Thermal Properties and Degradation Behavior of Linear and Branched Poly(L-lactide)s and Poly(L-lactide-co-glycolide)s

Poly(lactide)s and poly(lactide‐co‐glycolide)s with different number of arms are synthesized from L‐lactide and glycolide monomers using stannous(II) 2‐ethylhexanoate and alcohols containing 1, 2, 25, and 51 hydroxyl groups. 1‐dodecanol is used to produce the 1‐arm polymer, poly(ethylene glycol) for the 2‐arm polymer, and polyglycidols of appropriate molecular weight are used to initiate the 25‐ and 51‐arm branched polyesters. The polymers are characterized by 1H NMR and GPC. The thermal properties of the polymers are studied using DSC. Their degradation behavior is indestigated using a combination of thermogravimetry, FTIR spectroscopy, and isoconversional kinetic analysis. The synthesis and thermal properties of polylactide and poly(lactide‐co‐glycolide) polymers of potential pharmaceutical and/or medical relevance is reported. The polymers are linear and branched containing 1, 2, 25, or 51 arms. The degree of branching affects the crystallinity, melting, and glass transition of the polymers, but not the mechanism and kinetics of their degradation.