. . . . "By a similar technique, a radial block copolymer can be formed having the formula (A-B)n X, wherein X is the hub or central, polyfunctional coupling agent and n is a number greater than 2. (If n were 2, the polymer would be A-B-X-B-A, which is equivalent to the A-B-A structure described previously and is essentially linear.) Using the coupling agent technique, the functionality of X determines the" .