tailieunhanh - Living polymerization
Polymers in everday use: Mechanical properties; New applications; Personal care products; Pharmaceutical Applications; BASF, Unilever, Geltex, Avecia, etc. | Living polymerization Polymers in everday use Mechanical properties New applications Personal care products Pharmaceutical Applications BASF, Unilever, Geltex, Avecia, etc Control over Polymer architecture Graft Copolymers Star copolymers Dendrimers Non covalent crosslinking Branching Narrow MWD Blocks Control Test for Living Polymerisation Living Polymerisation Anionic Cationic Ring Opening Living Polymerisation Rate of termination 0 Rate of Initiation > Rate of Propagation PDi (Mw/Mn) = 1 + 1/DP Living systems *constant number of polymer chains *no permanent chain stopping reactions *dormant and active state *control of chain-growth *narrow MWD (Poisson) * vs. monomer conversion is linear Living Polymerization Conversion Mn Mn= [M]0 [I]0 Conv. Mm Mn Structure Radical reactions ? Free Radical Polymerisation Living and Controlled Polymerisations Living systems constant number of polymer chains no permanent chain stopping reactions dormant and active state control of chain-growth narrow MWD (Poisson) vs. monomer conversion is linear K. Matyjaszewski: Macromolecules 1997, 30, p7697; 7042; 7034; 7348; 8161; 7692; 6507, 6513, 6398 JACS 1997, 119, p674 V Percec: Macromolecules 1997, 30, p6705, 8526 M Sawamoto: Macromolecules 1997, 30, p2244, 2249 Teyssie: Macromolecules 1997, 30, p7631, Haddleton: Macromolecules 1997, 30, p2190 Suppressing radical termination Rt/Rp =kt [P•]2/kp[M][P•] =kt[P•]/kp[M] ATRP Systems Metal Ligand Initiator CuBr, CuCl Bipyridine Multidentate amine RuBr2 PPh3 + Al(OiPr)3 FeBr2 PPh3 NiBr2 PPh3 PdBr2 PPh3 Macromolecules, 30 (25), 7697 -7700, 1997. A: PS standard B: PS by ATRP C: PS by AIBN Patten, ., Xia, J, Abernathy, T., Matyjaszewki, K. Science 1996, 272, 866. A: Synthesis of polymers with controlled molecular weight 2. ATRP Applications Factors affecting the molecular weight control Fast initiation Rapid deactivation Narrow MWD C-XInitiator C-Xpolymer Initiator matches Monomer Rapid deactivation not go too high Kp - Temperature B: Synthesis block copolymers Macroinitiator method C: Synthesis of star polymers Matyjaszewski, K., Miller, P. J. Pyun, J. Kickelbick, G. Diaamanti, Macromolecules 1999, 32, 6526 Macromolecules, 31 (20), 6762 -6768, 1998 Jiro Ueda, Masami Kamigaito, and Mitsuo Sawamoto Macromolecules, 31 (20), 6756 -6761, 1998 Hiroko Uegaki, Yuzo Kotani, Masami Kamigaito, and Mitsuo Sawamoto D: Hyperbranched Polymers Monomer-Initiator E. Synthesis of End-functionalized Polymers Challenges for ATRP Too much “catalyst” leads to problems of cost and residual metal in products. Rate can be accelerated; Reduction of copper(II) to copper(I) . disproportionation with copper(0) - Matyjaszewski Addition of rate enhancers . acid, alcohols Use of mildly co-ordinated solvents However, for many applications we require Much lower levels of metal Recycling of metal Acceptable rates of polymerisation Catalyst supporting Solution to the Problem ? Mn and PDI vs conversion in MMA polymerization by supported catalysts Haddleton, Chem. Commun. 1999, 99. WHY? Develop high reactive catalysts Future development Graft Copolymers Brush Copolymer Block copolymer side chains Materials 2-(2-Bromoisobutyryloxy) ethyl methacrylate (BIEM) 2-(Dimethylamino) ethyl methacrylate (DMAEMA) Hydroxylethyl methacrylate (HEMA) Ethyl -2-bromoisobutyrate HAuCl4,4H2O NaBH4 Potassium persulfate (KPS) Synthesis of PDMAEMA brushes on the surface of colloid particles by ATRP.
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