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