Synergistic effect of lignin and ethylene glycol crosslinked epoxy resin on enhancing thermal, mechanical and shape memory performance.

Lignosulfonate (LS) was successfully introduced into the epoxy resin matrix with the aid of ethylene glycol (EG) dissolution. Both the rigid LS and soft EG segments were linked into the cross-linked network structure of epoxy resin via esterification of hydroxyl groups in LS and EG molecules with anhydride. The ultimate properties of cured samples were adjusted effectively by changing the proportion of LS and EG components.

Intumescent Flame Retardant Mechanism of Lignosulfonate as a Char Forming Agent in Rigid Polyurethane Foam.

Intumescent flame retardants (IFR) have been widely used to improve flame retardancy of rigid polyurethane (RPU) foams and the most commonly used char forming agent is pentaerythritol (PER). Lignosulfonate (LS) is a natural macromolecule with substantial aromatic structures and abundant hydroxyl groups, and carbon content higher than PER. The flame retardancy and its mechanism of LS as char forming agent instead of PER in IFR formulation were investigated by scanning electron microscopy, thermogravimetric analysis, limiting oxygen index testing and cone calorimeter test.

Kinetics of partially depolymerized lignin as co-curing agent for epoxy resin.

Lignin, which is crosslinked by ether and carbon‑carbon linkages, is a highly branched polymer consisting of phenyl propane units. And owing to the abundant phenolic hydroxyl groups and its structural heterogeneous characteristics, lignosulfonate, considered as a renewable aromatic macropolymer, can be used as co-curing agent in EP thermoset systems. In this study, kinetics of lignosulfonate (LS) and partially depolymerized lignosulfonate (DLS) as co-curing agents for applications to EP thermoset were discussed with the differential scanning calorimetry (DSC) measurement.

Covalent linkages between cellulose and lignin in cell walls of coniferous and nonconiferous woods.

Covalent linkages between wall polysaccharides and lignin, especially linkage between cellulose and lignin were discussed by carboxymethylation technique of whole cell walls of coniferous and nonconiferous woods. Hydroxyl groups of plant cell walls polysaccharides were highly substituted, but not those of lignin by carboxymethyl groups under the used conditions, and separated into water-soluble and insoluble fractions by water extraction. Carboxymethylated wall polysaccharides linked covalently with lignin were distributed into the water-insoluble fractions.

Changes in lignin content of leaf litters during mulching.

Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W.