Durable composites by vulcanization of oleyl-esterified lignin

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomass Utilization

Background:

• Lignocellulosic biomass is a crucial resource, but lignin utilization remains a challenge.
• Existing methods for lignin-sulfur composites are limited by phase separation and low lignin content (≤5 wt%).

Purpose of the Study:

• To develop a protocol for increasing lignin hydrophobicity for enhanced incorporation into sulfur-rich materials.
• To create high-strength esterified lignin-sulfur (ELS) composites with significantly higher lignin content.

Main Methods:

• Esterification of lignin with oleic acid to improve hydrophobicity.
• Reaction of esterified lignin with sulfur at two different temperatures (180 °C and 230 °C).
• Mechanistic analysis and microstructural characterization of the resulting composites.

Main Results:

• Successfully prepared ELS composites with up to 20 wt% lignin.
• Identified distinct bond formations (S-C vs. C-S) at different reaction temperatures.
• Achieved compressive strength values exceeding 20 MPa, surpassing ordinary Portland cements.

Conclusions:

• The developed protocol effectively increases lignin utilization in sulfur-based composites.
• These durable ELS composites offer a sustainable alternative to conventional Portland cements.