Synthesis and thermal properties of novel star-shaped poly(L-lactide)s with starburst PAMAM-OH dendrimer macroinitiator

The starburst PAMAM-OH dendrimer (generation 3) as macroinitiator for the synthesis of star-shaped polylactides in the presence of stannous octoate was investigated. Effects of molar ratios of monomer to initiator, monomer to catalyst, monomer conversion, and reaction temperature on polymerization were studied. It is found that 16-21 polylactide arms can be attached to the surface of dendrimer initiator, and the molecular weight of polylactides can be controlled by variation of molar ratios of monomer to initiator and polymerization time. Thermal analysis indicates that the star-shaped polylactides possess lower glass transition temperature, melting point, crystallinity, and maximum decomposition temperature than those of linear polylactide. (C) 2002 Elsevier Science Ltd. All rights reserved.