Synthesis and Characterization of Comb and CentipedeMultigraft Copolymers PnBA-g-PS with High Molecular Weight Using Miniemulsion Polymerization.

Comband centipede multigraft copolymers, poly(n-butylacrylate)-g-polystyrene (PnBA-g-PS) with PnBA backbones and PS side chains,were synthesized via high-vacuum anionic polymerization and miniemulsionpolymerization. Single-tailed and double-tailed PS macromonomers weresynthesized by anionic polymerization and Steglich esterification.Subsequently, the copolymerization of each macromonomer and nBA was carried out in miniemulsion, and multigraft copolymerswere obtained. The latex particles of multigraft copolymers were characterizedusing dynamic light scattering. The molecular weights of macromonomersand multigraft copolymers were analyzed by size exclusion chromatography.Moreover, the molecular weights and structures of macromonomers wereinvestigated by matrix-assisted laser desorption/ionization time-of-flightmass spectrometry and 1H nuclear magnetic resonance spectroscopy.The weight contents of PS in comb and centipede multigraft copolymerswere calculated by 1H nuclear magnetic resonance spectroscopy.The thermal properties of multigraft copolymers were characterizedby thermogravimetric analysis and differential scanning calorimetry.The microphase separation of multigraft copolymers was observed byatomic force microscopy and transmission electronic microscopy. Rheologicalmeasurements showed that comb and centipede multigraft copolymershave elastic properties when the weight content of PS side chainsis 26–32 wt %. Centipede multigraft copolymers possess betterelastic properties than comb multigraft copolymers with the similarweight content of PS. These findings are similar to previous resultson poly(isoprene-g-polystyrene) comb and centipedecopolymers made by anionic polymerization. [ABSTRACT FROM AUTHOR]