A novel biomass polyurethane-based composite coating with superior radiative cooling, anti-corrosion and recyclability for surface protection

Towards the irreversible increase of energy demands, the development of non-fossil, bio-renewable, and sus-tainable resources has become a necessary and important strategy. Herein, a biomass polyurethane (PU) pre -polymer derived from Jatropha oil (JO) resource was successfully synthesized. To endow this bio-PU material with desired functionalities, the hybrid nanoparticles with different proportions of barium sulfate (BaSO4) and titanium dioxide (TiO2) were incorporated into PU matrix. After UV curing treatment, the resultant composite coatings possessed superior UV blocking and infrared radiative cooling properties, where the reflectance of the optimal one reached 97.30 % in the UV (200-380 nm) region, and the maximum temperature difference of surfaces before and after loading coating was up to 20.8 degrees C as exposing 60 min under infrared irradiation, significantly reducing the heat radiation on the protected material. Besides, the coatings exhibited excellent anti-corrosion even immersing in strong acid, alkali, and salt solutions for 30 days, and the recyclability and sec-ondary use of this coating was synchronously confirmed through the repeated processing. Finally, the adhesion of these coatings on the surface protection of multiple materials was demonstrated, including metal, plastic, wood, and glass substrates. Overall, from biomass JO raw material to PU-based functional coatings, this work not only enriches the synthetic strategy of biomass polymer derived from the non-fossil resource, but also paves the way for further applications in surface protection with multi-characteristic composite coatings.