Block Copolyesters Based on Poly(lactide) and Aromatic-Aliphatic Polyesters of the AA/BB type and Acid Functionalized Poly(lactide) and Poly(ester-urethane)s Therefrom

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Polymers and High Performance Materials

First Advisor

Robson F. Storey

Advisor Department

Polymers and High Performance Materials


Aromatic-aliphatic poly[L-lactide-b -(ethyleneoxyethylene terephthalate-co -adipate)-b -L-lactide] triblock copolymers were synthesized and characterized. Hydroxy-telechelic poly(ethyleneoxyethylene terephthalate-co -adipate) (PEOETA) was first prepared via polycondensation and then utilized as an initiator for the ring opening polymerization (ROP) of L-lactide (LLA) in the presence of stannous octanoate (Sn(Oct) 2 ). Formation of the block copolymer was confirmed by 1 H NMR spectroscopy, GPC, DSC and AFM. The polymerization rate induced by the PEOETA macroinitiator was comparable to that of a small molecule initiator. The mechanical and degradation properties failed to meet project objectives; therefore we focused more attention to the modification of α-hydroxy acid polymers for use in the creation of degradable polyurethanes. Linear poly(D,L-lactide) containing a single pendant carboxylic acid group (BHMBA-PDLLA) was synthesized via ring opening polymerization (ROP) of D,L-lactide using 2,2-bis(hydroxymethyl) butyric acid (BHMBA) as an initiator. Characterization of the BHMBA-PDLLA using NMR spectroscopy and gel permeation chromatography confirmed the presence of the pendent carboxylic acid group and provided evidence of a linear architecture. Degradation studies were performed on BHMBA-PDLLA polyesters by immersion into aqueous buffered solution (7.4 pH) held at a constant temperature of 37°C. Complete degradation of the BHMBA-PDLLA occurred at times much earlier than those of the controls. These poly(α-hydroxy acid) polymers have shown promising degradation results when chain-extended using L-lysine diisocyanate methyl ester as the chain-extending agent.