Investigation and assessment of epoxy resin adhesives using Fourier‐transform infrared spectrometry

Abstract Epoxy resin adhesives are very attractive for many industries, especially in the aerospace and automotive industries because they eliminate heavy connection elements, such as bolts and screws, and reduce the total weight. This study assesses developed epoxy resin adhesives using Fourier‐transform infrared spectrometry. The curing reaction between Epikote 828 epoxy resin and Epikure polyamidoamine curing agent 3090, and the chemical structure of the additives (CAB‐O‐SIL TS‐720) used for rheology control and six different types of fillers (calcite with particle diameters of 700 nm, 5 μm, and 10 μm, coated calcite with a particle diameter of 900 nm, and barite and calcite with a particle diameter of 5 μm) employed in the adhesives are investigated. The Fourier‐transform infrared spectrometry results of the epoxy resin and curing agent demonstrate that 83.5 % epoxy conversion is achieved at a temperature of 25 °C. The chemical composition of the additives with six different types of fillers and 1 %, 3 %, and 5 % additions of CAB‐O‐SIL TS‐720 prepared in both nujol mull and potassium bromide discs is characterized using Fourier‐transform infrared spectrometry. The potassium bromide discs yield higher intensities owing to good packing of cubic particles of potassium bromide with nano particle size CAB‐O‐SIL TS‐720 and all filler types.