Application of polyvinyl alcohol (PVA) as a toughening agent in wood furfurylation

In order to explore the application of furfurylated wood as engineering material, polyvinyl alcohol (PVA) was proposed as a toughening agent to incorporate with furfuryl alcohol (FA) to form FA/PVA precursor and impregnate wood in a one-step method. After in situ polymerization upon heating, a hydrophobic network composed of polyfurfuryl alcohol (PFA) and PVA was formed within the wood scaffold. The impact toughness, as well as some water-related properties of modified wood including the contact angle, water absorption, moisture adsorption, and dimensional stability were investigated in this study. The results showed that the impact toughness of wood significantly decreased after furfurylation. The incorporation of PVA could alleviate the reduction, and this effect was more obvious for highly furfurylated wood. PVA could penetrate and bulk the wood cell wall to a certain degree, but increased concentration of PVA may negatively influence the penetration of FA in wood cell wall. PVA showed only slight influence on water-related properties of FA modified wood, and it depended on both concentrations of PVA and FA. All results indicate that incorporation of PVA in FA system is a promising approach to enhance the toughness of FA modified wood.