Volume 8 Issue 2 ( June 2021 )


Formation of Porous Epoxy Micro-beads from a Single Droplet of Epoxy-Polyamide-Ammonium Bicarbonate at Different Temperatures

Anusha Leemsuthep, Zunaida Zakaria, Varaporn Tanrattanakul, Du Ngoc Uy Lan


Process temperature greatly affects the decomposition behavior of a blowing agent, and changes the structure of the porous epoxy. This paper investigates the effect of processing temperature on the decomposition rate and volume of decomposing gases from ammonium bicarbonate as well as the properties of porous epoxy micro- bead through a single epoxy droplet. A single epoxy droplet (epoxy-polyamide-ammonium bicarbonate) was dropped into the corn oil heated at the temperatures of 80°C, 90°C and 100°C. This study found that by controlling the processing temperature, an epoxy foam bulk (80°C) or a number of porous epoxy micro-beads were fabricated (90°C and 100°C). Higher total volume of gas was generated which was 1142.86 cm3/g at 100°C, with lower viscosity of epoxy. Therefore, the initial epoxy droplet of 10:6 ratio burst into smaller micro- beads with dominant sizes in the range of 251-500 μm and porosity of 30%. From the perspective of epoxy polyamide ratios, the 10:10 ratio has porous epoxy micro-beads slightly larger than that of 10:6 ratio. This induced a decrease in porosity and an increase in specific gravity of micro-beads of 10:10 ratio.

Keywords: blowing agent, decomposition rate, emulsion, particle size, stoichiometric