Structure and viscoelastic behaviour of polyurethane networks from triisocyanate and polyols with different structures

Abstract

The dynamic mechanical behaviour in the main transition and rubbery region was investigated for polyurethane networks produced from triisocyanate and diols based on diethanolamine derivatives and poly(oxyethylene). The effects of altering main and side chain length of diols and initial molar ratio of hydroxy [OH] to isocyanate [NCO] groups, r H, on the shape and temperature position of mechanical functions were determined. While the values of functions in the rubbery region are predominantly determined by the concentration of the network chains, the shape of the functions associated with the main transition region depends also on the topology of the network chains (especially the presence of dangling chains). The temperature position of the main transition depends on both submolecular (length of diol backbone and side chain, polarity of diol and concentration of [NCO] groups) and molecular (number and structure of the network chain) parameters.