The block copolymers may be prepared by selectively hydrogenating substantially 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 {HEAD ~ selective hydrogenation} to enable {TAIL ~ the vulcanization} of the block copolymer 
to enable
The block copolymers may be prepared by selectively hydrogenating substantially 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 { HEAD ~ selective hydrogenation } to enable { TAIL ~ the vulcanization } of the block copolymer
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