Thermal diffusion properties of TEMPO-oxidized cellulose nanofiber films

Abstract

Fibrous TEMPO-oxidized cellulose sodium salt (TOC-Na) and TEMPO-oxidized cellulose nanofiber sodium salt (TOCN-Na) were prepared. Counterions of TOC-Na and TOCN-Na were exchanged to copper, aluminum, and silver ions to form TOC-M and TOCN-M (M: metal). TOC-M sheets were prepared from TOC-M/water dispersions by filtration, and TOCN-M films were prepared from TOCN-M/water dispersions by casting and drying. The thermal diffusivities of the TOC-M sheets and TOCN-M films were measured in terms of metal counterions. All TOC-M sheets and TOCN-M films had higher thermal diffusivities in the planar direction than thickness direction. The TOCN-M films had higher thermal diffusivities than the TOC-M sheets or commercial transparent films. In TOCN-M films, the thermal diffusivities increased in the order, TOCN-Al < TOCN-Cu < TOCN-Ag.