Processing of interpenetrating composites

Interpenetrating composites are emerging as a new class of materials due to their potential for displaying multifunctional properties. They consist of three-dimensionally interpenetrating matrices of two different phases. In the present work the primary focus has been on ceramic/polymer composites though some work has also been done on ceramic/metal systems. The ceramic/polymer composites have been produced by infiltrating alumina foams with polyester resin. The foams are made by mechanically agitating ceramic suspensions to entrain gases and then setting the structure via the in-situ polymerisation of the organic monomers. This resulted in the foams having a very open and interconnected structure that could be easily infiltrated using simple, low pressure systems. Both positive and negative pressures have been investigated, the former yielded higher final densities since the later encouraged the entrapment of gas within the liquid polymer that remained in the composite. [Continues.]