Moisture_cure_polyurethane
Moisture-cure polyurethanes -- or polyurethane prepolymer -- are isocyanate-terminated prepolymers that are formulated to cure with ambient water.[1] Cured PURs are segmented copolymer polyurethane-ureas[2] exhibiting microphase-separated morphologies. One phase is derived from a typically flexible (subambient glass transition temperature, Tg) polyol that is generally referred to as the “soft phase”. Likewise the corresponding “hard phase” is born from the di- or polyisocyanates that through water reaction produce a highly crosslinked material with softening temperature well above room temperature.