Experimental validation of the Knudsen effect in nanocellular polymeric foams
DUMON, Michel
Laboratoire de Chimie des Polymères Organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
< Réduire
Laboratoire de Chimie des Polymères Organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
Langue
en
Article de revue
Ce document a été publié dans
Polymer. 2015, vol. 56, p. 57-67
Elsevier
Résumé en anglais
This paper is focused on demonstrating that it is possible to reduce the thermal conductivity of polymeric foams by reducing the average cell size below the micron. For this purpose, a wide set of samples with cell sizes ...Lire la suite >
This paper is focused on demonstrating that it is possible to reduce the thermal conductivity of polymeric foams by reducing the average cell size below the micron. For this purpose, a wide set of samples with cell sizes from 90 nm to 100 gm and relative densities from 0.12 to 0.6 has been produced and analyzed. In addition, a characterization procedure that allows identifying independently some of the heat transfer mechanisms in polymeric foams has been developed. As a result, it has been demonstrated that Knudsen effect takes place in nanocellular polymeric foams, being this effect very positive to reduce the overall heat transfer. Through the understanding of the underlying mechanisms it has possible to model the thermal conductivity behavior of these materials in the entire range of cell sizes, and overall porosities. It has been proved that the reduction of the cell size has an effect on the thermal conductivity through the solid phase, this contribution is reduced due to an increment of the tortuosity of the cellular structure and/or a confinement effect in the polymeric matrix.< Réduire
Mots clés en anglais
AEROGELS
POLYOLEFIN FOAMS
BLOCK-COPOLYMERS
Nanocellular foams
Knudsen effect
Thermal conductivity
PRESSURE CARBON-DIOXIDE
THERMAL-CONDUCTIVITY
CELLULAR STRUCTURE
SUPERCRITICAL CO2
HEAT-TRANSFER
METHACRYLATE
TRANSPORT
Origine
Importé de halUnités de recherche