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 carri ed out at 25 degrees C for 28 days under aerobic conditions in differe nt environmental natural waters. Biodegradabilities of melt-crystalliz ed polyester films were evaluated in a temperature-controlled reactor by monitoring the time-dependent changes in the biochemical oxygen dem and (BOD) and weight loss (erosion) of polyester film. The biosyntheti c poly(3-hydroxybutyrate-co-14% 3-hydroxyvalerate) was degraded at a r apid rate in all natural waters used, and the weight-loss and BOD biod egradabilities of the films were 100% and 78 +/- 8% for 28 days, respe ctively. By contrast, the films of chemosynthetic poly(ethylene succin ate) 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.