Effect of interface on thermal conductivity of polymer composite

The thermal conductivity of alumina particle filled polystyrene was characterized at different temperatures. A silane coupling agent, γ-glycidoxypropyltrimethoxy silane (GPS), was applied to functionalize the surface of alumina filler, in an attempt to investigate the effect of polymer/filler interface on composite thermal conductivity. Thermal conductivity measurements at different temperatures showed that the addition of 10 wt% alumina filler can enhance the thermal conductivity by about 23%, and the functionalization of alumina particle using silane coupling agent can increase the thermal conductivity by another 6.5%. Both 85°C/85%RH temperature/humidity aging and -50°C ∼ +80°C thermal shock testing exerted almost negligible effect on the composite conductivity, indicating the polymer/filler interface was stable and no interface debonding occurred for the specific alumina polymer composite system studied.