Interfacial improvement of poly (lactic acid)/tannin acetate composites via radical initiated polymerization

Abstract A wholly bio-composite based on poly (lactic acid) (PLA) and tannin acetate was successfully prepared via in situ reactive extrusion using dicumyl peroxide (DCP) to improve interfacial adhesion. The composites based on PLA and tannin acetate with high acetylation degree exhibited increased molecular weight as compared with reactive extruded PLA, together with the improvement of Young’s modulus and tensile strength. The rheology results showed that reactive extruded PLA/tannin acetate composites exhibited increased complex viscosity and modulus storage, indicating the strong interfacial adhesion of PLA and tannin acetate. Besides, Glass transition temperature, thermal stability, and crystallinity degree were all enhanced as a result of better interaction by radical initiated polymerization. From contact angle data, free radical extruded composites had a more hydrophobic characteristic compared with PLA, which might be interesting for food packaging application. This approach opens up a pathway to diversify the applications of tannin as a component for bio-composite preparation.