Synthesis of Multibranched Polymers by Linking Reactions of Linear Block Copolymers with Pendant Vinyl Groups by Conventional Radical Polymerization

Polymer linking reactions of block copolymers with pendant vinyl groups were examined based on conventional radical reaction. For example, sequential living cationic polymerization with the HCl/ZnCl2 initiating system gave a block copolymer of isobutyl vinyl ether [IBVE, CH2=CHOCH2CH(CH3)2] and a vinyl ether with the methacrylate-type double bond [VEM, CH2=CHOCH2CH2OCOC(CH3)=CH2]. The resulting block copolymer [DP(IBVE) = 15–30, DP(VEM) = 5–10] is treated with 2,2’-azobisisobutyronitrile (AIBN) in toluene at 60 °C to give a soluble polymer with multibranched structures. The Mw [Mw(LS)] of the product star polymers determined by GPC on-line multiangle laser light scattering (GPC-MALLS), and the number of branches calculated from Mw(LS) ranged from 3.5 × 104 to 34 × 104, and from 15 to 140, respectively. This is a possible method for the preparation of functionalized nanospheres.