Thermal conductivity of AlN/polystyrene interpenetrating networks

A new processing technique is proposed for preparing AlN/polystyrene interpenetrating network composites. This technique is based on an infiltration procedure, partly conducted in vacuo, of a liquid mixture of monomer and initiator into a porous A1N ceramic body with a percolated pore structure. Successive in situ polymerization is produced by heating up the infiltrated ceramic at ≈100°C under ambient pressure. The final morphology of the composite consists of an interpenetrating polymer network which fills in an A1N ceramic skeleton. This new infiltration procedure enabled us to prepare continuous polymeric networks whose volume fraction lies between ≈12 and 40 vol%. These fractions of polymer are consistently lower than that usually involved in traditional polymer moulding processes. It is shown both by experiments and theory that these special interpenetrating network microstructures experience relatively high thermal conductivity. Concurrently, significantly improved fracture characteristics and reliability can be achieved as compared with both that of monolithic ceramics and traditional polymeric materials containing high fractions of ceramic filler.