The current state-of-the-art strategy formaking polymer colloids usually employsradical-initiated emulsion or miniemulsionpolymerization. Despite its success, it haslimitations: This strategy only works well with a

limited number of monomers such asacrylates, methacrylates, and styrenics.

It will break the double bonds ofmonomers, leaving no unsaturation in thepolymer backbone (typically only sidegroups can be used for furtherfunctionalization).

We challenged ourselves to address theseissues via introducing metathesis chemistryinto the preparation of polymer colloids.

Background

Catalyst design

(a) Further investigate the reactivity, efficiency and partitioning behavior of catalyst;

(b) Deepen the understanding of kinetics in miniemulsion polymerization including nucleation, chain propagation, chain transfer, etc.;

(c) Introduce new monomers.

Experimental

Future Work

Motivation

Experimental

Polymer Latexes via Ring-opening Metathesis Polymerization (ROMP)

Chunyang Zhu1, Xiaowei Wu2, Cathleen M. Crudden2, Michael F. Cunningham1,2

1. Department of Chemical Engineering, Queen’s University, Kingston, Ontario, Canada, K7L 3N62. Department of Chemistry, Queens’s University, Kingston, Ontario, Canada, K7L 3N6

[1] Hong, S. H., & Grubbs, R. H. (2006).Journal of the American Chemical Society,128(11), 3508–9.

Ontario Research Chairs Program

Why ring opening metathesis polymerization (ROMP)?

Traditional radical polymerization methodsresult in a reduction in functionality (alkenesto alkanes). In contrast, ROMP retains all ofthe functionality of the starting olefins,which allows potential applications in manyfields such as biomaterials, liquid crystallinepolymers, self-healing materials, degradableplastics, and nanocomposites.

How does ROMP work in the aqueous phase?

Current ROMP is typically employed inorganic solvents since the catalysts arehydrophobic and have limited long-termstability in water.[1] Here we developed anovel ROMP process in aqueous dispersionswhich eliminates the use of organic solventsand enhances heat transfer and mixing. Thisnew process is based on our modifiedcatalysts. The development is believed toachieve three objectives:

(a)Enabling the preparation of latexes viaROMP, which is currently not possible inindustry;

(b)Eliminating the use of large amounts ofvolatile organic compounds (VOCs);

(c) Improving the efficiency and lowering thecost of the manufacturing process.

(a) A novel water-soluble metathesis catalyst was customized for miniemulsion polymerization.

(b) A procedure was developed for ring opening metathesis polymerization in miniemulsion.

(c) Well-defined polymer latexes were obtained with stable colloidal behavior and particle size, which can be used as intermediates for further modification.

After shaking

Solubility Stability Reactivity

1H NMR of new catalyst (D2O) 1H NMR of ROMP (CD2Cl2)

Kinetic study

LnMR

metalalkylidene

+

LnMR

[2+2]LnM

RLnM R

metallacyclobutane

LnM R + n LnM Rn+1

LnM Rn+1

+ X=Y LnM=X Y Rn+1

+

Initiation:

Propagation:

Termination:

𝑅𝑅𝑝𝑝 = −𝑑𝑑 𝑀𝑀𝑑𝑑𝑑𝑑 = 𝑘𝑘𝑝𝑝 𝑅𝑅𝑅𝑅 𝑀𝑀

ln𝑀𝑀 0

𝑀𝑀 𝑡𝑡= ln

11 − 𝑥𝑥

= 𝑘𝑘𝑝𝑝 𝑅𝑅𝑅𝑅 𝑑𝑑

Preparation of monomer miniemulsion

HD/COD/Triton-X100/H2O

Time (min)

0 10 20 30 40 50 60 70

Z-av

g (d

. nm

)

50

100

150

200

250

PDI

0.0

0.1

0.2

0.3

0.4

0.5

HD/COD/CTAB/H2O

Time (min)

0 10 20 30 40 50 60 70

Z-av

g (d

. nm

)

60

80

100

120

140

160

180

200

PDI

0.0

0.1

0.2

0.3

0.4

0.5

HD/NB/Triton-X100/H2O

Time (min)

0 10 20 30 40 50 60 70

Z-av

g (d

. nm

)

50

100

150

200

250

PDI

0.0

0.1

0.2

0.3

0.4

0.5

HD/NB/CTAB/H2O

Time (min)

0 10 20 30 40 50 60 70

Z-av

g (d

. nm

)

60

80

100

120

140

160

180

200

PDI

0.0

0.1

0.2

0.3

0.4

0.5

LogM

3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4

d(w

t)/d(

LogM

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Conversion

0.0 0.2 0.4 0.6 0.8 1.0

Mn

0

10000

20000

30000

40000

50000

60000

PDI

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4t = 1 hrt = 2 hrt = 3 hr t = 4 hrt = 5 hrt = 7 hr t = 12 hr

ROMP in miniemulsion

Ar

Ar

H2O/Surfactant

Monomer/costabilizer

Ar

Monomer miniemulsion

Sonication Catalyst

Ar

Polymer latex

cannula

cannula

Monomer emulsion

Time (hr)

0 20 40 60 80

Z_av

g (n

m)

100

120

140

160

180

200

PDI

0.0

0.1

0.2

0.3

0.4

0.5

Discussion

References

ROMP of 1,5-cyclooctadine in CD2Cl2 using the new catalyst.

Evolution of molecular weight and PDI with conversion(solution polymerization).

Z-average diameter and PDI values of various monomer miniemulsions.

ROMP in miniemulsion with air-free technique.

Evolution of MWD, Mn and PDI with reaction time (miniemulsion polymerization).

Z-average diameters during polymerization.

[Ru]n

n

Time (hr)

0 20 40 60 80

Conv

ersio

n

0.0

0.2

0.4

0.6

0.8

1.0

Time (hr)

0 20 40 60 80

ln[1

/(1-x

)]

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Conversion

0.0 0.2 0.4 0.6 0.8

Mn

0.0

2.0e+4

4.0e+4

6.0e+4

8.0e+4

1.0e+5

1.2e+5

PDI

0

1

2

3

4

MnTarget MnPDI

LogM

3.5 4.0 4.5 5.0 5.5 6.0 6.5

dwt/d

LogM

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4 60 h48 h36hr24 h12 h

Conversion and normalized conversion plots with time (miniemulsion polymerization).

O

O

OOHO

ON

N

BrO

O

O

Prof. CruddenProf. Cunningham Chunyang ZhuDr. Wu