Cours Ch Hl[3] _ Atrp

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LIVING POLYMERIZATION

Hà Thúc Huy

Khoa Hóa - ĐHKHTN

Cao học Hóa LýTổng hợp & Biến tính poloymer



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

•Molecular Weight

(Chain Length and Polydispersity)

•Chain Architecture

(Block, Comb, etc)

•

Functionality

•Rate / Exotherm

X

Y

Macromonomer

Telechelic

Block

Graft



Radical reactions

P1 P2+

P1 P2

P1 P2+

P M P M

P S P S

P Px PxP

+

+

+

+

+

+

?



Test for Living Polymerisation

0 20 40 60 80 100

M n

% Conversion

kp[Pol*]

l n [ M ] 0 / [ M ]

time



Living Polymerisation

•Anionic

•Cationic

•Ring Opening




• 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)

*<Mn> vs. monomer conversion is

linear




◊ No Termination

◊ No Chain Transfer

INITIATION

I* + M→IM* k i

PROPAGATION

IM* + M→IMM* k p1

IM n* + M→IM nM* k pn



Rate of Initiation = k i[I][M]

Rate of Propagation = k p[M*][M]

[M*] = [I]

Integration leads to,

ln[M]0/[M] = k p[M*]t

As the rate of termination = 0

[M*] is constant

Thus a plot of ln[M]0 /[M] vs t is linear



Degree of Polymerisation = Dpn

i.e. Dp

Dpn = [M]/[I] @ 100% conversion

Mn = Dpn x M0

(M0 = mass of the repeat unit)

Thus a plot of Mn vs % Conversion is linear for

a living polymerisation



If Rate of initiation (R i)≈or > Rate of

Propagation (R p)

and both R i and R p > Rate of termination (R t)

(Ideally R t = 0)

Then

PDi (MWD, Mn/Mw) is narrow and a Poisson

distribution.

PDi = 1+1/[DPn]

e.g. For a polymer with DPn = 100, PDi = 1.01



ATRP ATOM TRANSFER RADICAL

POLYMERIZATION



Living Polymer ization

Conversion

M n

Mn=

[M]0

[I]0

× Conv.×Mm

• Mn

• Structure



Free Radical Polymerisation•Widely used industrially

•Advantages:

- Very Robust Technique

- Wide range of monomers and functionality’s

Almost anything with a double bond

- Wide range of operating conditions

- Aqueous Media: Emulsion polymerisation

•Disadvantages

•Highly non-selective reaction Non-trivial product control



Living and ControlledPolymerisations

• Living systems – constant number of polymer chains

– no permanent chain stopping reactions

– dormant and active state – control of chain-growth

– narrow MWD (Poisson)

– <M n> vs. monomer conversion is linear



R-X + M(n)↔R* + M(n+1)-X

X = Cl, Br

R* can propagate or terminate

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 =k t [P•]2/k p[M][P•]

=k t

[P•]/k p

[M]

ATRP MechanismATRP Mechanism

CuBr/L + Br P CuBr 2/L+ P•



Cu

MLigand



ATRP Systems

Metal Ligand Initiator

CuBr, CuCl Bipyridine

Multidentate amine

RuBr2 PPh3 + Al(OiPr)3

FeBr 2 PPh3

NiBr 2 PPh3

PdBr 2 PPh3

X

X

O

O

X

O

O

SO2Cl



Macromolecules, 30 (25), 7697 -7700, 1997.



A: PS standard

B: PS by ATRP

C: PS by AIBN

Patten, T.E., Xia, J, Abernathy, T., Matyjaszewki, K. Science 1996 , 272, 866.

A: Synthesis of polymers with controlled molecular weightA: Synthesis of polymers with controlled molecular weight

2. ATRP Applications



Factors affecting the molecularFactors affecting the molecular

weight controlweight control

• Fast initiation

• Rapid deactivation

Narrow

MWD



SO2Cl

X

O

OX

O

O

X

OBr

O

O

O

O

O

C-XInitiator ≥ C-X polymer

Initiator matches Monomer



Rapid deactivation

1 +Kp[R-X]

Kd[CuX2]

2

Conv1

Mw

Mn

=

[CuX2][P ]

[CuX][P-X]=Kd

Conv.-can not go too high

Kp - Temperature

B: Synthesis block



B: Synthesis block

copolymers

Macroinitiator methodR-X +

CuX/LM X1

M2CuX/L

X

X-R-X+ M1 CuX/L XX

X

CuX/L 2M

X

AB

ABA



C: Synthesis of star polymers

O

O

Br

O

Br

Br

O

O

O

O

O

Br

Br

O

O

O

O

Br

Br

O

O

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

Cl

O

O

Br

O

O

O

O

Br

O

O

Monomer-Initiator



A

B*

* * *

*

*

*

*

*

*

*

**

*

*

*

*

* *

*

*

*

*

*

*

* *

**

*

**

*

* *

*

*

*

*

*

**

*

*

*

*

*

A*

B*

A*BB*

AA



E. Synthesis of End-functionalized Polymers

O OBr

O

O NH

Cl

Cl

ClO

O

ClO

HO OBr

O

St, MMA, MA

St, MMA

MA (at low conversion)

MMA

St



Low catalystefficiency

High catalystresidual

Deep color in product

Purification Catalyst and

ligand waste

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) e.g. disproportionation

with copper(0) - Matyjaszewski

Addition of rate enhancers e.g. acid, alcoholsUse 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

PS

or

SiN

N

Cu

Br

0

5000

10000

15000

0 20 40 60 80

Conversion (%)

M n

1

1.5

2

2.5

3

Mw / Mn

Theor. Mn

Haddleton,

Chem. Commun. 1999, 99.



Cu

Support

Catalyst

Spacer

NN

X

ClN

O

O

NH2

N

N

Crosslinked PSTY bead with 2 %

chlorostyrene

PotassiumPhthalimide

DMF

N2H4

2-Pyridine carbaldehyde

Supported catalysts for ATP



WHY?WHY?

1 +Kp[R-X]

Kd[CuX2]

2

Conv

Mw

Mn=



Catalyst

Concentration.Catalyst

residual Color

Develop high reactive catalysts

Future development



Materials

2-(2-Bromoisobutyryloxy) ethylmethacrylate (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.

Cours Ch Hl[3] _ Atrp

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