Effects of viscous flow activation energies and viscosities on waterborne light-diffusion dip-coatings

Abstract

Purpose

This paper aims to prepare good waterborne light-diffusion dip-coatings (WLDDC) for the glass lampshade inner walls of LED lamp tubes, the effects of viscosities and viscous flow activation energies on these dip-coatings were investigated.

Design/methodology/approach

The WLDDC were prepared using white pigments, light-diffusion agents, additives and an acrylic emulsion. The dip-coatings were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and a digital rotational viscometer, respectively. The effects of shear rates, temperatures and solids contents on the viscosities of the dip-coatings were studied. The viscous flow activation energies of these dip-coatings and the emulsion were calculated, compared and studied, respectively.

Findings

The results showed that the non-Newtonian behaviors of these dip-coatings were more prominent than that of the acrylic emulsion. When the temperature was maintained to be a constant and the shear rate was increased, the viscosity decreased and the shear stress increased. When the shear rate was maintained to be a constant, the viscosity decreased with increasing temperatures. The viscous flow activation energies of these dip-coatings decreased with the increasing shear rates. The higher solid contents of WLDDC were, the more its viscosity would decrease with the increasing shear rates, the more prominent its non-Newtonian behaviors would show.

Practical implications

A sample of good WLDDC with balanced properties was illustrated.

Originality/value

This investigation benefits to investigate waterborne environment-friendly dip-coatings for the inner glass walls of lamp tubes. This research provides an approach to optimize the viscosity parameters of light-diffusion dip-coatings.

Citation

Fang, T. and Ye, D. (2019), "Effects of viscous flow activation energies and viscosities on waterborne light-diffusion dip-coatings", Pigment & Resin Technology, Vol. 48 No. 5, pp. 415-420. https://doi.org/10.1108/PRT-07-2018-0066