Effect of lignin on mechanical,biodegradability,morphology,and thermal properties of polypropylene/polylactic acid/lignin biocomposite

Abstract

The effects of lignin on mechanical, biodegradability, morphology, and thermal properties of PP/PLA/lignin were investigated. PP/PLA/lignin film were manufactured by adding PP, PLA, lignin and compatibilizer into rheomix at 200°C, at 70 rev min⁻¹ for 30 minthen pressed using Hydraulic Hot Press at 200°C–210°C, at 6 bar for 20 min. The functional groups of PP/PLA/lignin were analyzed using FTIR. The surface morphology, mechanical properties and thermal stability was measured by SEM, tensile strenght and TGA respectively. TThe FTIR intensity of vibration peak of –CH₃ cm^-1 from PP/lignin and PP/PLA/lignin at 997–993, 1458–1451 and 2966–2904 cm^-1 was lower than neat PP. The addition of lignin into PP/lignin, PLA/lignin and PP/PLA/lignin can reduce tensile strength and elongation at break. The thermal stability PP/PLA/lignin was lower than the PP/lignin but higher compared to PP/PLA biocomposites. The biodegradability of PP/PLA/lignin biocomposites was two times higher than that of PP/lignin.