Dynamic Mechanical Analysis and Hydrolytic Degradation Behavior of Linear and Branched Poly( L ‐lactide)s and Poly( L ‐lactide‐co‐glycolide)s

Abstract Linear and branched poly(lactide)s and poly(lactide‐co‐glycolide)s are synthesized using stannous (II) 2‐ethylhexanoate and alcoholic co‐initators resulting in polymers with 1, 2, 25, or 51 arms. 1‐dodecanol is used to produce the 1‐arm polymer, poly(ethylene glycol) is used for the 2‐arm polymers, and poly(glycidol)s of appropriate molecular weights are used to initiate the 25‐ and 51‐arm branched polyesters. The polymers are evaluated by melt rheology and dynamic mechanical analysis. In vitro degradation is investigated in phosphate buffer pH 7.4 at 37 °C for 28 d for moisture uptake and mass loss. Degraded samples are analyzed by gravimetry, differential scanning calorimetry, dilute solution viscometry (Cannon‐Fenske), and gel‐permeation chromatography. magnified image