For example, in an inert atmosphere such as argon or nitrogen the formation of the block copolymer can range from about minus 40??? C. to about 100??? C., desirably from about 0??? C. to about 90??? C., and preferably from about 25??? C. to about 45??? C. As with the formation of block copolymers from an initiator containing halogen-containing polymers such as polyvinyl chloride, block copolymers