A study on the effects of lignocellulosic biomass components on the interactions and thermal conductivity of stearic acid: Molecular dynamics simulation

Abstract

Lignocellulosic biomass, with its sustainability, wide availability, and low cost, has become an ideal choice for supporting phase change materials (PCMs) and has been widely applied in various fields. Since lignocellulosic biomass mainly consists of three components, cellulose, hemicellulose, and lignin, and these components have distinct effects on the thermal properties of composite PCMs, this study uses stearic acid (SA) as a model substance and employs molecular dynamics simulations to systematically investigate the interactions between these components and SA and their impact on thermal conductivity. By analyzing the radial distribution function, radius of gyration, mean squared displacement, diffusion coefficient, and the binding energies between cellulose, hemicellulose, lignin, and SA, the study reveals the different roles each component plays in the adsorption of SA and elucidates the key mechanisms underlying the differences in the loading capacity of lignocellulosic biomass in composite PCMs. The results show that cellulose plays a critical role in the loading of SA, with a binding energy of -230.7 J/mol, significantly higher than that of hemicellulose and lignin. In addition, hemicellulose exhibits outstanding performance in enhancing the thermal conductivity of composite PCMs. Specifically, the thermal conductivity of the SA/hemicellulose system is 0.28 W/(m·K), which is 22 % higher than that of the SA/cellulose system and 47 % higher than that of the SA/lignin system. This study provides an important theoretical foundation for optimizing the design and application of lignocellulosic biomass-based composite PCMs.