Biodegradable crosslinked polymers based on triethoxysilane terminated polylactide oligomers

Lactic acid based polymers and their copolymers are widely used in biomedical applications. Different properties are introduced by modifying the composition. In this study, crosslinked polymers were produced from DL-lactide oligomers, which were functionalised with (3-isocyanatopropyl)triethaxysilane (IPTS) and crosslinked by acid catalysis in the presence of water without the use of solvent. The polymers were characterised by fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), and their crosslinking density and compressive properties were measured. Functionalised linear and star-shaped oligomers were characterised by FTIR and DSC and also by H-1 NMR and size exclusion chromatography (SEC). According to H-1 NMR, 79-95% of the hydroxyl groups were functionalised by IPTS during the early part of the synthesis. The formation of a strong polymer network was found to require a curing temperature of at least 90 degreesC. The best mechanical properties were achieved with the oligomer initiated with 5% pentaerythritol. The properties of the polymer were then compressive yield strength 81 MPa, modulus 2260 MPa and 4.4% strain at yield point. (C) 2001 Elsevier Science Ltd. All rights reserved.