Abstract: In the present research, coniferin-[α-¹³C]is co-polymerized with fibers of Bio-CMP of wheat straw and pectin catalyzed by laccase. A wet method was used for the formation of high-strength fiberboards. The results indicated that the thickness expansion rate of water absorbing (TS), the internal bond (IB), the modulus of rupture (MOR), and the modulus of elasticity (MOE) reached 16.7 %, 0.6 MPa, 25.1 MPa and 2 500 MPa,respectively. As a result, all mechanical properties of the medium-density fiberboard (MDF) can meet or exceed the standards of GB/T 11718-2009. According to CP/MAS ¹³C NMR, lignin-carbohydrate complexes(LCC) were formed between lignin and polysaccharide. Pectin and xylan in fibers were crosslinked with high through benzyl ether linkages and ester bonds, and β-aryl ether linkages were formed between lignin. Furthermore, pectin and coniferin were easy to form pectin-DHP in the presence of laccase. These complexes and linkages result in a further improvement of mechanical properties of MDF and reduction of TS.

Key words: coniferin-[α-¹³C], laccase, fiberboard, mechanical properties, crosslinking