Insights from molecular dynamics simulations for interfacial effects between polylactic acid and wood cell wall constituents

Abstract

• The interface structure between wood cell wall components and polymer is studied. • Molecular insights into the differences in the adhesion behavior of polymers on the surface of wood cell wall component. • Provides insights for the structural design of biomass composites. Knowledge of the interfacial structure from an atomic or molecular perspective helps to optimize the manufacturing of nanocomposite materials with bottom-up structural design and controls the performance more effectively. In this work, molecular dynamics simulation was used to study the composition, structure, and mechanism of interactions at the interface between wood cell wall constituents (cellulose, lignin, and hemicellulose) and polylactic acid (PLA). Results showed that the interfacial adhesion between the components and polymer was affected by the surface structure and the diffusion and aggregation of the polymer. Compared with the crystalline surface, the amorphous structure could achieve greater bonding energy and lower surface energy, and thus improving the dispersibility of fillers in the polymer matrix. An orderly arrangement and denser packing of the polymer were observed on the crystalline surface and the diffusion capacity of the polymer was reduced due to reduction in local free volume.