Wood modification with DMDHEU (1.3-dimethylol-4.5-dihydroxyethyleneurea) – State of the art, recent research activities and future perspectives

ABSTRACT

This study reviews previous and recent findings on wood modification via wood-polymer-integration with cyclic N-methylol compounds and puts them into a common context. Originally used for the finishing of cellulose-based textiles, the treatment of wood with low-molecular-weight N-methylol compounds of ethylene urea has been studied in the late 1950s for the first time. An improved dimensional stability was found and confirmed in the 1990s coming along with improved durability. Since such reagents can penetrate in wood cell walls and react with hydroxyl groups of cell wall polymers, a good fixation and permanent enhancement of some wood properties are achieved. Since 1990 this promising approach was followed by intensive fundamental and applied research, focused on treatment of Scots pine (Pinus sylvestris L.) and European beech wood (Fagus sylvatica L.) with 1.3-dimethylol-4.5-dihydroxyethyleneurea. In the early 2000s, a modification process was developed up to pilot scale, optimized for Scots pine and close to the market launch (Belmadur^®Technology, BASF). However, market penetration was not reached yet. Therefore, investigations were resumed in 2016. To forward this modification technique, recent trials focus on formaldehyde-reduced and formaldehyde-free cross-linking agents from textile and paper applications. Different permeable fast-growing wood species are subject of further research.

KEYWORDS:

• Chemical wood modification
• cross-linking
• dimensional stability
• durability
• hardness
• N-methylol

Disclosure statement

No potential conflict of interest was reported by the authors.