Controlled Polymerisation

1
Controlled Polymerisation

• D M Haddleton
• CH404
• Synthetic Chemistry III
• 2002 - 2003

2
Course Structure

• Introduction/Living Polymerisation
• Nitroxide Mediated Radical Polymerisation NMRP
• RAFT
• Transition Metal Mediated Radical Polymerisation
• Catalytic Chain Transfer Polymerisation
• Case Studies

3
Lecture Plan

• Introduction
• RAFT (Reversible Addition Fragmentation Transfer)
• ATRP, Transition Metal Mediated Polymerisation
• Catalytic Chain Transfer Polymerisation (CCTP)
• Case Studies

4
Task between Lectures

• 5 People involved in the chemistry
• 5 Companies
• 5 Potential Applications
• Major Limitation
• The best Paper in the area

5
Week 10 topics

• Light emitting polymers
• Why are IBM Leaders in Living Radical
  Polymerisation?
• Glycopolymers
• Polymers used in therapeutics

6
Essay title

• Compare and contrast living radical
  polymerisation methods from an experimental point
  of view.

7
Polymers in everday use

• Mechanical properties
• New applications
• Personal care products
• Pharmaceutical Applications
• BASF, Unilever, Geltex, Avecia, etc

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Control over Polymer architecture

• Graft Copolymers
• Star copolymers
• Dendrimers
• Non covalent crosslinking
• Branching
• Narrow MWD
• Blocks

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Control
10
Control of Macromolecular Structure
? Topology
? Composition
11
Innovations to Control RP

• Reversible homolytic cleavage
• Nitroxide-Mediated LRP (CSIRO, Georges, Fukuda,
  Hawker,...)
• Transition Metal Mediated LRP (ODriscoll,
  Wayland, Sawamoto, Matyjaszewski, Percec,
  Haddleton,...)
• Chain transfer processes
• Addition Fragmentation (CSIRO)
• RAFT (CSIRO)
• Catalytic Chain Transfer Polymerisation (Smirnov,
  Gridnev, Hawthorne, Janowicz, CSIRO, Haddleton,
  Davis,...)
• Combination of both
• Iniferters (Otsu)

12
Living Polymerisation

• Rate of termination ? 0
• Rate of Initiation gt Rate of Propagation
• Then
• PDi (Mw/Mn) 1 1/DP

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Test for Living Polymerisation
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Living Polymerisation

• Anionic
• Cationic
• Ring Opening

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Commercial impact of living/controlled
polymerisation

• Anionic Polymerisation is the most established
  form of living polymerisation
• Although discovered in 1956 commercial
  applications have probably not lived up to
  expectations
• Notable exception is styrene-diene block/star
  copolymers (Kraton rubbers)
• Generally anionic polymerisation requires low
  temperatures, solvents which do not chain
  transfer and extremely pure solvents and reagents.

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Group Transfer Polymerisation
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Free Radical Polymerisation
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Nitroxide Mediated Radical Polymerisation
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Reversible Homolytic Dissociation

• Covalent adduct
• Persistent radical

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Acc. Chem. Res., 30 (9), 373 -382, 1997
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Variation in experimentally determined molecular
weight, Mn, and the theoretical molecular
weights for thepolymerization of styrene at 125 C
using varying amounts of the unimolecular
initiator 9.
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CRP of Styrene in Bulk

• T 393 K
• L0 5 10-2 M

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Library of alkoxyamine structures evaluated as
initiators for the living free radical
polymerization of styrene and n-butyl acrylate.
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TEMPO
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Living Polymerisation of Dienes
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Reversible Addition Fragmentation Polymerisation

• RAFT

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RAFT Polymerisation
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Macromolecules, ASAP Article 10.1021/ma991451a
S0024-9297(99)01451-5 Web Release Date January
6, 2000
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GPC traces of (a) PMA prepared using 5 and (b)
the same PMA treated with ethylenediamine in THF
at room temperature
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Generalized Addition-Fragmentation
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Addition - Fragmentation
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Atom TransferPolymerisation
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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
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Macromolecules, 30 (25), 7697 -7700, 1997.
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Macromolecules, 31 (4), 1064 -1069, 1998
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Macromolecules, 31 (20), 6762 -6768, 1998
Jiro Ueda, Masami Kamigaito, and Mitsuo Sawamoto
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Macromolecules, 31 (20), 6756 -6761, 1998
Hiroko Uegaki, Yuzo Kotani, Masami Kamigaito,
and Mitsuo Sawamoto
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Macromolecules, 32 (7), 2204 -2209, 1999
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Reaction rate dependence on the Cu(I)
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Too much catalyst leads to problems of cost
and residual metal in products. Rate can be
accelerated Reduction of copper(II) to
copper(I) e.g. disproportionation with
copper(0) - Matyjaszewski Addition of rate
enhancers e.g. 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
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Synthesis of Initiators from alcohols
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?- Functional polymers from functional initiators
based on phenols
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Catalytic Chain Transferfor Molecular Weight
Control inFree-Radical Polymerisation
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Measurement of Chain Transfer Constants
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Polymerisation of MMA at 60 C with COBF
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Types of Catalysts
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Mechanism of CCTP
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CCT Agents
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Acrylate Monomers
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Comparison of Catalysts
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Generalized Addition-Fragmentation
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Addition - Fragmentation
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Further reaction of CCTP macromonomer products
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