Optical properties of freeze-dried partial delignified balsa wood

Abstract Radiative cooling (RC) is natural phenomenon in which an object passively cools itself by highly radiating mid-infrared waves to the cold outer space. The delignified wood (DW), lignin molecules are removed from wood, shows promising performance of daytime radiative (DRC). However, DW usually hot-pressed during oven drying process results collapse cell walls. This problem hinders application as a scaffold for polymer-wood composite. In this study, we have fabricated partial (PDW) with combination delignification and freeze-drying processes. has been performed boiling hydrogen peroxide (H 2 O ) solution renewable system. It found that PDW turns white colour after 30 hours time. ATR-FTIR spectroscopy confirms altered process, strong emission peaks due molecular vibrations cellulose appear atmospheric windows. averaged solar absorptivity PDW, measured diffuse reflectance UV-Vis-NIR spectroscopy, equal 11% about three times lower than wood. relative drop radiation absorption maximum value at wavelength 529 nm full-width-at-half-maximum to.