The dehydrogenation polymer(DHP) and the DHP-carbohydrate complexes are prepared through the co-polymerization of the unbleached kraft pulp of low kappa number from hardwood and coniferin or coniferin/pectin in the presence of the lignin peroxidase. The ¹³C-NMR determination shows that the main substructures of the obtained DHP are β-O-4, α-O-4, β-β, β-5 and β-1 structures. Furthermore, it is also found that the DHP is linked with the pectin and the fibers of the kraft pulp by typical LCC linkages, i.e. the benzyl ether bonds, the ester bonds, and a small amount of ketal bonds. As a result, the paper strength is increased significantly after the rebuilding of the CML structure of the fibers. The dry and wet tensile strengths of the paper web are increased by 37.5% and 166.3% after treatment with the coniferin and the pectin. It is demonstrated that the lignin precursor can be co-polymerized with the pectin and the polysaccharides in the pulp fiber efficiently, to obtain the rebuilt CML, which binds the pulp fibers and therefore enhances the paper strength.

compound middle lamella  /  coniferin  /  DHP-carbohydrate complexes