Polylactones 3. Copolymerization of glycolide with L, L-lactide and other lactones

Abstract

Numerous copolymerizations of glycolide with 6-propiolactone, y-butyrolactone, 6-valerolactone and E-caprolactone were conducted either in bulk or in nitrobenzene solution at temperatures in the range of 20-150°C. Three classes of catalysts were used, namely acidic catalysts initiating cationic polymerizations, complexing catalysts operating via an insertion mechanism and true anionic catalysts. A summary of these already previously described results is presented in this work along with a detailed report on the copolymerization of glycolide and L6L-lactide. These two monomers were copolymerized in bulk at 1 0 0 or 150 C and twenty different catalysts were used in both series The molar compositions of the resultin copolyesters were determined by iH NMR spectroscopy. The possibility of "C NMR sequence analyses is discussed for all afore-mentioned copoly(1actone)s and also for L,L-lactide/€-caprolactone copoly(ester)s. DSC measurements of the glycolide/ L,L-lactide copolymers are discussed in connection with the NMR spectroscopic results. Furthermore, optical rotation measurements were conducted and it was found that the optical rotation of glycolide/L,L-lacti.de copolymers depends on their sequence. 0252-1 997/85/lJS $0.200

The preparation of monodisperse biodegradable polyester nanoparticles with a controlled size

“…This is caused by the fact that for steric reasons, lactide is kinetically and thermodynamically less polymerizable than glycolide. 26 From the 1 H-NMR-results it becomes clear that the theoretical molecular weight is indeed obtained. Furthermore, it can be seen that the polydispersity index ranges from 1.42 to 2.09.…”

More about the polymerization of lactides in the presence of stannous octoate

“…2, [8][9][10] of initiators have been successfully tested, [4][5][6] but The possibility of co-initiation by monomer and catalyst impurities was suspected, and a Lewis acid catalyzed mechanism was proposed which is tration. 2 On the other hand, it was claimed that Acetone was evaporated from the solution, and the solid residue was dried under vacuum over tin alkoxides may be formed when an alcohol is added and cause the initiation of the lactide polyseveral days too.…”

An Overview of the Synthesis and Synthetic Mechanism of Poly (Lactic acid)

“…The initial process is that the ring of the lactide activated by receiving acid proton is opened by the attack of alcohol carbonyl, and lactyl alcohol is made. Examples that trifluoromethanesulfonic acid (HOTf) and methyl trifluoromethanesulfonate (MeOTf) catalyzes ring-opening reactions of lactide or glycolide are well known [49,50].…”