Impact of PEO structure and formulation on the properties of a Lignin/PEO blend

Abstract

To improve the performance of lignin/PEO fibers as precursors of carbon fibers, blend formulations were designed with an epoxidized PEO and with carbon nanotubes. Model studies demonstrated that the epoxidized PEO could covalently link to lignin. With incorporation of epoxidized PEO, the precursor fibers exhibited enhanced degree of crystallinity of 70 % (52 % without epoxidized PEO) and a doubling of their young modulus (from 200 to 450 MPa) and tensile strength (from 6 to 12 MPa). In contrast, the addition of carbon nanotubes did not impact the morphology nor the mechanical performance of the resulting fibers. It is argued that with its ability to couple lignin to the PEO matrix, epoxidized PEO plays the role of a stress transfer agent between the rigid lignin regions and the flexible PEO regions, thereby improving the blend performance.