Hyperbranched polymer through initiator-fragment incorporation radical copolymerization of divinyl adipate with allyl acetate: Synthesis, characterization, dye solubilization, metal-nanoparticle stabilization, and porous film formation

Abstract

The copolymerization of divinyl adipate (DVA) as an effective cross-linker with allyl acetate (AAc) as a degradative chain transfer reagent was carried out at 70 and 80 C in benzene using dimethyl 2,2′-azobisisobutyrate (MAIB) of high concentrations as initiator. When the MAIB concentration as high as 0.60 mol/L was used, the copolymerization of DVA (0.20 mol/L) and AAc (0.50 mol/L) proceeded homogeneously without any gelation to give soluble copolymers in a yield of about 30% based on the total weight of DVA, AAc, and MAIB. The copolymer formed in the copolymerization at 80°C for 6 h consisted of the DVA units with (3 mol %) and without (24 mol %) double bond, the AAc unit (35 mol %), and the methoxycarbonylpropyl group (38 mol %) from MAIB. Such a large fraction of the incorporated initiator-fragment as terminal group indicates that the copolymer has a hyperbranched structure. The copolymer showed an upper critical solution temperature (38°C on cooling) in a tetrahydrofuran (THF)-water [2:1 (v/v)] mixture, and also exhibited potentials in solubilization of Rhodamine 6G as a dye probe and stabilization of metal nanoparticles. A porous film was obtained simply by casting a copolymer solution in THF.