Toughness Improvement of Epoxy Composites Using a Kind of Environment-Friendly Bio-Based Polyester Polyol

Epoxy resin (EP) is a thermosetting resin with prominent performances and wide applications. However, the inherent brittleness limits its development in the engineering materials area. A liquid bio-based polyester polyol (LLP) with flexible long chains was synthesized in this study by melt polycondensation of corn straw lignin. After being compounded with EP (LLP/EP), the mechanical property, micromorphology and thermal behavior of the composite were evaluated. The experimental result indicated that the fracture brittleness of EP composite was decreased by importing the LLP. The bending and impact strength were up to 113.67 MPa and 51.29 kJ/m(2) for 10%-LLP/EP, which were 5.25% and 27% higher than those of unmodified EP. The results of this work build new avenues for the efficient utilization of lignin and the development of low-cost, high-performance and well environmentally adaptable EP composite by renewable resources. [GRAPHICS] .

Automated summary

This study synthesized a liquid bio-based polyester polyol (LLP) with flexible long chains through melt polycondensation of corn straw lignin, and compounded it with epoxy resin (EP). The results showed that the brittleness of EP composite was reduced and the bending and impact strength were increased by incorporating LLP. This work opens up new avenues for the utilization of lignin and the development of low-cost, high-performance and environmentally adaptable EP composites using renewable resources.