shear viscosity of the LDPE/MWCNT composite with nanotube loadings higher than 1 wt.%. Upon increasing shear rates, the composites flow like a power-law fluid, with a shear-thinning index less than 0.4. The specific volume decreases with increasing pressure and nanotube loading, while the pVT transition temperature increases linearly with increasing pressure. The thermal conductivity of the LDPE/MWCNT composite is nearly independent of nanotube loading up to the thermal percolation threshold of 1 wt.% and increases linearly with further increases in nanotube loading, reaching 0.35 W/m·K at 5 wt.%. The Carreau-Winter and Cross viscosity models and Tait equation, respectively, are able to predict the shear viscosity and specific volume with a high level of accuracy. These results can be used not only to optimize processing conditions through simulation but also to establish structure-property relationships for the LDPE/MWCNT composites.