The influence of the structure of t

The influence of the structure of the soft segment on tensile strength and
elongation is related to the intermolecular association and crystallization during
stretching. The effect of the soft segment is pronounced mainly in polymers with
a continuous soft phase i.e. above 50% SSC. Generally, polyurethanes based on
polyesters have higher tensile strengths than those based on corresponding
polyethers and polybutadiene oligomers. Poly(ethylene adipate) polyester polyurethanes
were found to have better tensile properties than poly(ethylene-cobutylene
adipate) or PCL polyurethanes, which suggests that crystallization and
relative density of ester bonds, i.e. polarity, play decisive roles. 2t4 Although
numerous data have been published on the effect of various components on the
properties of polyurethane elastomers, direct comparison of data from different
sources is often not possible.