Detection and control of cyclic esters in biodegradable polyesters

The techniques for the detection and control of cyclic esterification (CE) in biodegradable polyesters are presented. It is pointed out that CE can be extracted by extraction or migration and then detected using GC-MS or LC-MS depending on their volatility, with LC-MS techniques being more commonly used due to the generally poor volatility of CE. CE was detected in several typical biodegradable polyesters such as poly(lactic acid) (PLA), poly(butylene succinate) (PBS) and poly(butylene adipate-terephthalate) (PBAT) with repeating units less than 10; both the improvement of the polymerization process and the use of organic solvents to wash the biodegradable polyester particles can effectively reduce the content of CE, and the washing strategy is relatively more convenient and efficient.