Characterization of biodegradable poly(butylene adipate-co-terephtalate)/sodium caseinate films loaded with an alkyl furanoside as antimicrobial agent

A biodegradable material was prepared by blending sodium caseinate (NaCAS) with poly(butylene adipate-co-terephtalate) (PBAT). The best composition was selected from mechanical testing of PBAT/NaCAS blends for further manufacture of a partially biobased film able to deliver a bioactive compound. From stress–strain testing, it was determined that the best mechanical properties while keeping maximum NaCAS content were obtained for 80/20 w/w PBAT/NaCAS blends plasticized with 10 % Glycerol (Gly). The surfactant octyl-β-d-galactofuranoside was used as an antitubercular agent and directly incorporated in the blend during hot mixing. The biodegradable films containing 1–5 % by weight of galactofuranoside were observed by SEM and showed crystalline structures on their surface. From X-ray diffraction studies, it was demonstrated that on the surface, the octyl galactofuranoside crystallized orthorhombic with space group P2₁2₁2₁. The molecular packing calculated from X-ray data showed bilayer structures with interdigitated octyl chains. Finally, the mycobacteriostatic properties of Gly-plasticized PBAT/NaCAS films were evaluated from a modified Kirby-Bauer test.