Second, recovering the metallated polymer in {TAIL ~ the active form} allows {HEAD ~ concentration} thereof for further reaction 
Second , recovering the metallated polymer in { TAIL ~ the active form } allows { HEAD ~ concentration } thereof for further reaction
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH