The invention relates to the field of functional materials, in particular to a preparation method and application of a kapok-based porous material with a
radiation cooling function. According to the method, natural kapok short fibers are subjected to constant-temperature alkali treatment to peel off
wax on the
surface layer, a delignification reaction is carried out with an acidic
sodium chlorite solution, and the kapok-based porous material with the
radiation cooling function is obtained. And the coarse reticular
cellulose structure in the material is thoroughly exposed. The treated active fibers and nano
cellulose are subjected to high-strength blending in a water phase, nano fibrils are guided to deeply penetrate into gaps of a micron-sized kapok skeleton, and a tightly-meshed composite
system is constructed. And dropwise adding an organosiloxane
reagent into the acidic
liquid phase to complete surface hydrophobic modification, and carrying out controlled low-temperature setting and vacuum freezing sublimation
dehydration to form the three-dimensional base material containing a micro-nano dual-pore network. The material can effectively reflect
sunlight and emit heat
radiation through an
atmosphere window, zero-energy-consumption passive radiation cooling is achieved, and meanwhile the excellent heat insulation performance is achieved.