Effect of carbon nanotubes on the thermal conductivity of flexible cellular polymers based on polyurethane

Abstract

The main aim of this research is to increase the thermal conductivity of flexible PU foams by the addition of single wall carbon nanotubes (SWCNT). Four techniques to maximise dispersion of nanotube in different mediums before its addition to a flexible Polyurethane (PU) matrix have been used. Semiempirical obtained solid conductivity values for all studied samples have been compared with theoretical models (mixing rule and Kapitza models), to assess whether filler percolation did take place or not. The effect of dispersion technique and percolation network in cellular structural changes has also been analysed. Net obtained thermal conductivity gain, directly attributed to addition of SWCNT is 25,6 %, referred to a pure flexible foam.