New polyurethanes with mesogenic units in the main chain due to the use of a liquid crystalline chain extender were synthesized
from 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI)using diisocyanates of different trans, trans isomer content, a low molecular diol4,4'-bis(6-hydroxyhexoxy)biphenyl (BHHBP) and a high molecular poly(hexyleneadipate)diol
(PHA). The growth of trans, trans isomer content in HMDI used to syntheses of PU induces monotonic growth of melting point, rectilinear growth of crystallization
temperatures and the growth of crystallization enthalpy, both for hard segment polyurethanes and block polyurethanes. The
increase of trans, trans isomer content in HMDI increases also glass transition temperatures and dynamic storage modulus of the polyurethanes.