Lignin-based epoxy and nano-cerium oxide boost carbon fiber composite strength by up to 95 percent

Researchers have developed a new interface design for carbon fiber composites that combines flexible lignin-based epoxy with rigid nano-cerium oxide particles. The approach improved interlaminar shear strength by 55 percent, flexural strength by 95 percent, and tensile strength by 67 percent compared to unmodified composites. The lignin component is a renewable alternative to petroleum-based modifiers, making the process more sustainable. The method works by creating a multi-level interface that improves stress transfer and energy dissipation. The rigid nano-cerium oxide particles provide mechanical interlocking and crack deflection, while the flexible lignin-based epoxy forms stable covalent bonds with both the carbon fibers and the resin matrix. This combination gives composites both high strength and toughness. For industries like wind energy, aerospace, and automotive that use carbon fiber composites, this could mean lighter, stronger parts with a lower environmental footprint. The processing route is relatively simple, which could help with scaling. The full study is published in Progress in Organic Coatings.