Synthesis route of LPEGs. a The epoxidation reaction of alkaline lignin. b Introduction of PEGs into lignin through the reaction of epoxy lignin with PEGs (ECH epichlorohydrin, TBAB tetrabutyl ammonium bromide, Z the intermediate of the ring-opened reaction of epichlorohydrin with lignin, LERM lignin-based epoxy resin monomer, PEGs PEG600 or PEG1000, KPS potassium persulfate, LPEGs water-soluble lignin derivatives)