Thermophysical characterization of Posidonia Oceanica marine fibers intended to be used as an insulation material in Mediterranean buildings

Abstract

The present work focuses on the study of the thermophysical properties of Posidonia Oceanica natural fibers in order to investigate the potential of their use as loose-fill thermal insulation material in the Mediterranean construction. 24 samples were prepared. Bulk densities were varied from 17 kg m−3 to 155 kg m−3. Chemical alkali treatments with various conditions were applied to these fibers. The influence of treatments and of density on morphological and thermophysical properties of samples was evaluated. The surfaces were examined by using scanning electron microscopic. The thermal measurements were performed with the Hot Disk thermal constants analyzer. Results have shown that thermal conductivity decrease when density decreases until an optimum. After that, it increases as the density is reduced. Furthermore, regarding thermal conductivity, it was found out that the effect of chemical treatment is not significant mainly at the low densities. A very slight improvement was found at high densities with treated fibers, mainly the treatment that consists of immerging fibers twice in 2% sodium hydroxide solution during 2 h at 80 °C. Higher mass heat capacity was observed with this same treatment.Additionally, it was revealed in this study that Posidonia-Oceanica fibers have thermal conductivity and thermal diffusivity close to conventional insulation materials and higher mass heat capacity that reached 2533 J kg−1 K−1.