END-FUNCTIONALIZED POLYMERS OF STYRENE AND P-METHYLSTYRENE BY LIVING CATIONIC POLYMERIZATION WITH FUNCTIONALIZED INITIATORS

A series of a-end-functionalized polymers of styrene and p-methylstyrene were synthesized by living cationic polymerizations in CH2Cl2 at -15-degrees-C initiated with the HCl adducts [2; CH3CH(OCH2-CH2X)Cl; X = chloride, benzoate, acetate, phthalimide, methacrylate] of vinyl ethers carrying pendant substituents X that serve as the terminal functionalities in the products. When coupled with SnCl4 (activator) in the presence of nBu4NCl, these functionalized initiators (2) quantitatively initiated living polymerizations, where the carbon-chlorine bond of 2 was activated by SnCl4. The number-average molecular weights (M(n)BAR) of the polymers increased in direct proportion to monomer conversion, and the molecular weight distributions were narrow (M(w)BAR/M(n)BAR < 1.2). H-1 NMR analysis showed all the polymers to possess controlled molecular weights (DP(n)BAR = [M]0/[2]0) and end functionalities close to unity (i.e., F(n) congruent-to 1; one terminal functionality X per chain).