Calcium silicate/polyvinyl/chitosan/alginate-based bioceramic slurry for 3D printing of scaffolds: Interfacial interactions – Mechanical properties relationship

Abstract

At present, there are few studies investigating the influence of mechanical properties of binders on bioceramic slurry at the micro- and macroscopic levels. In this work, we used molecular dynamics (MD) simulations and experiments to investigate the influence of mechanical properties of polyvinyl alcohol (PVA), chitosan (CS), and sodium alginate (SA) polymers on calcium silicate (CSi, CaSiO3)/binder bioceramic slurry and to choose the most suitable binders to prepare CSi/binder slurry. It was found that PVA demonstrated excellent stiffness, ductility, toughness, solubility, and low shear thinning. The formation of large number of hydrogen bonds (HBs) at the CSi/PVA interface results in strong interfacial bonding and higher compressive strength of CSi/PVA slurry while other binders suffer low solubility, higher shear thinning, poor stiffness, and ductility problems. From the calculated mechanical parameters, interfacial binding energy, and compressive tests, it was found that the slurry prepared by CSi and 10 PVA (mixing ratio: 1:0.9) demonstrate the best mechanical properties, a compressive strength of 7.3 MPa, thus, meeting the requirements of compressive properties of cancellous bone defects. The simulation results were supported by experiments. This study provides a theoretical and experimental guide for binder selection in bioceramic slurry and the design of future binder composites.