Lignin carbonates as crosslinkers for bio-based adhesives

Lead Institute HF Institute of Wood Research

[Translate to English:]

Multi-cyclic carbonates as crosslinker for biobased and formaldehyde-free adhesives

Adhesives are of central importance for industrial product manufacturing. However, conventional adhesives are usually based on petrochemicals and are thus not sustainable. The Thünen-Institute of wood research is investigating novel alternative adhesives made from bio-based resources.

Background and Objective

In the earlier project CycloCarb (FKZ 22027014, duration: 01.02.2016 - 15.09.2019), it was shown that pre-polymers can be obtained by the reaction of renewable (bio)polymers such as lignin with vegetable oil-based multi-cyclic carbonate compounds. These pre-polymers are pre-crosslinked viscous products with which wood can be effectively glued in the next step. Based on this, the aim is to (further) develop effective bio-based and non-toxic adhesives up to pilot plant scale.

Approach

First, multi-cyclic (vegetable oil-based) carbonates are prepared and lignins are selected. The obtained materials are characterized physicochemically. The substances are crosslinked to form pre-polymers by varying parameters such as temperature, reaction time and mixing ratios. Adhesive tests for tensile strength, shear strength and water stability are carried out with these products, with the possible addition of further substances. The results are compared with those of conventional adhesive systems.