CELL STRUCTURE - THERMAL CONDUCTIVITY RELATIONSHIP OF THE POLYURETHANE AND POLYSTYRENE FOAMS

摘要

The low thermal conductivity (λ-value) of cellular plastics is one of their most important property. The total thermal conductivity of various foams at different average temperature were measured. The lambda values of different cellular plastics such as rigid and flexible polyurethane foams modified with rapeseed oil-based polyol, expanded and extruded polystyrenes have been compared. Various raw materials and technologies for manufacturing foams may be applied and therefore they have different morphology. Moreover, the structure diversity of the same material type was achieved by the changes of foaming conditions and use of various size beads in the case of expanded polystyrene. The anisotropy index of cells were estimated for the investigated foams and influence of this parameter on thermal conductivity at different temperatures have been discussed.