Effect of Bio‐Scavengers on the Curing Behavior and Bonding Properties of Melamine‐Formaldehyde Resins

Abstract

Summary: The effects of bio‐scavengers on the formaldehyde emission, bonding strength, curing behavior, and thermal decomposition properties of MF resins for engineered flooring and adhesion for wood were investigated. Four varieties of bio‐scavengers, tannin powder, wheat flour, rice husk flour, and charcoal, were added to MF resin at 5 wt.‐%. To determine formaldehyde emission and bonding strength, we manufactured engineered floorings. MF‐charcoal was most effective in reducing formaldehyde emission because of its porous nature, but its bonding strength was decreased. Tannin powder and wheat flour, which contain more hydroxyl groups, showed higher bonding strength and curing degree than pure MF resin did. Although the hydroxyl groups of the bio‐scavengers were effective in reducing formaldehyde emission and improve bonding strength and curing degree, rice husk flour and charcoal behaved like inorganic substances, thereby disturbing the adhesion between MF resin and wood and thus reducing the bonding strength. In thermogravimetric analysis, MF‐tannin showed the highest thermal stability in the low‐temperature range from 100 to 300 °C.Storage modulus (E′) of MF resin with various bio‐scavengers at a heating rate of 10 °C · min−1.magnified imageStorage modulus (E′) of MF resin with various bio‐scavengers at a heating rate of 10 °C · min−1.

The influence of scavengers on VOC emissions in particleboards made from pine and poplar

“…In the last decades, several studies using formaldehyde scavengers have been published (Eom et al 2006;Kim et al 2006;Kim 2009;Costa et al 2013a, b), as well as on resin synthesis optimization for low formaldehyde emission wood-based panels (Ferra et al 2010;Costa et al 2012;Paiva et al 2012), some of them with notable success, reaching formaldehyde emission near solid wood level and also zero emission. Some innovative works studied new formaldehyde-free adhesives, but their difficult application (Prasittisopin and Li 2010) and low reactivity (Despres et al 2010;Tang et al 2011) lead to high pressing times and lower productivity, having no acceptance in the industry.…”

Green Binders for Wood Adhesives

“…The formaldehyde emission was decreased with the addition of tannin [126]. The effect of addition of tannin in PF and MF resins was also studied, and the observed results were improved water resistance and decreased formaldehyde emission [127].…”

Wood production, wood technology, and biotechnological impacts

“…formaldehyde released naturally by the wood itself (Pizzi 1983. Addition of formaldehyde scavengers to the wood material in panel board production might help to reduce such formaldehyde emissions (Sellers et al 1991, Tohmura et al 2005, Kim et al 2006) -avoidance of formaldehyde as much as possible by replacing the type of glues is a most obvious strategy and another to establish techniques for production of binder-free boards. Strategies and further research projects in these areas are presented in Chapters 16 and 18 of this book.…”