Wood adhesives are important in many large-scale applications such as load-bearing constructions, flooring, furniture, windows, and doors, and are produced in large amounts every year. In 2015, the wood adhesives market size was estimated to nearly 2 million tons. Historically, wood adhesives were prepared from various natural polymers such as starch and proteins from blood or milk. However, the natural polymers were in the 1960s’ replaced with fossil-derived polymers due to their superior properties regarding bonding performance, easy handling and favorable cost development. Today’s fossil-based wood adhesives perform satisfactorily, but the fossil resource is limited and non-renewable. Many adhesives also contain formaldehyde, which is a hazardous compound that most likely will be banned from many applications in the near future. A rapidly growing environmental awareness, combined with the increasingly sharper formaldehyde regulations, is forcing the industry to find new environment-friendly and less fossil-dependent adhesives. In this study, we suggest hemicelluloses as the main component in wood adhesives, and we have prepared wood adhesives with hemicellulose from different sources: xylan from beech, hemicellulose-rich liquids obtained from hydrolysis of hardwood, and ultrafiltrated softwood hemicellulose recovered from the process water of a thermomechanical pulp mill. Hemicellulose itself does not exhibit sufficient bonding performance but in combination with poly(vinyl amine) both superior bond strength and water resistance were obtained. As a further improvement, it was shown that chitosan can be used as a biobased amine-containing alternative to poly(vinyl amine). Hemicelluloses in combination with chitosan exhibit exceptionally good bonding performance, especially regarding water resistance, and is superior to a commercial poly(vinyl acetate) adhesive.

A fully green wood adhesive based on hemicelluloses derived from pulp processes

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.