Influence of the presence and amount of metal nanoparticles on the thermal and mechanical properties of iPP/soft paraffin wax phase change materials for thermal energy storage

[摘要] Nanocomposites based on iPP and an iPP/wax phase change blend with Ag nanoparticles werestudied. The aim of this study was to correlate the thermal and electrical conductivity, as well asdynamic mechanical properties, with the morphology of the samples prepared using quenchingin ice water and slow cooling from the melt, as well as different nanoparticle contents.Morphological analysis of the iPP/Ag nanocomposites showed that the Ag particles were welldispersed in the polymer, and formed nucleation centres for the crystallization of iPP. In theiPP/wax/Ag nanocomposites they were also well dispersed, but in the wax phase in between theiPP spherulites. The extent of filler agglomeration increased with increasing filler contents inboth iPP and the iPP/wax blend. The Ag particles, whether in the iPP or wax phase, had littleinfluence on the crystallinities and melting temperatures of iPP samples, even at higher fillercontents. The presence Ag particles in iPP had little influence on the modulus of the iPP, but thepresence of both wax and Ag particles significantly improved the modulus of these phase changenanocomposites. The thermal and electrical conductivities of the samples more significantlyimproved when both wax and Ag were present. With increasing Ag particle contents in bothiPP/Ag and iPP/wax/Ag, the thermal conductivities increased, but leveled off at higher fillercontents, while the electrical conductivities continuously increased with increasing fillercontents. The slowly cooled samples had higher crystallinities than the quenched samples andtherefore the slowly cooled samples were more thermally conductive than the quenched samples.

[发布机构] University of the Free State