{TAIL ~ Such systems} typically also include a quasi prepolymer of an isocyanate and an active hydrogen containing material, and at least one amine resin, and {HEAD ~ preferably an amine terminated chain extender} 
{ TAIL ~ Such systems } typically also include a quasi prepolymer of an isocyanate and an active hydrogen containing material , and at least one amine resin , and { HEAD ~ preferably an amine terminated chain extender }
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