Study on wood chips modification and its application in wood-cement composites

Abstract

Wood-cement composites have the advantages of high flexural strength, toughness, and impact resistance. However, the components such as hemicellulose and lignin in the wood chips can inhibit cement hydration, and thus the interface bonding between wood chips and cement matrix is poor. In order to address these issues, alkali cooking (mass concentration is 2–8%) and silane coupling agent (mass concentration is 1–5%) were used in this study to modify wood chips, and the resulting compressive and flexural strengths of wood-cement composites prepared from different kinds of modified wood chips were evaluated. Further, the XRD, SEM, and FT -IR tests were carried out to characterize the modified wood chips and explore the mechanism of modified wood chips incorporated composites. The results showed that the alkali cooking agent could effectively remove amorphous components, such as hemicellulose and lignin, from wood chips, improve crystallinity and relative cellulose content, and increase the surface roughness of wood chips. The silane coupling agent could chemically bond with wood chips to improve the interfacial properties between wood chips and cement matrix. The flexural strength of the composites prepared with wood chips treated with 3% silane coupling agent and 4% alkali cooking agent was increased, which was 11.9% higher than that of the composites prepared from wood chips treated only with 4% alkali cooking agent, while it was 27.1% and 31.6% higher than the composites prepared with untreated wood chips and mortar without wood chips, respectively. Alkali cooking modification and silane coupling agent treatment of wood chips can effectively improve the mechanical properties of composite materials.

Keywords

• Wood chips
• Surface treatment
• Cement-based composites
• Mechanical properties