1,3-Cyclohexadiene Polymers. 2. Near-Monodisperse Star and Star-Block Polymers Based on Poly(1,3-cyclohexadiene)

The synthesis of well-defined, near-monodisperse, three-arm star and star-block copolymers based on poly(1,3-cyclohexadiene) (PCHD) is described. The stars were prepared by the reaction of living anionic chain ends of PCHD, poly(styrene−1,3-cyclohexadiene) (PS-PCHD), and poly(1,3-cyclohexadiene−styrene) (PCHD-PS) with CH3SiCl3 in benzene. 1,4-Diazabicyclo[2.2.2]octane (DABCO) was used to control the anionic polymerization of 1,3-CHD; it also acted as a promoter during the linking reaction. The star polymers were fractionated to remove excess arm material and thoroughly characterized by size exclusion chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and light scattering.