Fabrication and Physical Properties of Polycaprolactone/starch Blends with Corn Based Coupling Agent

Polycaprolactone (PCL) is being developed as the material of scaffolds for tissue engineering [1]. PCL is considered having fair mechanical properties and characteristics of potentials for load bearing applications, including cardiovascular, dental, and musculoskeletal [1-4]. Yet, its implementation faces some issues, e.g. inadequate mechanical properties, bioresorbability, and hydrophilicity [1,5]. Possible way in an attempt to address these issues is by compounding with other biocompatible materials, and starch is of interest. Immiscibility is an issue in blending starch to PCL. It leads to deteriorating mechanical properties and may affect the blend’s overall performance. Considering the intended applications, options are limited in compatibilizing these constituents where any substance to be incorporated into the blend should also be biocompatible. Previous studies for compatibilizing PCL and starch reported the use of predried starch [6], chlorinated starch (by using methanesulfonylchloride in dimethylformamide) [7], glycidyl methacrylate [8], and plasticizer [9]. The use of those compatibilizing agents resulted some improvements on physical properties of the PCL/starch blends but did not solve the immiscibility problem. In the purpose of similar attempt to address the issue, this study proposes the use of zein, a prolamine protein from corn. Zein is amphiphilic, having affinity for both polar and non-polar groups [10]. Zein was used as coupling agent for natural fiber/thermoplastic composite and resulted in enhanced mechanical properties [11], an indication of improved miscibility between its constituents. This potential of zein as coupling agent is expected to be exhibited for PCL/starch blends in the forms of improved physical properties and compatibility with bone cells during short term in vitro evaluation.