An Investigation of Complexes of Lignin Found in Plant Raw Materials as a Natural Binder in Obtaining Plastic in Closed Molds

It has been suggested that lignin of wood and plant origin is directly involved in the formation of plastics without the addition of binders due to the formation of a net structure. The performed studies using DSC showed the presence of two peaks under the influence of temperature and water—hydrolytic destruction of the lignin–carbohydrate complex and further polycondensation of its “fragments” into a cross-linked polymer with the formation of plastic. The use of catalysts such as polyoxometalates (by the example of manganese-containing sodium vanadomolybdophosphate) makes it possible to carry out preliminary partial destruction of lignin and obtain plastics under “softer” conditions. In this case, it is necessary to take into account the different chemical structure and lignin content in the initial molding material, which determines not only the conditions for obtaining, but also the properties of the resulting material.