For example, the chain transfer agent may be an alkyl, dialkyl, cycloalkyl or a dicycloalkyl amine having the general formula: or a cyclic amine having the general formula: In these formulas, R1 and R2 independently are an alkyl, cycloalkyl or aralkyl having from 1 to about 20 carbon atoms, and R3 is a divalent alkylene, bicycloalkane, substituted alkylene, oxy- or N-alkylamino-alkylene group havi