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