The major curative for hot cast elastomers from methylene diphenyl diisocyanate prepolymers is generally 1,4-butane diol, due to the symmetry and crystallinity of the hard segments created as these materials react.
Ethylene glycol, however, is a comparatively inexpensive alternative to 1,4-butane diol, which reacts with the same prepolymers to form hard segments with much higher melting points and comparatively better critical phase separation.
In this study, the advantages and differences in hard segment melting point, reactivity and physical properties of hot cast elastomers cured with ethylene glycol and 1,4-butane diol are examined.