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