Thermal stability, hydrophobicity and antioxidant potential of ultrafine poly (lactic acid)/rice husk lignin fibers

The objective of this study was to produce an antioxidant and hydrophobic membrane formed by ultrafine fibers using poly (lactic acid) (PLA) 8% and different concentrations of lignin from rice husk [(0.5%, 1.5% or 2.5% (w v−1)] dissolved in chloroform/acetone (3:1) solvent, by electrospinning technique. The ultrafine fibers were characterized by morphology, diameter distribution, functional groups, thermal stability, hydrophobicity and antioxidant capacity. The morphology showed ultrafine fibers with average diameters between 314 and 587 nm and the thermogravimetric analysis (TGA) indicated thermally stable fibers, with a peak of degradation around 360 oC. The wettability analysis performed with distilled water showed that all treatments had a hydrophobic surface, with contact angles between 100.3° and 101.8°. The ultrafine fibers containing 2.5% lignin exhibited the highest antioxidant activity, with inhibition of around 70% for both radicals, DDPH and ABTS. Thus, the ultrafine fibers membrane proved promising for application as food packaging with thermal stability, hydrophobicity surface and antioxidant activity.