Thermal expansion behaviour of polystyrene-aluminum nitride composites

The thermal expansion behaviour of polymer composites having a matrix of polystyrene containing aluminum nitride (AlN) reinforcement has been investigated under a special dispersion state of filler in the composite: AlN filler particles surrounding polystyrene matrix particles. It is found that the coefficient of thermal expansion (CTE) of the composite is about 0.3 of that of polystyrene at about 20% volume fraction of AlN. The particle size of the polymer matrix is also found to have an effect on the thermal expansion of the polymer composite under this dispersion state. The dependence of the transition temperatures of the polystyrene on the AlN concentration and polystyrene particle size has also been studied. The experimental CTEs of composites have been compared with Kerner, Turner and Thomas models. The Thomas expression more closely matches the behaviour of polystyrene-AlN composites.