FUNCTIONALIZATION OF POLY(L-LACTIDE) MACROMONOMERS BY RING-OPENING POLYMERIZATION OF L-LACTIDE INITIATED WITH HYDROXYETHYL METHACRYLATE ALUMINIUM ALKOXIDES

摘要

End-functionalized hydroxyethyl methacrylate macromonomers of poly(L-lactide) (HEMA-PLA) were synthesized by the ring-opening polymerization of L-lactide (LA), using mono- and trihydroxyethyl methacrylate-aluminium alkoxides as initiators. The polymerization carried out in toluene at high vacuum and 60 degrees C presented a living character, giving rise to the formation of a linear polymer without cyclization side reactions. After hydrolysis of the active growing centres with dilute HCl, one hydroxyl group was formed at the end of the polymeric chains. To study the structural characteristics of the end-groups, macromonomers of relatively low molecular weight were obtained by using the mono- and tri-HEMA-aluminium alkoxides at a low ratio of [LA]/[AI]. The polymers obtained were analysed by Fourier-transform infra-red and H-1 nuclear magnetic resonance spectroscopies, taking into consideration the signals of a low-molecular-weight model compound, 2-acetyloxyethyl methacrylate, which reproduces the structure of the HEMA functional end-group of the PLA macromonomer. [References: 26]