Chemical Modification of Plasticized Lignins Using Reactive Extrusion

Romain Milotskyi; László Szabó; Kenji Takahashi; Christophe Bliard

doi:10.3389/fchem.2019.00633

Chemical Modification of Plasticized Lignins Using Reactive Extrusion

Front Chem. 2019 Sep 18:7:633. doi: 10.3389/fchem.2019.00633. eCollection 2019.

Authors

Romain Milotskyi^{1

2}, László Szabó², Kenji Takahashi², Christophe Bliard¹

Affiliations

¹ Institut de Chimie Moléculaire de Reims, ICMR, CNRS UMR 7312, URCA, B18, UFR SEN, Reims, France.
² Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan.

Abstract

The reaction of esterification of plasticized Kraft lignin (KL) with succinic and maleic anhydrides using reactive extrusion (REX) was studied in detail. DMSO, glycol and glycerol were found to be efficient plasticizers for lignin. The chemical structure of these new lignin esters was determined using Solid-state ¹³C CP-MAS NMR and FT-IR analysis. ³¹P NMR analysis of phosphitylated lignins showed that the aliphatic OH groups of lignin had superior reactivity under the reactive extrusion reaction conditions. The formation of monoesters was confirmed by HSQC NMR spectroscopy. Molecular weight changes after extrusion process were studied using GPC/SEC chromatography. Thermal properties of these polymers were assessed by TGA analysis. The results were compared to lignin esters modified in classical batch conditions. These results show that REX can be used as a new fast, solvent free, and continuous process for lignin valorization.

Keywords: 31P NMR; DMSO; esterification; extrusion; kraft lignin; plasticizing.