Submitted to: Materials Chemistry and Physics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/23/2011
Publication Date: 4/14/2011
Citation: Holser, R.A. 2011. Degradation rates of glycerol polyesters at acidic and basic conditions. Materials Chemistry and Physics. 128(1-2):10-11. Interpretive Summary: Polymers prepared from renewable materials by a non-polluting process were investigated to measure the rate of degradation at different environmental conditions and determine the nature of the degradation products. The results showed that the polymers degraded rapidly at acid, base, or neutral pH conditions into the original components. Polymers made from blends of glycerol (a co-product generated during the conversion of vegetable oil to biodiesel fuel), citric acid, and adipic acid were completely degraded in 45 days. These polymers have numerous applications in agricultural, environmental, and pharmaceutical products where a temporary structure is needed that can function as a barrier, scaffold, or delivery matrix and degrade into simple organic compounds. These compounds can be left in the environment as a soil amendment, collected and recycled, or metabolized by organisms depending on the application.
Technical Abstract: Polyesters prepared from 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 provide a market 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 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.