POLY 124 |
| The step-growth click coupling of well-defined block copolymers synthesized by atom transfer radical polymerization (ATRP) was used to prepare multisegmented block copolymers. α,ω-Diazido-terminated polystyrene-b-poly(ethylene oxide)-b-polystyrene was coupled with propargyl ether in DMF in the presence of a CuBr/N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA) catalyst. Additional multisegmented materials were prepared by click coupling of propargyl ether with another diazido-terminated triblock copolymer, poly(n-butyl acrylate)-b-poly(methyl methacrylate)-b-poly(n-butyl acrylate), and a diazido-terminated pentablock copolymer, polystyrene-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-polystyrene. The formation of a product of higher molecular weight and broader molecular weight distribution was verified by triple-detection size exclusion chromatography. Differential scanning calorimetry and dynamic mechanical analysis revealed that the amphiphilic block copolymer behaves as a viscoelastic fluid, while its corresponding multiblock copolymer is an elastic material. The multisegmented block copolymers with partially miscible segments exhibit higher glass transition temperatures than their precursors. |
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General Papers: Functional Materials
6:00 PM-8:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Polymer Chemistry |