(556d) Hydrolytic Degradation Studies of Renewable Copolymers

Hydrolytic degradation behavior as a function of pH, time, and temperature has been studied in novel anhydride and ester renewable copolymers. The degradation rates of these copolymers will influence their potential use as a commodity polymer or biomaterial. The incorporation of both anhydride and ester bonds in the polymer backbone allows for better control of degradation with anhydride bonds hydrolyzing quickly and ester bonds hydrolyzing at a considerably slower rate. From a previous study, copolymers of 1,3-propanediol and malonic acid (PDO-MA) and 1,3-propanediol and itaconic acid (PDO-IA) were synthesized using aluminum chloride at 155 °C. Water absorption and polymer degradation were monitored using gravimetric analysis and contact angle goniometry as a function of pH, aging time, and temperature. Changes in chemical composition of these renewable copolymers were studied under the aging conditions with Fourier transform infrared spectroscopy (FTIR) by monitoring the qualitative and quantitative changes in the presence of anhydride and ester functionality. The changes in molecular weight and polydispersity index were monitored by gel-permeation chromatography (GPC). Surface Contact Angle (SCA) measured changes in surface energy with time and related to changes in molecular weight and chemical composition.