Impact of Alkali Treatment on Prosopis juliflora Bark as Filler in Poly Lactic Acid for Flexible Packaging Films

ABSTRACT

The present study examined the effect of incorporation of alkali‐treated biowaste Prosopis juliflora Bark Powder (PJBP) into polylactic acid (PLA) as a renewable alternative to petroleum‐based polymers in packaging applications. Different alkali treatment times improved the compatibility of PJBP with PLA. Biofilms were prepared by solution casting and their surface, mechanical, thermal and degrading properties were evaluated. Fourier‐transform infrared spectroscopy confirmed the reduction of hemicellulose and lignin in alkali‐treated PJBP/PLA films. Agglomeration of filler and pits development were observed due to severe alkali treatment while prolonged alkali treatment increased surface roughness. In particular, the PLA/VHLATPJBP, the very high‐level alkali‐treated PJBP integrated PLA film, exhibited good thermal stability at 353°C. The treated high‐level composite film (PLA/HLATPJBP) showed an increase in tensile strength (38.9 MPa) due to the better interfacial adhesion. Also, alkali treatment led to a decrease in water absorption in comparison to the untreated PJBP‐incorporated PLA sheets (PLA/UTPJBP). The improved mechanical and barrier properties of the PLA/HLATPJBP biocomposite film make it promising for packaging applications although the alkali‐treated samples showed a slightly slower deterioration.