Novel green and cost-effective preparation of acetylated lignin at high temperature without further separation

Abstract

In order to realize the green and low-cost industrial production of acetylated lignin, this work proposes the heterogeneous reaction to acetylated lignin (ACAL) without catalysts and solvents at high temperature. The influence of reaction temperature and reaction time were investigated by IR, UV–vis, thermogravimetric analysis and water contact angle. Results showed that the optimum technological conditions were about 150 °C and 6 h. The degree of acetylation and the amount of residual phenolic hydroxyl groups of ACAL was 2.49 and 34.2%, respectively. Compared with conventional acetylated lignin, the ACAL had similar hydrophobicity with a water contact angle of 62.0°. The DTG peak of ACAL at about 200 °C reduced to 0.07 than the traditional acetylated lignin. The tensile strength and elongation of poly-lactic acid with 5 wt% ACAL increased to 64.03 MPa and 10.80%, respectively. ACAL revealed a great potential for mass production and applications owing to the eco-friendly and cost-effective modified method.

Keywords

• lignin
• acetylation
• biomaterials
• eco-friendly