Thermal Diffusion Properties of TEMPO-Oxidized Cellulose Nanofiber Films

Fibrous TEMPO-oxidized cellulose sodium salt (TOC-Na) and TEMPO-oxidized cellulose nanofiber sodium salt (TOCN-Na) were prepared. Counterions of TUC-Na and TOCN-Na were exchanged to copper, aluminum, and silver ions to form TOC-M and TOCN-M (M: metal). TOC-M sheet is were prepared from TOCMiwater 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.