Abstract
The compressive yield strength of glass microsphere – epoxy composites was evaluated as a function of the interface strength. The behaviour of composites with microspheres without any surface treatment was compared with that of composites fabricated with silane-treated and silicone oil-treated microspheres. Varying the hardener-to-epoxy ratio of the matrix also modified the interface. The results were compared with those derived from theoretical models, and it was shown that for hollow glass microsphere composites the effect of surface treatment can be quantitatively described using extant models. Changes in the reinforcing effect and stress concentration factor caused by the presence of the microspheres are discussed, and the experimental results explained.