Mechanical properties of porous photo-crosslinked poly(trimethylene carbonate) network films

Tissue engineering scaffolds require high porosity and optimized pore sizes to allow cell seeding, -adhesion and –proliferation, and tissue ingrowth. However, porosity affects the mechanical properties of the scaffolds to a large extent. Usually, these properties are only assessed in compression experiments. Here we investigate the effect of the pore characteristics on the tensile properties of photo-crosslinked poly(trimethylene carbonate) network films that were prepared by a method involving salt leaching and by stereolithography. Particulate leaching is a conventional method to obtain porous structures, while stereolithography is an additive manufacturing method that provides the benefit of control over pore architecture and allows for complex geometries to be prepared. The tensile properties of the porous network films were indeed much affected by porosity. The elasticity modulus of porous network films decreased with increasing porosity. This decrease appears to be independent of pore size. For a given porosity, the values of the elasticity moduli, maximum tensile strengths and toughness of porous poly(trimethylene carbonate) network films prepared by stereolithography were slightly higher than those of porous network films prepared by the salt leaching method. This may be due to different amounts of diluent used while preparing the networks by the different methods. In addition, the presence of salt in the material during crosslinking appears to result in a less efficient crosslinking process.