Affiliations: Biomaterial and Tissue Engineering Centre (BTEC), Academic Division of Surgical & Interventional Sciences, University College London, London, UK | Department of Mechanical Engineering, University College London, UK | Great Ormond Street Hospital for Children and Institute of Child Health, London, UK
Note: [] Address for correspondence: Mohan J. Edirisinghe, Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK. Tel.: +44 207 679 3942; Fax: +44 207 388 0180; E-mail: m.edirisinghe@ucl.ac.uk.
Abstract: A non-biodegradable polyhedral oligomeric silsesquioxane (POSS) nanocomposite biopolymer has been developed for fabrication of medical devices and for tissue engineering human organs. The polymer in solution, containing 2 wt% of POSS, has been synthesized, characterized and investigated to determine its key rheological properties. Thus, the variation of shear stress and viscosity as a function of shear rate has been determined at ambient temperature to estimate yield stress and the index of pseudoplasticity, respectively. The temperature dependence of viscosity and the effect of ageing on the viscosity of the polymer have also been investigated. Results are compared with those of a conventional polycarbonate urethane (PCU) polymer solution. The POSS-PCU polymer solution shows near-Newtonian behaviour in the shear rate range to 1000 s−1, having an apparent viscosity of ~3000 mPa s and a pseudoplasticity index of 0.90, decreasing slightly as the polymer solution is aged over 9 months. The temperature dependence of viscosity of the POSS polymer is extremely low and does not change with ageing but the yield strength increases from 2.7 Pa to 8.3 Pa.
