Preparation of Biocomposites using Sawdust and Lignosulfonate with a Culturе Liquid of Levan Producer Azotobacter vinelandii as a Bonding Agent

Abstract

The possibility of preparing molding-bioengineered materials, such as woodchip boards (WCB), from sawdust using technical lignosulfonate (LGS), a wood waste product, and a culture liquid (CL) of levan microbial polysaccharide producer by Azotobacter vinelandii D-08 is explored in this article. The parameters of the derived materials are comparable to those of traditional materials made from toxic phenol-formaldehyde resins. The various physical and mechanical characteristics of the materials depend on the quantity of the bonding agent used for the preparation. Adding a culture liquid increases the humidity resistance of the molding materials. Using electron microscopy and X-ray micro-tomography, it is clear that the structure of woodchip boards become more homogeneous without microcracks with the addition of CL. The strength of the best samples prepared was approximately 24 to 29 MPa with a density of 1170 to 1255 kg/m3 and a swell on wetting of 6.7%. During hot pressing, noticeable changes were observed by Fourier transform infrared spectroscopy (FTIR) at frequencies typical of LGS sulfonic-acid groups, levan fructose fragments, and skeletal vibrations of a syringal/guaiacyl core in lignin and of C-H groups of hemicelluloses. This indicates the involvement of these functional groups in the process of binding wood particles with hot pressing.

Keywords

• Lignosulfonate
• Levan producer
• Azotobacter vinelandii D-08
• Adhesion
• Molding materials
• Wood waste