Biobased fire protection of wood panel for exterior conditions by using phosphorylated lignin from wheat straw

Sustainable wood materials stable to fire are of outmost interest in a growing bioeconomy especially as visible wood in exterior panels and surfaces in tall wooden buildings.

Fixation of commonly used fire retardants in wood is mostly based of non-renewable systems and synthetic resins that needs to be replaced with biobased solutions.Lignin is the second most common organic material, has a huge potenial and when isolated from wheat has features such as low extent of non cleavable cross-links and relatively high content of para-hydroxyphenyl propane units well suited for modification of agents with fire retardant properties and further fixation into wood.

Phosphorylation but also sulphamic acid/urea as well as boron nitride is of interest to achieve a high fire retardant product.

The phosphorylated lignin is isolated via acetone extraction and its lowered molecular weight and higher solubility will be of benefit for reaching deep into wood from sapwood of Scots pine when impregnated. Use of lignin model compounds and other lignins are of a good help for developing such methods.

Conditions and reagents for fixation of the product will be delevoped which will be a guide when applied to solid wood. Process conditions, product and intermediate properties will be studied using by mass spectrometry, viscosimetry etc.

During the development of the materials we will perform tests of resistance to fire, stability against weathering and biodegradation.