Flat biofilms extrusion of poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) grafted with glycidyl methacrylate blends: Toward ecological packaging for sustainability

Abstract Blends of poly(lactic acid) (PLA)/poly(butylene adipate‐ co ‐terephthalate) grafted with glycidyl methacrylate (PBAT‐ g ‐GMA) were developed to produce flat and flexible biofilms through extrusion. The PLA/PBAT‐ g ‐GMA (90%/10%, 80%/20%, 70%/30%, and 60%/40% by mass) blends were processed in the internal mixer, injection molded, and manufactured into flat films. The optimal composition to produce flexible biofilms was PLA/PBAT‐ g ‐GMA (60/40%), as it demonstrated a decrease in elastic modulus of 53.2% and a significant gain in elongation at a break of 4923% about pure PLA. The incorporation of 40% PBAT‐ g ‐GMA in PLA increased the torque ( Z ) by 208%, while the melt flow index (MFI) decreased by 51.57%, compared to PLA. Additionally, the degradation rate ( R z ) and molar mass loss ( R m ) during processing were minimized, indicating that 40% PBAT‐ g ‐GMA enhanced stability of the PLA matrix. Fourier transform infrared spectroscopy indicated interactions between the GMA of PBAT‐ g ‐GMA and PLA, justifying the increase in viscosity and elongation at break. The PLA/PBAT‐ g ‐GMA (60/40%) composition showed a transmittance in the range of 20%–48% (400–800 nm) and an oxygen gas permeability of 1.56 × 10 −5 cm 3 STP/cm −2 h bar, indicating its potential for applications in packaging with optical barrier properties. Scanning electron microscopy (SEM) revealed ligaments in the interfacial region between PLA and PBAT‐ g ‐GMA, confirming the good performance in elongation at break. The results presented are essential for the plastics processing sector, aiming to develop eco‐friendly packaging.