Experimental Investigation of AGET ATRP of MMA in

Two-Step Emulsion SystemKishor N. Up. Regmi, Ramdhane Dhib, Mehrab Mehrvar

Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada

Reactor System

NSERC and Department of Chemical Engineering,

Ryerson University for financial support.

Introduction Results

Objectives

Concluding RemarksSynthetic Procedure

Atom transfer radical polymerization (ATRP) is one of the most popular method of CRP. Currently

there is exponential growth in the research of ATRP as it allows the production of polymers having

controlled features (low MWD, high chain end functionality) with relative ease.

Polymers synthesized by ATRP can be used as lubricants, surfactants, adhesives, inks, gels, dispersants,

additives, thermoplastic elastomers, as well as for biomedical applications like drug delivery and

artificial bones.

ATRP in aqueous dispersed media has several advantages as compared to bulk and solution

polymerization like: use of environmentally friendly and economical dispersant, very efficient heat

transfer and less viscous reaction medium allowing high conversion.

The literature on ATRP in aqueous dispersed media (emulsion ATRP) though not extensive is growing

rapidly. The polymer chemistry and other kinetic/mechanistic aspects of ATRP in emulsion are still not

well understood

• Conduct the single-step and two-step emulsion AGET ATRP of MMA in a stirred tank reactor using

commercially available chemicals: CuBr2, dNbpy, EBiB, AA and Brij 98.

• Investigate the effect of single-step and two-step emulsion system on the stability of latex, conversion

of the monomer and molecular weight distribution (MWD) of the polymer.

• Generate a source of reliable experimental data (based on the statistical analysis) which will help in

the better understanding of the system.

𝑃𝑛 − 𝑋 + 𝑀𝑡𝑛/𝐿

𝐾𝑎𝑐𝑡

𝐾𝑑𝑒𝑎𝑐𝑡

𝑃𝑛. + 𝑋 −𝑀𝑡𝑛+1/𝐿

Experimental Condition

Acknowledgement

• Experimental results indicate that it is possible to conduct

ATRP in single–step and two-step emulsion system with

limited presence of air. However it is very hard to get stable

latex system without aggregation/coagulation, especially at

higher conversion for both systems.

• Control of polymerization is comparatively good in two-step

emulsion than in single-step emulsion, as indicated by low

PDI even at low conversion and low number average

molecular weight.

• Statistical analysis shows that: Temperature has the profound

effect on all responses (conversion, Mn and PDI). EBiB is the

important factor for Mn but not for other two effects. Catalyst

complex has medium effect on all responses. Brij 98 is an

important factor for conversion and PDI but not for Mn.

Ascorbic acid has an important effect on PDI, however its

effect on other two responses is not much important.

MechanismSingle-step emulsion Two-step emulsion

From preliminary investigation it was found that, livingness (narrow PDI and targeted

molecular weight) is preserved better in two-step emulsion system than that in single-

step emulsion system, thus DOE was prepared based on two-step emulsion system.

Design specification: Five factor two-level fractional factorial experimental

design with resolution 5 (2v5-1 ) having 5 center points

Independent variable

Level and range of

independent variable

Actual

Variable

Coded

variable -1 0 1

Temp (oC) X1 50 55 60

Brij 98 (g) X2 15.0000 16.500018.000

0

Ascorbic

Acid (g)X3 0.0600 0.0660 0.0720

EBiB (g) X4 0.3987 0.4486 0.4984

CuBr2/dNBp

y (g/g)X5

0.0838/0

.3065

0.0922/

0.3372

0.1006/

0.3678

Following condition is kept constant for

all the runs (Two-step emulsions)

N2 purging

Only for microemulsion

(10 times with full

release of pressure)

Motor Speed 250 rpm

Pressure 20 psi

MMA I (g) 14.0400

MMA II (g) 42.1200

MMA total (g) 56.1600

Water (g) 348.9500

Main effects plot for conversion

Main effects plot for PDI

Main effects plot for Mn

Variations of experimental number-average molar mass and

polydispersity index (PDI) versus MMA conversions in single-step

emulsion (Expt. 4).

1.7

1.8

1.9

2

2.1

2.2

2.3

1000

6000

11000

16000

21000

35.0 40.0 45.0 50.0 55.0 60.0 65.0

PD

I

Mn

(g

/mo

l)

Conv (%)

Mn, th

Mn, GPC

PDI

Aggregation/Coagulation in Single-

Step emulsion.

Aggregation/Coagulation in Two-Step

emulsion.