THERMAL-PROPERTIES OF PURE AND DOPED (POLYVINYL-ALCOHOL) PVA

Films almost-equal-to 350 mum of poly(vinyl-alcohol) composites, containing copper (Cu), aluminium (A1) and iron (Fe), metallic powder very fine, were prepared by a casting method. Thermal conductivity, phonon velocity, mean free path and specific heat were studied. The pure sample of PVA has a lower values of thermal conductivity than that which are doped with metals. For all samples the thermal conductivity K increases up to a certain temperature T(gg) (120-160-degrees-C) and then decreases with temperature. The specific heat increase with temperature up to almost-equal-to 120-degrees-C and above 120-degrees-C is nearly independent on temperature. The pure sample of PVA has small values of mean free path (L) almost-equal-to 0.2 angstrom at room temperature, but for PVA+ metals L almost-equal-to 2.0 angstrom. The phonon velocity of pure PVA is larger than that of PVA containing metals.