Antimicrobial pullulan derivative prepared by grafting with 3-aminopropyltrimethoxysilane: Characterization and ability to form transparent films

In the present work, we propose a simple and straightforward procedure to prepare antibacterial transparent pullulan films by functionalization of pullulan powder with 3-aminopropyltrimethoxysilane. The introduction of active aminopropyl groups into the pullulan polymeric backbone imparts antimicrobial activity against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). In addition, the antimicrobial pullulan maintains its filmogenic ability and the films showed reasonable mechanical properties (Young modulus of 1.8 GPa and tensile strength of 21 MPa) and improved thermal stability (increment of 10 °C on the maximum degradation temperature), opening the possibility for application in functional food packaging films and coatings.