Phase structure of polyetherpolyol‐4,4′‐diphenylmethane diisocyanate‐based reaction injection molded (RIM) polyurethanes

A series of polyetherpolyol−4,4/‐diphenylmethane diisocyanate based polyurethanes were prepared by reaction injection molding (RIM). The degree of phase separation and morphology, which govern the mechanical properties, was investigated by X‐ray scattering, dynamic mechanical spectroscopy, and electron microscopy. The phase reversion occurred at just a 70 weight percent concentration of the based reagent. The degree of phase separation increased with the molecular weight of polypropyleneglycol and decreased with the ethyleneoxide capping content. Morphology was influenced by injection rates.