Biomass-based porous composites with heat transfer characteristics: preparation, performance and evaluation-a review

Porous materials have unique network structure, which are composed of interconnected or closed pores, with low relative density, high specific surface area and appropriate porosity. Biomass materials originated from nature, exhibiting good biocompatibility, excellent environment-friendly, non-toxicity, easy to biodegradation and alterable mechanical properties, have attracted more and more attention. Nowadays, the biomass-based porous composites with proteins, polysaccharides or lignin have shown broad application prospects in heat insulation, heat conduction and heat dissipation, wave absorption and sound absorption due to their unique pore structure and tunable thermal conductivity. Herein, the main features of different kinds of biomass materials, liking proteins (collagen, keratin and silk fibroin), polysaccharides (cellulose, chitosan and starch) and lignin are briefly introduced at first. Then, the preparation technologies of biomass-based porous composites, including spinning, foaming, sol-gel, 3D printing and different drying methods, as well as their application in the field of thermal management, are emphatically summarized. Furthermore, the factors that affect the thermal conductivity of the porous composites are also discussed, including pore parameters, intrinsic properties of the components, and the application environment. Subsequently, methods for evaluating heat transfer performance of porous materials are briefly summarized, including the steady-state method, transient method and temperature-modulated differential scanning calorimetry method. Finally, we suggest to further explore and improve the preparation methods of biomass-based porous composites suitable for practical application in the field of thermal management, so as to make them simpler, cheaper, more efficient and more environmentally friendly, as well as suitable for mass production.