A Study on the Effect of Chemical Composition on Properties of Lignosulfonate Prepared from Larch Tannin Extraction Residue

Chemical composition of larch bark residue after tannin extraction was analyzed and sulfonation reaction was proceeded on bark residue. Effects of sulfonation of bark chemical components on surface activity, dispersing property and fluidity of cement paste products were studied. Results showed that the main chemical compositions of bark residue after tannin extraction were phenolic acid and lignin, which were much higher than that of wood raw material. Hydrolysable tannin and condensed tannin also existed in bark residue. Lignosulfonate prepared from bark residue had better surface activity, dispersing property, the reason might be the existence of soluble tannin and phlobatannin, high fluidity of cement paste might come from the existence of soluble tannin and phenolic acids.