Utilization of agricultural rests: Straw-based composite panels made from enzymatic modified wheat and rapeseed straw

Abstract

The paper deals with the possibility of using post-harvest crop residues, namely winter wheat straw and winter rapeseed straw for the purpose of producing particleboards. In order to increase particle surface energy, particles were treated with enzymes prior to application of the adhesive; xylanases, pectinase, and a combination of both. The effect of the enzymatic treatment on the properties of the treated particles was monitored and, after the production of the boards, the influence of particle treatment on the mechanical and physical properties of the composites was also monitored. The effect of enzymatic modification on the properties of wheat and rapeseed particles was observed. The enzymes used influenced the particle surface morphology, their surface energy and equilibrium moisture content. Only the combination of pectinase and xylanase (Texazym SER 7) increased the surface energy of wheat surface from 26 mN/m (untreated) to 30 mN/m. The greatest erosion of the surface was achieved by the combination of xylanases and pectinases. After enzymatic treatment both wheat and rapeseed straw exhibited higher equilibrium moisture content. The increase of moisture of wheat straw was from 11.9 %–13.2 % and of rapeseed straw from 12.4 %–13.44 %. Although the selected enzymes had an effect on the properties of the particles, the effect of the enzymatic treatment on the equilibrium moisture, the internal bond strength and the bending characteristics of the produced particleboards were not observed. Produced boards reached low mechanical properties, internal bond strength reached values form to 61–99 mN/mm2.