Poly(lactic-co-glycolic acid) Networks with Dynamic Covalent Bonds: Synthesis and Characterization

Poly(lactic- co -glycolic acid) (PLGA) is an aliphatic polyester that degrades under environmental conditions making it interesting for replacing microplastic creating polyolefins in packaging and agricultural applications. However, linear PLGA exhibits unfavorable thermomechanical properties for use. Therefore, synthetic aspects, characterization, and reprocessing ability of PLGA in the form of dynamic covalent networks are studied in the present work. The dynamic covalent networks were synthesized from short-chain four-armed star-shaped PLGA with hydroxy end groups and 4,4′-methylene diphenyl diisocyanate as a cross-linker. Tin octanoate was used as a catalyst to promote the associative exchange reactions at elevated temperatures. The synthesized networks with dynamic bonding and debonding are insoluble in common organic solvents, have enhanced the thermomechanical properties, and have maintained the possibility of thermal reprocessing and recycling like thermoplastics.