A review of current knowledge and future trends in polymer/boehmite nanocomposites

Boehmite [bey-mahyt] is a unique aluminum oxide hydroxide nanostructure. It consists of nanosheets of octahedral aluminum ions with surface hydroxyl groups. Owing to exceptional reinforcing behavior, boehmite nanoparticles have gained immense attention as polymeric nanofillers. Essential matrices used with the boehmite based nanocomposites include poly(methyl methacrylate), polyethylene, polypropylene, polyamide, epoxy, and other polymers. In this review, all-inclusive considerations on the design, morphology, mechanical, thermal, electrical, ion conducting, flame retardancy, electrochemical, and other physical properties, and advances related to the polymer/boehmite nanocomposites are presented. The polymer/boehmite nanocomposites have been employed for the membranes (water filtration/dye removal), coatings (anti-corrosion/self-healing), Li-ion batteries, and non-flammability purposes.

Experimental and numerical investigations on a high-density polyethylene (HDPE) blown film cooling with a new design of the counter-flow/radial jet air-ring

This study experimentally and numerically investigates a typical HDPE blown film production process cooled via a single-lip air-ring. The processing observations are considered for the proposed subsequent modifications on the air-ring design and the location relative to the die to generate a radial jet, directly impinging on the bubble. Measurements are performed to collect the actual operating parameters to set up the numerical simulations. The radiation heat transfer and the polymer phase change are considered in the numerical simulations. The velocity profile at the air-ring upper-lip is measured via a five-hole Pitot tube to compare with the numerical results. The comparison between the measurements and the numerical results showed that the simulations with the STD [Formula: see text] turbulence model are more accurate with a minimum relative absolute error (RAE) of 1.6%. The numerical results indicate that the peak Heat Transfer Coefficient (HTC) at the impingement point for the modified design with radial jet and longer upper-lip is 29.1% higher than the original design at the same conditions. Besides, increasing the air-ring upper-lip height increased the averaged HTC, which is 13.4% higher than the original design.

Influence of magnetohydrodynamics and heat transfer on the reverse roll coating of a Jeffrey fluid: A theoretical study

The purpose of this article is to provide a mathematical model of magnetohydrodynamic (MHD) non-isothermal flow of an incompressible Jeffrey fluid as it goes through a minimal gap between the two counter rotating rolls. The dimensionless forms of governing equations are obtained by using appropriate dimensionless parameters. The LAT (lubrication approximation theory) is utilized to simplify the dimensionless form of governing equations. Analytical solutions for the velocity, pressure gradient, flow rate, Nusselt number and temperature distribution are presented. How the Jeffrey parameters, MHD and velocities ratio influence on the flow patterns and heat transfer rate are explored. Outcomes of some significant engineering quantities such as flow rate, power input, pressure distribution and roll separation force are obtained numerically in tabular form and some are displayed graphically. We found that the MHD parameter served as a controlling parameter for different engineering quantities like velocity, temperature, flow rate, and coating thickness. Moreover, the coating thickness on the web decreases by increasing the values of velocities ratio.

Advances in polystyrene/graphene nanoplatelet nanocomposites

This article analyses research trials on noteworthy features and technological impact of the polystyrene/graphene nanoplatelet nanocomposites. In polystyrene matrix, graphene nanoplatelets have been used as remarkable nanofiller. Substantial improvements in polystyrene physical properties occurs by adding low nanofiller content. Simple in situ, emulsion, solution, or melt synthesis strategies have been used to develop polystyrene/graphene nanoplatelet nanocomposite. The polystyrene/graphene nanoplatelet nanocomposites possess enhanced structural features, morphology, glass transition temperature, thermal stability, mechanical strength, electrical characteristics, sensing, capacitance, and other physical properties. The performance of the polystyrene/graphene nanoplatelet nanocomposites have been explored for the practical applications in the fields of sensing, electromagnetic interference shielding, and flame retardant materials.