Trickily designed copolyesters degraded in both land and sea - confirmed by the successful capture of degradation end product CO2

Abstract

To remediate the poor seawater-degradability of existing biodegradable materials, glycolic acid (GA) is installed into poly(butylene succinate) (PBS) backbone to synthesize a series of random copolyesters called poly(butylene succinate-co-glycolate) (PBSG), aiming to take advantage of the fast hydrolysis of GA units to accelerate the previous hydrolysis of copolyesters in seawater, thereby inducing the final biodegradation process. These materials possess good mechanical properties and processability. Most importantly, their biodegradation is significantly enhanced in not only compost but also seawater, owing to the newly generated readily hydrolyzable points in main-chain. When PBSG splines are exposed to natural seawater for 433 days, rapid loss of mechanical properties, significant drop of molecular weight and weight loss are observed. A highly sensitive system for detecting polymer degradation in seawater is designed and used for the first time for determining end-product CO2. A first record mineralization rate of 50% in seawater after 365 days is achieved for PBSG30 to confirm the occurrence of biodegradation, while PBS shows no obvious sign of degradation. PCR technology is used to identify dominant bacterium involved in seawater degradation process. Sneathiella and Microbacterium are identified for the first time as the specific bacteria for degrading this kind of polyesters in marine.