Strategies for compatibilisation of extracted lignin properties with commercial applications: general discussion

Joseph S. M. Samec opened the discussion of the paper by Mojgan Nejad: The use of epichlorohydrin (ECH) has been questioned; what is your take on the use of ECH? Mojgan Nejad responded: I totally agree and, to mitigate this challenge, we (1) used bio-based epichlorohydrin that is made of glycerol rather than toxic allylchloride, (2) used another bio-based co-solvent (ethyl lactate) to reduce the amount of ECH, and (3) analyzed the epoxidized lignin to ensure there is negligible residual ECH there (chloride content). Veronica Calado asked: Have you measured the mechanical properties and curing temperature? And which value is elevated? How about the viscosity? Mojgan Nejad answered: Yes, we have measured the mechanical properties of our lignin-based epoxy resins (with 40% ethyl lactate) using DMA, determined the curing temperature with DSC, and the viscosity with a rheometer. Compared to Epon, the epoxidized lignin had comparable performance to Epon resin when mixed with 40% ethyl lactate (solvent), similar to lignin–epoxy.