Synthesis and characterization of a novel polymer-ceramic system for biodegradable composite applications

The objective of this study was to develop a biodegradable polymer resin that could be used for the fabrication of an interpenetrating phase composite (IPC) made of porous calcium polyphosphate (CPP) and an organic polymer resin. The resin was synthesized from a polycarbonate-based divinyl oligomer and monomers containing ionic groups. The physical and chemical properties of the polymer resin and polycarbonate-based divinyl oligomer were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and swelling studies. The in vitro degradation of the polymer resins was assessed using cholesterol esterase in a buffer solution at 37 degrees C for 3 weeks. Scanning electron microscopy of the degraded samples indicated that the hydrolysis of the resin was catalyzed by the enzyme. The relative interfacial shear strength between the polymer resin and the CPP ceramic was studied using a microbond test. The addition of ionic groups into the polymer resin chains appeared to improve the chemical bonding between the polymer and the CPP. Preliminary mechanical properties of the IPC were investigated by determining bending strength using a three point bending test. The data showed a sevenfold increase in strength over that of the monolithic CPP, and the addition of more ionic groups into the resin led to a higher bending strength for the newly formed CPP/polycarbonate resin system. Sample cross sections of the IPC examined using scanning electron microscopy suggested that the resin had infiltrated almost all of the pores of the CPP. The results of this study indicate that the IPC could potentially be used for fabricating novel biodegradable load-bearing implants.