Researchers at the chemical laboratory of the University of Helsinki are researchong ion fluids, which could be used to glue wooden bricks together. The liquid is the same, which is used in developing a method to manufacture textile fiber from wood.
Ion fluids have been researched from the late 19th century. Their use as wood glue is based on that they dissolve lignin and cellulose. This is a way for the fibre molecules to rearrange themselves.
In practice, to glue two wooden bricks together by ion fluid, you first paint the fluid onto the bricks, press them together and put them in an oven. With the right pressure and temperature wood material transforms back to its original form, ion fluid is separated from the bricks and it can be recovered.
When the bricks are taken out of the oven, they are firmly attached to each other. Ion fluid has dissolved cellulose and lignin from the surface of the bricks and when the solvent has dissipated, the wooden parts have attached to each other.
’In microscope photos the cross-section of the joint bricks looks the same as an annual ring,’ says professor Ilkka Kilpeläinen from the university.