Enhancing degradability with polyanhydrides: synthesis and impact on morphology, molecular interactions, hydrophilicity and hydrolytic degradation of PLLA/PCL/CAB blend films

Abstract

The degradation of polymer-based materials is crucial for their end-of-life management, particularly in biomedical applications where controlled degradation rates are essential. Addressing this need, this study explores the incorporation of newly designed polyanhydrides (PAs) into multicomponent blends to enhance hydrolytic biodegradation. Two distinct PAs – poly[(propionic anhydride)-co-(succinic anhydride)] (PASA) and poly[(propionic anhydride)-co-(sebacic anhydride)] (PASEA) – were synthesized through melt-condensation polymerization. These PAs were then incorporated into solution blend films composed of poly(l-lactide) (PLLA), poly(ε-caprolactone) (PCL) and cellulose acetate butyrate (CAB), aiming to serve as an accelerator for the hydrolytic degradation of films. The incorporation of PASA and PASEA into the PLLA/PCL/CAB blend films resulted in the formation of phase-separated domains and a notable shift of the carbonyl frequency band in the Fourier transform infrared spectra, indicating phase separation and intermolecular packing between homopolymers in the blend system. Significant changes in the molecular weight and surface morphology of the blend films with PAs were observed after 0, 3 and 6 months of storage. These observations confirmed the role of PASA and PASEA in accelerating through surface erosion, as evidenced by the presence of craze lines at both macrophase- and microphase-separated domains. This study highlights the potential of newly designed PA additives to enhance the degradation and stability of PLLA/PCL/CAB polymer-based film. Such enhancements are valuable for designing materials with controlled degradation rates, which is particularly important in biomedical applications where precise timing of degradation within the body is essential. © 2025 Society of Chemical Industry.