Degradation rates of glycerol polyesters at acidic and basic conditions

Polyesters prepared from the reaction of glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers can provide a marketable product for glycerol that is generated during biodiesel production. The polyesters were prepared without catalyst or solvent and produced water as co-product of the condensation reaction. Degradation rates for five glycerol polyester blends were determined from the amounts of the component acids released. All of the polyesters degraded rapidly to the component acids and glycerol. Polyesters exposed to acid solutions degraded 40.2% per day. Polyesters exposed to base solutions degraded 42.0% per day and polyesters exposed to neutral solutions degraded 37.5% per day. Applications for these materials exist in agricultural, environmental, and biomedical engineering products.