Aliphatic polyesters prepared by the ring opening polymerization of lactones and lactides, are versatile polymers having good hydrolyzability, mechanical properties and biocompatibility. These characteristics make them a leading material in biomedical and pharmaceutical industries as a resorbable implant and a vehicle for controlled drug delivery. An extensive research effort has been made to develop new initiators, catalysts for the ring opening polymerization of cyclic esters. Many effective initiators based on alkali metals, metal oxides have been developed for anionic polymerization of lactones. The main objectives of this project were to develop a novel catalyst by utilizing fully biocompatible and non-toxic reagents for the synthesis of polycaprolactone (PCL) by ring opening polymerization of cyclic esters at reasonably low temperature and a synthesis of hybrid silica nano-composite for biomedical applications and its characterization. Silica and dry calcium hydride reagents were used to successfully prepare heterogeneous catalysts for the ring opening polymerization of cyclic ester monomer å-caprolactone at reasonably low temperature of 100 oC. Two kinds of catalyst were prepared with non-functionalized and silane functionalized silica. The GP silane functionalized silica catalyst showed higher activity and higher product yield as compared to non-functionalized catalyst during polymerization at the same temperature. The in-situ polymerization kinetics of both reactions was studied using Raman spectroscopy. A silica based nano-composite was also synthesized which has a potential application in bone tissue engineering and possible drug delivery. The synthesized polyester and hybrid silica nano-composite were characterized with different analytical techniques to confirm required product formation.
| Identifer | oai:union.ndltd.org:ADTP/265788 |
| Date | January 2008 |
| Creators | Khan, Javaid Hasan |
| Publisher | Queensland University of Technology |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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