Transient pulsed technique to characterize the radiative and conductive properties of bio aerogels

This work presents the development of a method dedicated to the estimation of the thermal and radiative properties of bio-based aerogels, manufactured from cellulose nanofibers. This method has been developed using a transient pulsed method, which is based on the measurements of the temperature from both the front and rear faces of the sample. A theoretical model coupling radiative and conductive heat transfers is presented in which the radiative transfers are expressed by the radiative conductivity. The sensitivity analysis shows that the radiative part of the transfer is decorellated from the conductive part, so that the thermal and radiative conductivities as well as the thermal diffusivity can be estimated simultaneously. Measurements have been compared with other experiments such as the hot plate technique and we observed that thermal conductivity has been estimated with a precision lower than 5%.