Bulk polymerization of lactides initiated by aluminium isopropoxide, 3a). Thermal stability and viscoelastic properties

The thermal stability of poly(L-lactide) and L/D-lactide stereocopolymers polymerized in bulk with aluminium isopropoxide as initiator was investigated by thermogravimetric analysis, and time and température dependence of molecular weight and polydispersity. Compared to poly(L-lactide) prepared with stannous octoate as catalyst, the thermal stability of polylactides is remarkably enhanced when the ring-opening polymerization is initiated by aluminium alkoxide. Ultimate mechanical properties and viscoelasticity of these melt-stable thermoplastics have also been studied in relation to the polyester enan-tiomeric composition.