Effects of nanotechnology on fluid flow in agricultural and wood-based composite materials

Abstract

Wood is a natural renewable material with continuous porous structure. Density in each wood species significantly depends on its porosity. The continuous porosity in wood provides easy transfer of different fluids through it. Wood is mainly composed of three polymers, including cellulose, hemicellulose, and lignin. The hydroxyl groups (-OH) in cellulose and hemicellulose are mostly free, providing opportunity for water molecules to easily make bonds with them. This is the root cause for shrinkage and swelling phenomena in wood and wood-composite materials. In wood composites, constant and repeated shrinkage and swelling result in breakdown of the resin bonds in the composite matrix, eventually weakening the whole structure. Moreover, water molecules interact with resin polymer, significantly weakening its strength. Easy transfer of water vapor and liquid through composite matrix speeds up this process. It is therefore necessary to monitor, and if possible to decrease, flow of water vapor and droplets into the wood-composite matrix, increasing its service life. A brief overview of the research project carried out on the utilization of nanomaterials in the wood-composite manufacturing industry proved numerous potential applications of nanotechnology in this industry. The use of metal and mineral nanomaterials with high thermal conductivity coefficient helps to improve thermal conductivity and better cure of the resin, resulting in a significant decrease in gas and liquid permeability. Improved thermal conductivity also helped to decrease press time to a considerable extent, lowering production costs, as well as accelerating the production rate. The water-repellent property of some nanoparticles (nanozycosil) can also hinder penetration of water and vapor into wood-composite matrix; ultimately, the service life of the parts used in the furniture or structure would significantly increase.