| abstract |
An improved process for free radical polymerization is produced making it possible to control the growth steps of a polymerization to produce homopolymers and copolymers, including block and graft copolymers. The process uses a long half-life radical initiators and compounds which have the structure of formula I ##STR1## wherein X is a group having at least one carbon atom and is such that the free radical X is capable of polymerizing the unsaturated monomer by free radical polymerization, and the radical functionality resides on the or one of the carbon atoms, R 1 , R 2 , R 5 and R 6 represent the same or different straight chain or branched substituted or unsubstituted alkyl groups of a chain length sufficient to provide steric hindrance and weakening of the O--X bond, and R 3 and R 4 represent the same or different, straight chain or branched, substituted alkyl groups or R 3 CNCR 4 may be part of a cyclic structure which may have fused with it another saturated or aromatic ring, the cyclic structure or aromatic ring being optionally substituted. |