Upcycling of Kraft lignin for Lignin-Polystyrene Copolymer via Etherification

Authors: Chaemin Lee, Chang Geun Yoo

SUNY Campus: SUNY ESF

Presentation Type: Poster

Location: UU 111

Presentation #: 74

Timeslot: Session A 9:00-10:00 AM

Abstract: Lignin is a renewable biopolymer with a cross-linked, amorphous structure containing various functional groups such as hydroxyl, methoxy, carbonyl and carboxylic groups. Kraft lignin, a by-product of the pulp and paper industry, is produced in large quantities through the kraft process. It has been simply combusted as an energy source in the pulping process; however, it has a great potential to replace several petroleum-based materials due to its aromatic nature. While its availability and sustainability make it an attractive raw material, its industrial applications still remain challenging because of its heterogeneity and low processibility with petroleum-based polymer. Polystyrene is a widely used hydrophobic and thermoplastic polymer used in thermal insulation and food packaging. It is typically synthesized via free-radical polymerization of fossil-based styrene. However, original kraft lignin has low miscibility with nonpolar polymers, so its direct integration into polymer matrices is limited. Therefore, in this study, lignin etherification was conducted to graft lignin molecule with styrene, synthesized the lignin contents up to 10%. The modified kraft lignin was characterized using two-dimensional heteronuclear single quantum coherence (2D HSQC), and phosphorus (31P) NMR. The thermal and morphological properties of the lignin-polystyrene copolymers were analyzed using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM).