X-ray investigations concerning the physical structure of crosslinking in urethane elastomers. III. Common structure principles for extensions with aliphatic diamines and diols

Physical crosslinking of urethane elastomers is essentially based on statistical systems of hydrogen bonds within the hard segment domains. Two dimensional models of these systems, given in previous papers, are now replaced by three-dimensional models in the case of butane diol and pentane diol extenders, respectively. A suggestion is made for the transverse crosslinking mechanism with diamine extenders. Taking into account the conditions for three-dimensional hydrogen bonded systems a correlation between the cross-linking structure and heat-distortion temperature of diamine and diol extended elastomers is obtained.