Characterization of the viscoelastic properties of poly(ε-caprolactone)-hydroxyapatite microcomposite and nanocomposite scaffolds

In bone tissue engineering, the mechanical properties of the scaffolds need to be sufficiently high to prevent material failure when bearing loads. To strengthen the scaffold, various composites have been proposed in the literature, including poly(e-caprolactone) with hydroxyapatite (HA). In this study, the processing of this composite using the gas foaming/salt leaching technique is examined. The control of scaffold properties by varying the processing parameters was first investigated. Then, the change in properties, with a focus on the viscoelastic properties, from the varying morphology was examined. Although an increase in scaffold density and pore size increased the scaffold modulus, it did not significantly affect the viscoelastic properties. Furthermore, the addition of HA decreased the scaffold modulus and increased the loss factor of the composite scaffolds. The more viscoelastic behavior is believed to be due to the more open structure that was created. When tested in a water bath to better simulate the physiological environment, the mechanical properties decreased by up to 85%, and the scaffolds also behaved more viscoelastically. The comparison of the scaffold properties shows the differing behavior of the scaffolds in dry and wet conditions. Hence, the environment of testing should be more carefully considered when designing experiments. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineers