Mechanical Properties of Solvolysis Lignin-derived Polyurethanes

In order to study the tensile properties of solvolysis lignin polyurethanes, polyurethane (PU) films were prepared from the solvolysis lignin (SL) - polyethylene glycol (PEG) - diphenylmethane diisocyanate (MDl) system, and in addition to this further PU films were also prepared from the SL-MDl system. In the SL-PEG-MDl system, the SL content, the molecular weight of PEG and the NCO: OH ratio were varied in order to control the physical properties. The tensile stress and Young`s modulus of the PUS of the SL-PEG-MDl type increased with increasing SL content and NCO: OH ratio. The tensile properties of the PUS from the SL-MDl system showed no NCO:OH ratio dependency; i.e. the mechanical properties of PUS are not influenced by the change in crosslinking. It is possible to control the tensile properties of PUS of the SL-PEG-MDl type by changing the content of PEG and SL at a constant NCO: OH ratio.