A method for increasing the negative charge of a lignocellulosic material and a modified lignocellulosic material with an increased charge density

摘要

A process for production of a lignocellulosic material modified by conjugation thereto of a phenolic substance comprising a substituent which, in the conjugated form of the phenolic substance, is, or may become, negatively or positively charged, respectively, comprises: reacting a lignocellulosic fibre material and the phenolic substance with an oxidizing agent in the presence of an enzyme capable of catalyzing the oxidation of phenolic groups by the oxidizing agent; and reacting together the products of the reactions; with the proviso that the phenolic substance is not a phenolic polysaccharide. A strengthened lignocellulose-based product (e.g. a paper product) may be prepared by a procedure wherein a product produced in accordance with the latter process is treated with a strengthening agent having an ionic charge of sign opposite to that which is conferred on the modified lignocellulosic material by the charge-conferring substituent.