Eco-friendly films prepared from plantain flour/PCL blends under reactive extrusion conditions using zirconium...

Plantain flour (Musa ssp., group AAB, sub-group clone Harton)/poly(ε-caprolactone) (PCL) blends, containing glycerol as a plasticizer, were prepared by reactive extrusion (REx) in a twin-screw extruder using zirconium octanoate (Zr(Oct)₄) as a catalyst, followed by thermo-compression molding for film development. The films were then characterized in terms of their: infrared (FTIR) spectra, water solubility, thermogravimetric (TGA) curves, differential scanning calorimetry (DSC) thermograms, and X-ray diffraction (XDR) diffractograms, as well as their microstructural, mechanical and antimicrobial properties in order to (1) compare the effects of PCLs with two different molecular weights (M_w) on the characteristics of the plantain flour/PCL blends, and (2) determine whether using Zr(Oct)₄ in the production of active composite polymer materials improves their properties. The plantain flour/PCL blends were all developed successfully. The higher M_w PCL gave more hydrophobic and thermally stable films with improved mechanical properties. The addition of the Zr(Oct)₄ catalyst to the plantain flour/PCL blends also resulted in films with similar characteristics to those described above, due to the cross-linking of the polymers. In addition, the films containing the catalyst showed antimicrobial activity against Escherichia coli O157:H7 and Staphylococcus aureus indicating a dual effect of Zr(Oct)₄, and making it an attractive alternative for the development of active films.