The block copolymers may be prepared by selectively hydrogenating substantially {HEAD ~ all the I polymer units} of a precursor block copolymer with a sufficient number of D units in the D polymer blocks retaining their unsaturation on selective hydrogenation to enable the vulcanization of {TAIL ~ the block copolymer} 
The block copolymers may be prepared by selectively hydrogenating substantially { HEAD ~ all the I polymer units } of a precursor block copolymer with a sufficient number of D units in the D polymer blocks retaining their unsaturation on selective hydrogenation to enable the vulcanization of { TAIL ~ the block copolymer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH 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