Preparation of bio-composite from wood sawdust and gypsum

Abstract

Bio-composite which is made of wood sawdust (SW) with novel modification and gypsum is presented in this paper. Attenuated total reflectance-fourier transform infrared (ATR-FTIR) characterizations reveal that the main compositions of sawdust water extractives are tannins, acetic acid, hemicellulose, and lignin. Positive effect of sawdust water extractives on gypsum was achieved by the addition of antifoam agent. Mechanical testing shows that the mechanism of sawdust induced reduction of gypsum performance may be attributed to the water absorption of sawdust. Subtraction and matching analysis with OMNIC software indicates that water-based epoxy (WEP) could be coated on the surface of sawdust by using spray coating, which resulted in a reduction of the water absorption of sawdust up to 25.6% and water content inside gypsum/sawdust composite up to 35.8%. Mechanical testing of gypsum/sawdust composite shows that the light weight composite with promising mechanical performance could be obtained by the WEP treatment: for 20% sawdust addition, the flexural strength and compressive strength of composite are 4.59MPa and 13.25MPa, respectively; for 30% sawdust addition, the flexural strength and compressive strength of composite are 3.36MPa and 8.73MPa, respectively.