Biodegradabilities of various aliphatic polyesters in natural waters

Eight types of aliphatic polyesters were prepared by both biosynthetic and chemosynthetic methods, and their biodegradation tests were carried out at 25 degrees C for 28 days under aerobic conditions in different environmental natural waters. Biodegradabilities of melt-crystallized polyester films were evaluated in a temperature-controlled reactor by monitoring the time-dependent changes in the biochemical oxygen demand (BOD) and weight loss (erosion) of polyester film. The biosynthetic poly(3-hydroxybutyrate-co-14% 3-hydroxyvalerate) was degraded at a rapid rate in all natural waters used, and the weight-loss and BOD biodegradabilities of the films were 100% and 78 +/- 8% for 28 days, respectively. By contrast, the films of chemosynthetic poly(ethylene succinate) were eroded completely in freshwater within 10 days, whereas the films were hardly eroded after 28 days in seawater. (C) 1998 Elsevier Science Limited. All rights reserved.