While almost any diisocyanate may be used, {HEAD ~ TDI} and MDI are preferred because of {TAIL ~ their low cost} 
preferred because of
While almost any diisocyanate may be used , { HEAD ~ TDI } and MDI are preferred because of { TAIL ~ their low cost }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL