| Abstract: | Nomex/Thermoset honeycombs with hexagonal cell shape were fabricated by impregnating the Nomex T412 paper using a resol, a resol modified with 20 phr of a bismaleimide and a resol modified with 20 phr of a poly(vinyl butyral) (PVB) respectively. The density of the honeycombs ranged from 2.0 to 4.0 lb/ft3. To fabricate the Nomex/Thermoset honeycombs with dimensions of 300×300×50 mm, an expansion procedure was employed. An epoxy-based adhesive system comprising 4,4′-tetraglycidyl diaminodiphenyl methane 35%, diaminodiphenyl sulfone 12%, the resol 35% and the PVB 18% was formulated and used to bond honeycomb cell nodes before expanding stacked ribbons. The adhesive blend was formulated to obtain a good honeycomb shape by reducing spreading of the resin during cure. The cure behaviors of the adhesive and the resol were investigated by differential scanning calorimetry. The compressive mechanical properties of the honeycombs were investigated and the effects of the impregnating thermoset resin systems on the compressive mechanical properties of the honeycombs were analyzed. The effect of the compressive mechanical properties of the honeycombs comprising pure resol on cure conditions was investigated. © 1997 John Wiley & Sons, Ltd. |
