Oxygen-organosolv lignins, isolated from spent liquors after delignifi
cation of wood in different acidic organic solvent-water media, were u
sed as unmodified macromonomers in conjunction with an oligoethyleneox
ide di-isocyanate. This led to crosslinked elastomeric polyurethanes w
hich were thoroughly characterized. It was found that the nature of th
e organic solvent used for the organosolv pulping had an influence on
the reactivity of the isolated lignins towards the di-isocyanate becau
se of the variation in the amount of alcoholic groups caused by reacti
ons with solvent molecules during the delignification. (C) 1998 Elsevi
er Science Ltd. All rights reserved.