Relations between structure and equilibrium mechanical properties of polyurethane networks based on poly(butadiene) diol, 4,4'-diphenylmethane diisocyanate (MDI) and poly(oxypropylene) triol (POPT) prepared at various initial ratios of reactive groups were studied. An inhomogeneous structure of the networks was revealed by small-angle X-ray scattering. The microdomains consist of POPT molecules crosslinked with MDI and they have a diameter of about 4-5 nm. The characteristic distance of microdomains is about 9 nm. The poor mutual miscibility of the reaction components and the existence of hydroxyl group association in the reaction mixture are the probable reasons for microdomain formation. The strain dependence of the equilibrium elastic force obeyed the Mooney-Rivlin equation. The experimental moduli of dry and equilibrium swollen samples were higher than those calculated for the affine limit of the Flory junction fluctuation model on the assumption of a homogeneous network formation.
Посилання на статтю:
Structure and elasticity of polyurethane networks based on poly(butadiene) diol, 4,4'-diphenylmethane diisocyanate and poly(oxypropylene) triol / Ivan Krakovsky, Josef Plestil, Michal Ilavsky and Karel Dusek // Polymer. – 1993. – Vol 34. – P. 3437-3445.