Modification of epoxy resin by polysulfone to improve the interfacial and mechanical properties in glass fibre composites. I. Study of processes during matrix/glass fibre interface formation

The rheology of epoxy resin-polysulfone blends and wetting at the blend/glass fibre interface have been studied. Measurements were made in a rotary viscometer and in a modified Wilhelmy apparatus. It was shown that none of the blends investigated revealed non-Newtonian behaviour in the range of shear rates used. The viscosity of the blends increased as polysulfone content increased. Introduction of hardener resulted in a significant increase of the blends viscosity up to 2-3 orders of magnitude. Rheological tests suggested that 15 wt% polysulfone was the highest concentration useful for obtaining composites by solvent-free impregnation technique. These tests suggested that the structure of the cured epoxy-polysulfone blends depended on the modifier concentration. The structures of the blends differed for the blends containing 5 wt% polysulfone and 10-15 wt% polysulfone. All the blends (with the hardener) required at least 30 min at 180°C to achieve final values of the mechanical properties such as storage...