Physical interactions in macroporous scaffolds based on poly(ɛ-caprolactone)/chitosan semi-interpenetrating polymer networks

Polycaprolactone (PCL) and chitosan (CHT) are immiscible polymers. However, biodegradable porous scaffolds of both polymers were obtained by combining different techniques based on the synthesis of semi-interpenetrating polymer networks (SemiIPNs) and melt processing. SemiIPNs were prepared through simultaneous precipitation of the polymer blend (PCL/CHT) and subsequent crosslinking of chitosan with tripolyphosphate (weight fractions of CHT up to 30 wt.%). High porosity PCL/CHT scaffolds with open pore structure and good interconnectivity were obtained. Mechanical properties, evaluated by dynamic-mechanical analysis, decrease as porosity increases. The physical interactions between functional groups of CHT and carbonyl groups of PCL were assessed by FTIR, the shifting of the main relaxation of PCL towards high temperatures as the fraction of CHT increases as well as the evolution of the thermal properties of the system.