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Polysaccharides as adhesives for wood particleboards
- Tijana Todorovic
- Co-author(s): Deniz Demircan, Jesper Ekström, Lars Hjelm, Eva Malmström and Linda Fogelström
- Today, most of adhesives used in the particleboard industry are fossil-based and contain hazardous component such as formaldehyde. By using biobased adhesives that do not contain hazardous components, wood industry could transit to a more sustainable and benign production. In our work, we have evaluated polysaccharides as components in fully biobased adhesives for wood particleboards, and investigated the effect of the processing parameters on particleboard properties. Particleboards prepared with adhesives containing only wood hemicelluloses did not have a sufficient strength. However, by adding only 10 % chitosan, the internal bond strength of particleboards fulfilled standard requirements for boards commonly used for furniture in dry conditions (P2). The order of the adhesive-components’ addition affected the internal bond strength; by adding chitosan first, it could form films on the wood particles and prevent over-penetration of hemicelluloses.Since the mat moisture content was higher than what is usually used in the particleboard industry, we have investigated the effect of the mat moisture content on particleboards prepared with hemicelluloses. In this study, we have used galactomannan from the carob tree as a hemicellulose model. Results showed that effective hydration of the polymer chains is necessary for achieving satisfactory interactions with wood and a sufficient particleboard strength. The internal bond strength of particleboards fulfilled standard requirements for P2 boards when the mat moisture content was above 35 % and the pressing time was long enough to allow for water and vapors to be removed before releasing the pressure.
