Location: Commodity Utilization ResearchTitle: Wood adhesives containing proteins and carbohydrates
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/26/2016
Publication Date: 2/14/2017
Citation: Cheng, H.N., He, Z. 2017. Wood adhesives containing proteins and carbohydrates. In: He, Z., editor. Bio-based Wood Adhesives: Preparation, Characterization, and Testing. Boca Raton, Florida: CRC Press. p. 140-155.
Interpretive Summary: Formaldehyde-based resins are among the most commonly used ingredients in wood adhesive formulations. Because of environmental concerns with formaldehyde, there has been renewed interest in recent years in using biopolymers, particularly proteins and carbohydrates, as alternative ingredients. This article serves as a review of the recent literature on the use of proteins and carbohydrates in wood adhesives, including the benefits of these systems, the problems encountered, and some of the solutions. This information will allow wood adhesive formulators, manufacturers, and consumers to evaluate the progress made thus far on eco-friendly adhesive ingredients and to consider adopting some of these materials as substitutes for the conventional petroleum-based adhesive ingredients.
Technical Abstract: In recent years there has been resurgent interest in using biopolymers as sustainable and environmentally friendly ingredients in wood adhesive formulations. Among them, proteins and carbohydrates are the most commonly used. In this chapter, an overview is given of protein-based and carbohydrate-based wood adhesives. Included in the coverage are recent wood adhesives involving proteins, carbohydrates, glycoproteins, and protein/carbohydrate blends. A lot of interesting developments have been reported, particularly entailing modification reactions, use of additives, and blending. For example, soy protein is an often-used ingredient for wood adhesives, and commercial wood adhesive products involving soy protein are available. It has been found that cottonseed protein added to soy protein can improve both its dry strength and its water resistance. In addition, cottonseed- and soy-protein based adhesives have been formulated with xylan, starch, or celluloses to determine the influence of polysaccharide fillers on protein-based adhesive properties. In some cases, adhesive strength is retained even when the cottonseed or soy protein is mixed with up to 75% polysaccharide.