Mlle. Ester SÁNCHEZ CASAS

SÁNCHEZ CASAS, Ester

1

MASTER THESIS

Chemical Engineer

Escola Tècnica Superior d’Enginyeria Industrial de Barcelona (ETSEIB) Universitat Politècnica de Catalunya (UPC)

by

Mlle. Ester SÁNCHEZ CASAS

MONITORING CONDUCTIVITY OF

EMULSION POLYMERIZATION

DIRECTED BY: Mme. Nida S. OTHMAN

M. Tim F. McKENNA

CPE Lyon

Laboratoire d’Automatique et de Génie des Procédés (LAGEP) Laboratoire de Chimie et Procédés de Polymérisation (LCPP)

43, Boulevard du 11 Novembre 1918 69616 Villeurbanne, cedex, France

23rd July 2012


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I. Abstract

In a polymerization reaction it is essential to control the physical properties of the particles which have

been obtained. These physical properties: molecular weight distribution, particle size, polymer

composition and morphology are fundamental parameters which determine the properties of the polymer.

In this project we attempt to develop on-line measurements controlling these parameters throughout the

polymerization: we are interested in studying the conductivity of the reaction medium during the

emulsion polymerization of styrene by radical (ascorbic acid, H2O2) and with the presence of surfactant

(SDS).

For this study we will rely on such measures as coupled calorimetry, dry mass and zetasizer (to

determinate the particle size), which will allow us to parameterize the conductivity measurement.

Initially, we will study the conductivity of a solution of surfactant without monomer to determine the

CMC (critical micelle concentration) of SDS at different temperatures (Series 0).

In the second part of the study we will investigate the reaction of styrene polymerization by adjusting

various parameters:

- The concentration of surfactant (Series 1)

- The introduction flow rate of the initiator (Series 2)

- The initial concentration of monomer (Series 3)

To reach a conclusion from these experiences: the conductivity can control precisely the presence of

micelles in the medium. These micelles are responsible for the control of physical parameters of the

resulting polymer. The conductivity should be calibrated according to the medium, the monomer and the

surfactant.

We will do additional tests to delve into the essence of this study, and understand the behavior of the

conductivity. We will also use a video probe to observe how could the particle size change size due to

different variations in the parameters.


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II. Summary

I. Abstract 3

II. Summary 4

III. Nomenclature 5

IV. Introduction 6

V. Theoretical part 7

1) Reaction et Kinetics 7

2) Monitoring the calorimetry polymerization 8

3) Monitoring the polymerization by dry mass 9

4) Emulsion polymerization 9

5) Formation of micelles and Conductivity 10

6) Formation of micelles and particle size 11

7) SDS on the surface of droplets 11

VI. Experimental part 13

1) Equipment 13

2) Experimental process 15

2.1 Series 0 15

2.2 Series 1,2 and 3 16

2.2 Video measurements 21

VII. Results and Discussion 22

1) Effect of temperature on the CMC (Series 0) 22

2) Effect of surfactant concentration (Series 1) 24

3) Effect of initiator’s flow rate introduction (Series 2) 30

4) Effect of monomer concentration (Series 3) 35

5) Experiment using APS as initiator 40

6) Experiments using KPS (Series A) 43

7) Experiments using VA-086 (Series B) 46

8) Video measurements 47

9) Different studies of conductivity 55

10) Miniemulsion (M01) 58

VIII. Conclusion 59

IX. Bibliographic references 60

X. Vocabulary 61


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III. Nomenclature

Symbol Name Units

[ ] Concentration mol.m-3

F Flow rate g/h

rpm Agitation Tour/min

G.P. Feed rate of the initiator %

M Mass kg

Cp Heat capacity J.kg-1.°C-1

U Heat transfer coefficient J.mol-1.°C-1

A Exchange surface m²

Q Amount of heat J

σ Conductivity S.m-1

λ Conductance S.m².mol-1

MW Molar mass g.mol-1

Np Number of particles

Dp Particle diameter nm

H Enthalpy J

T Temperature °C

v Speed mol.s-1

k Rate constant m3.s-1


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IV. Introduction

This study is focused on monitoring conductivity of a polymerization. Nowadays, polymers are very

important in the chemical industry, thus it is important to control the polymerization. One way to control

these reactions by monitoring conductivity coupled with calorimetry.

Actually, during an emulsion polymerization takes place the micelle formation which can be controlled

by conductivity. The essential particularity of these micelles is the particle.

Firstly, we will consider the CMC (critical micelle concentration) of our surfactant and we will try to

establish a relationship between micelle formation and the particle diameter obtained and the amount of

polymer formed.

The parameterization of the conductivity sensor will be using calorimetric measurements.

Calorimetry allows us to obtain Qr (the heat of reaction) and allows us to analyze the rate of

polymerization, the conversion throughout the reaction and the size of the particles.

We will do different measurements in order to study the polymerization, from samples taken at different

times during the reaction.

Additionally, we will do some studies in order to understand the meaning of the anomalies found during

the previous experiments.


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V. Theoretical part

1) Reaction et Kinetics

Reaction scheme:

HO

CH2

OH OH OH

OH

CH2HO

CH2HO CH2CH2HO

+

* Decomposition of the initiator (H2O2 / ASCA) of the polymerization:

H2O2 2 HO° 2 HO-M °

We suppose that ka is higher than kd and we have define the efficacy of initiator f

* Propagation:

HO-M ° + M HO –M-M°

* Termination: - By disproportionation

- Par coupling :

kd vd = = 2 f kd [H2O2]

va= ka [M][HO°]

ka

vp = ‐ = kp × [M] × [M°]

kp

vt = ‐ = 2 kt × [M °]²


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QR is the heat generated by the polymerization reaction

UA(TR-Tj) is the heat exchanged through the jacket

Qloss Qloss is the heat lost during the reaction through the device

• x is the conversion

• M0 is the initial mass of monomer

• MW represents the molecular weight of monomer

• n is the average number of radical particles

• Np is the number of particles per liter

• NA is Avogadro's number

• [M] p the concentration of monomer in the particles

We define the rate of polymerization: Rp = kp × [M]p n × = - =

2) Monitoring the calorimetry polymerization

Our reaction proceeds in a batch reactor (hall mock), the reaction temperature is controlled by a jacket.

We can write the energy balance as follows:

micpi × = Ficpi(Ti-TR) + QR – UA(TR-Tj) – Qloss

We neglect the other terms of energy due to agitation, and other

reactor components.

We can define the progress calorimetry as follows: X calorimetry (t)= , where Qmax is the

maximum heat maximum heat generated by the reaction. It is calculated using the following equation:

Q max = .


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3) Monitoring the polymerization by dry mass

We can define progress by measuring the dry mass from the equation above:

X masse=

Mlatex represents the mass of the solution

Msèche represents the mass remaining after drying

Mmonomère represents the monomer mass

4) Emulsion polymerization

An emulsion polymerization consists in an aqueous solution of water in a double-shell reactor. This water

is heated to a fixed temperature and is stirred at 300 rpm. We add to this water, a sufficient quantity of a

surfactant in order to form micelles. The surfactant is SDS in this study (see Figure 1). Once the mixture

has reached the set temperature the monomer (styrene) and the initiator (H2O2) were added into the

aqueous phase by the distilled water if necessary.

The surfactant stabilizes the monomer, and then there are formed micelles and monomer droplets in the

reaction medium because the monomer is less soluble in water than in the monomer (these droplets are

very big and will become reservoirs for monomer for the polymerization). The initiator is present in the

aqueous phase. Then we should allow the mixture to be homogenized for several minutes. Then we start

by running the reaction rate of ascorbic acid content in a syringe (the speed is also a parameter that we

will study). Ascorbic acid will allow the formation of radicals in the aqueous phase by reacting with the

monomer forming oligoradicals. The radicals or oligoradicals have statistically more probabilities to enter

into the micelles than in the monomer droplets and do not stay in solution. As their size increase, they

have less affinity with water.


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OSO3‐ Na+

Figure 1: Nucleation mechanisms during an emulsion polymerization.

The particle growth is then effected by transfer through the monomer from the aqueous phase drops. The

monomer in the aqueous phase is gradually consumed to increase the size of the micelles in oligoradicaux

precipitates or in solution. This implies the dissolution of monomer droplets which are thus progressively

consumed by displacement of equilibrium. Growth of primary particles can also occur by coagulation of

particles. Is obtained at the end of the reaction a polymer latex, i.e., a stable emulsion of polymer particles

whose size can range from 0.05 to 5 microns typically.

5) Formation of micelles and Conductivity

A surfactant is composed of a hydrophilic part which is soluble in water and a hydrophobic portion

(insoluble in water) soluble in polar solvents:

Figure 2: Schematic of surfactant: SDS

When the surfactant is introduced into the reactor (containing water) to a concentration below the

CMC: Assuming that the SDS is fully ionized, the solution contains a surfactant mixture


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composed of a hydrophilic surfactant. The ionic part is in the form of sodium ions and ion-

dodecyl C12H25SO4 .Cette ionic part is at the origin of the conductivity of the reaction mixture.

The conductivity of the solution then follows a linear law: σ = λNa+ x [Na+] + λSDS- x [SDS-]

(Q: we made several assumptions: There is no HO-ions in our environment because of H2O2 and ascorbic

acid has a negligible conductivity in the reaction medium)

If the surfactant concentration in the reactor is greater than the CMC, micelles are formed in the

reaction. The reason for their formation is because a surfactant molecule can reduce the solvation

energy by assembling the hydrocarbon chains in the form of a droplet. This droplet is excited

about the hydrophilic parts of surfactants, and is then soluble in water. The conductivity

decreases since then the concentration decreases surfactant free.

6) Formation of micelles and particle size

Surfactants are compounds that reduce surface tension between two media. When a medium is

saturated with surfactant molecules there will be formation of micelles. The CMC depends on

the geometry and functionality of the surfactant. And a surfactant with a longer chain form

micelles with a larger diameter and increase the CMC. When the micelle formation in a stirred

medium there is a thermodynamic equilibrium constant this is set up between fragmentation and

coalescence of the drops. This balance depends on various parameters including agitation but

also the surfactant selected. We can then "control" the size of the micelles which allows

controlling the particle diameter.

7) SDS on the surface of droplets

In order to calculate the SDS amount into droplets we have done these calculations:

º /

43

4

Units : σ (S.m‐1), λ (S. m2.mol‐1), [] (mol.m‐3)


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_ where: 40 80

_

_


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VI. Experimental part

1) Equipment

‐ ZETASIZER MALVERN: For measuring diameter particles.

Figure 3: Zetasizer de malvern.

‐ Metler LJ16: To calculate the dry mass.

Figure 4:Metler LJ16.


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‐ Conductivity probes:

Probe 1: Fisher bioblock scientific K10/PT1000/300mm :

Figure 5: Conductivity probe 1.

Probe 2: SKT21T-30

Probe 3: 856 Conductivity Module Metrohm :

Figure 6: Conductivity probe 3.

Ampliation:


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2) Experimental process

2.1 Series 0

1. Prepare the SDS + water and weigh.

2. Weight the water before putting into the reactor.

3. Put inside a syringe the solution of 1, and take out the bubbles inside of the surfactant; then don not

forget to weigh it full of solution.

4. Open the condenser (water entry).

5. Add water.

6. Connect the conductimeter between the PC & reactor.

7. Change Tsp in the computer (Tsp = 20/70/60/50... °C).

8. Cover all the entries of the reactor by caps.

9. Turn on ‘Bain’ and ‘Agitation’ buttons.

Figure 7: PC Supervision. Buttons.

10. Open the programme ‘Conductimeter2’ in ‘stages’ folder and create an empty excel file in our own

folder.

11. In the programme: Open the folder below and open the file already created.

12. When the Treactor is close to the estimated temperature:

- Press Start in the programme.

- Connect the syringe to the machine and turn on while timing by chronometer.


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(it goes slowly at the end, and the flow rate could change. Thus, stop the machine and the

chronometer).

13. Stop the programme.

14. Weigh the empty syringe.

2.2 Series 1,2 and 3

1. Check the aspiration (the hood).

2. Start the program (Reacteur) on the “PC supervision”.

3. Check the connection with the balance.

4. Clean the reactor with water 3 times.

5. Weight the necessary amount of surfactant on the precise balance.

6. Add water using the balance for more weight.

7. Add the conductivity probe and check connections.

Figure 8: Conductimeter.


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8. Open nitrogen valve (1 bar), check the flow rate after few minutes.

Figure 9: Nitrogen cylinder.

9. Insert into the reactor the surfactant + some water.

10. Open 2 valves of water (one for the condenser and another for cooling the bath), check the flow rates.

Stirrer is at 300 rpm.

Figure 10: Valves of water (condenser and bath cooler).

11. Press the green buttons of the bath and agitation.

12. Temperature set-point = 70°C; (Chauf_Inactif) with option auto.

13. Once temperature attains 70°C (30min) Add H2O2 and styrene. Keep it inside for 15 min till you

add the Ascorbic Acid.


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Figure 11: Hood to take the styrene from its bottle.

14. At PC supervision: put on the program (Supervision IFix). Execute (). Modify set-point again to

70°C. Do not close this window!

15. At PC distant:

Figure 12: PC Distant.

- Put on the program (Supervision pc distant). Execute ().

- write 70 in the file c:\donneeslabview\commandeT

- write 0 in the file c:\donneeslabview\commande_pompe

- « Autorisation commande » in « double enveloppe »

- « Autorisation commande » in « pompe manu » for semi-continuous exp.

- « Effacer le fichier de mesure »


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16. Start MATLAB:

- Directory C:\Documents and Settings\calorimetre\Bureau\stages\prog_matlab

- Open folder / Control-T-et-debit

17. Execute Conductimetre2 in stages.

Create an Excel file empty in the folder of conductivity and link it below.

18. Introduce Ascorbic Acid solution into the reactor by a syringe.

19. Put the azote (nitrogen) in the air of the reactor (or close it)

20. At PC distant:

- in Labview program clic on « marche enregistrement ».

- Execute Matlab program « control_T_et_debit”

- Clic on (Début commande temperatire)

21. Write the hour on the « PC distant »

22. Take a sample every 10 min.

Figure 13: Samples.

At the end:

23. PC distant : - Close the program conductimetre2.

- clic on FIN in matlab figure.

- write 20 in the file C:\DonneesLabview\commande_T.

- click on « arrêter l’enregistrement » in labview.

- copy the file « mesures » in c:\donneeslabview.


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24. Empty the reactor if T<40°C, latex goes into empty solvent bottles.

25. Put some water inside the reactor (about 100 g ) and through it into the latex bottle.

26. Clean the reactor with water once (through it into the sink).

27. Clean the reactor with THF (about 30min), put it back into its bottle.

28. Clean the reactor with water several times.

Figure 14: Reactor cleaned.

Data treatment :

29. Matlab / Open / Main-filtration in directory stage. Execute.

30. Excel / Open / stages/ prog_matlab / result filter-reduit / copier / collage / special / valeur adapt

length of all.

31. Copy data from the file of conductivity that we created before adapt length of all.


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2.2 Video measurements

We have assembled the necessary equipment to make a series of experiments with the video probe in

order to study the behaviour of the particles.

Figure 15: Equipment necessary for the studies with the video probe.


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VII. Results and Discussion

1) Effect of temperature on the CMC1 (Series 0)

During this series of measurements were studied the conductivity of distilled water with the continuous

addition of a SDS2 solution with known concentration. Here are all the data of this series:

Agitation 300 rpmWater reactor 800 g Syringe: Water 40 g SDS 5 g

Table 1: Data of series 0.

Figure 16 : Monitoring the conductivity of the mixture depending o the amount of SDS introduced.

We could notice that the experiment at 80 ºC is very different from the others because we have used a different probe.


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As we could see in the figure below, the CMC of SDS at 70 ºC is around 3 g SDS/l of water.

Figure 17: CMC of SDS at 70 ºC.

Table 2: CMC vs. T

Figure 18: Monitoring critical micelle concentration as a function of temperature.

Temperature (°C)

CMC (g/L)

22 2,4

40 2,4

50 2,67

70* 3

80 3,75

It is observed that the CMC increases with temperature. The more temperature, the more solubility of

SDS. In order to form micelles at higher temperatures more surfactant should be added.


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2) Effect of surfactant concentration (Series 1) During this series of measurements has been studied the effect of surfactant concentration. Here are all

the data of this series:

Styrene 6 % Water 800 g

H2O2 3 g/l

Agitation 300 rpm

Temperature 70 º C Solution of ascorbic acid. Seringe:

Asc Acid 0,5 g Water 10 g G.P.3 22 %

Flowrate 0,45 g/h


- Temperature & Heat:

We note that when we add more surfactant concentration, the heat generated by the reaction is higher.

Actually, it is because adding more surfactant, the number of micelles increases and therefore, the number

of particles.

Figure 19: Medium temperature of the reaction vs. time.

69

69,5

70

70,5

71

71,5

72

72,5

73

0 10 20 30 40 50 60

(°C

)

Time (min)

Temperature[SDS]=3.4g/L[SDS]=3.4g/L*[SDS]=3.6g/L[SDS]=3.8g/L[SDS]=4g/L[SDS]=4.2g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L

[SDS] (g/l)

SERIE 1 ES7 3,4 ES8 3,1 ES9 3,8 ES10 4,2 ES11 3,6 ES19 ES9 3,8 ES18 4,2 ES20 5 ES21 6 ES22 ES10 4,2 ES30 ES7 3,4 ES31 4 ES32 5,5


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Figure 20: Heat produced by the reaction vs. time.

- Conversion:

Conversion was plotted versus time in two different ways. The first way, is the thermal conversion from

the heat reaction (Figure 21) and the second way, is from the dry mass of samples which has been taken

experimentally during the reaction (Figure 212).

The turning point (the half of the conversion) corresponds to the maximum peak temperature, which is

due to the maximum heat generated by the reaction. After this phase, the reaction rate decreases because

there is less of monomer present in the reactor. There is no relation between the fact of increasing the

concentration of surfactant and the conversion. The conversion depends on many things but the most

important sources of error are:

a. Variable thermal transmittance coefficient; U (W/m2K), which depends on the heat loss

in the reactor (Qloss).

b. The beginning of the reaction; because sometimes the reaction starts late because of the

presence of bubbles in the syringe.

The technique for measuring the conversion using the dry mass can be distorted by different sources of

error:

a. Take a sample unrepresentative from the mixture in the reactor.

b. Machine error of the dry mass.

c. By not agitating sufficient the sample before the measurement.

0

10

20

30

40

50

60

0 10 20 30 40 50 60

(W)

Time (min)

Heat produced by the reaction[SDS]=3.4g/L[SDS]=3.4g/L*[SDS]=3.6g/L[SDS]=3.8g/L[SDS]=4g/L[SDS]=4.2g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L


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Figure 21:Plot of conversion (measured by calorimetry) vs. time.

Figure 22: Plot of conversion (measured by dry mass) vs. time.

- Mean diameter & Particle number: Theoretically, by increasing the amount of SDS in the reactor, the number of miscelles should increase

and also the polymer particles formed into the miscelles sould be smaller. We observe a decrease in the

particle mean diameter and an increase in the number of particles (Figures 23 & 24).

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60

(%)

Time (min)

Conversion

[SDS]=3.4g/L[SDS]=3.4g/L*[SDS]=3.6g/L[SDS]=3.8g/L[SDS]=4g/L[SDS]=4.2g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40 45 50

(%)

Time (min)

Conversion

[SDS]=3.4g/L[SDS]=3.4g/L[SDS]=3.6g/L[SDS]=3.8g/L[SDS]=4g/L[SDS]=4.2g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L


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Figure 23: Average particle diameter vs. time.

Figure 24: Number of particles vs. time.

In our experiments we could notice that the heat of the reaction could be related to the number of particles

(See experiences with [SDS] = 6 g/l and 5,5 g/l in figures 20 & 26). The more particles created, the more

heat generated because there are more reactions.

10

15

20

25

30

35

40

45

50

55

0 10 20 30 40 50

(nm

)

Time (min)

Mean diameter

[SDS]=3.4g/L*[SDS]=3.8g/L[SDS]=4g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L

0

3E+17

6E+17

9E+17

1,2E+18

1,5E+18

0 10 20 30 40 50Time (min)

Particle number[SDS]=4.2g/L

[SDS]=4g/L

[SDS]=5.5g/L

[SDS]=6g/L


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As we could see in the figures below, the mean diameter decreases as a function of SDS concentration, and the particle number increases. Furthermore, it is observed that along the reaction more particles with a smaller diameter are formed.

Figure 25: Average diameter of particles as a function of conversion.

Figure 26: Number of particles as a function of conversion.

0

10

20

30

40

50

60

0 20 40 60 80 100

(nm

)

Conversion (%)

Mean diameter

[SDS]=3.8g/L

[SDS]=4g/L

[SDS]=5g/L

[SDS]=6g/L

[SDS]=5.5g/L

0

3E+17

6E+17

9E+17

1,2E+18

0 20 40 60 80 100Conversion (%)

Particle number

[SDS]=3.8g/L

[SDS]=4g/L

[SDS]=5.5g/L

[SDS]=6g/L


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- Conductivity :

We could see that the conductivity of the mixture at the beginning of the reaction is lower than expected

conductivity (Series 0, Table 4 & Figure 17). We have introduced a higher SDS concentration than the

CMC. The difference can be explained by the presence of the monomer (non-conductive carbon chain

part), which is present in the reactor in droplets that reduces the conductivity and may also affect the

measurement of the conductivity probe. We had used 2 different probes during the project, and we have

noticed that the probes are affected adversely by the monomer which fixes fast on the surface of the

plaques. The more experiments were performed, more erroneous results were obtained.

Figure 27: Monitoring the conductivity of the reaction function of time.

[SDS] (g/L)

conductivity (µS/cm)

3,4 441 3,6 454 3,8 466 4,2 487 4 476 5 521

Table 4: Conductivity vs. SDS concentration at 70 ºC. Series 0.

0

100

200

300

400

500

600

0 10 20 30 40 50 60

(µs/

cm)

Reaction time (min)

Conductivity[SDS]=3.4g/L[SDS]=3.4g/L*[SDS]=3.6g/L[SDS]=3.8g/L[SDS]=4.2g/L[SDS]=4g/L[SDS]=5g/L[SDS]=5.5g/L[SDS]=6g/L


30

3) Effect of initiator’s flow rate introduction (Series 2)

During this series of measurements has been studied the effect of the flow rate of the initiator (ascorbic

acid) has been studied. We have introduced by a syringe, a solution of ascorbic acid, changing the flow

rate of this syringe. You can see below all the data obtained of this series:

Styrene 6 % SDS 3,4 g/l

Water 800 g

H2O2 3 g/l

Agitation 300 rpm


Asc Acid 0,2 g Water 10 g



We can observe that the flow rate of Ascorbic Acid is important. If the flow rate is slower, the reaction

starts later. There is not much difference between the amounts of the heat produced by the reaction as a

function of ascorbic acid’s flow rate, but we can see that the reaction is faster for higher flow rates.

Figure 28: Monitoring of temperature vs. time.

67

68

69

70

71

72

73

0 20 40 60 80 100 120

(°C

)

Time (min)

Temperature

F AscA = 0.076 g/h

F AscA = 0.129 g/h

F AscA = 0.173 g/h

Flowrate Asc Acid (g/h)

SERIE 2 ES12 0,136 ES13 0,143 ES14 0,076 ES25 0,055 ES27 ES12 0,136 ES33 0,129 ES34 0,173 ES35 0,286 ES36 0,284 ES37 0,087


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Figure 29: Monitoring of heat production vs. time.

- Conversion:

We observe the same that in the case of the section of Temperature & Heat; the conversion starts before

with a higher flow rate. However, it does not mean that it should achieve the highest conversion. There is

no relation between these factors.

Figure 30: Monitoring of the conversion (measured by calorimetry) vs. time.

0

5

10

15

20

25

30

35

40

0 20 40 60 80 100 120

(W)

Time (min)

Heat produced by the reactionF AscA = 0.076 g/h

F AscA = 0.129 g/h

F AscA = 0.173 g/h

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100 120

(%)

Time (min)

Conversion

F AscA = 0.076 g/h

F AscA = 0.129 g/h

F AscA = 0.173 g/h


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Figure 31: Monitoring of the conversion (measured by dry mass) vs. time.

- Mean diameter & Particle number:

We obtained a mean diameter particle of: 30-55 nm. We could also appreciate that with a lower flow rate,

we are able to obtain particles with a larger diameter. In the experiments of flow rates from 0,129-0,286

g/h it is not possible to appreciate any relation with the initiator’s flow rate.

Figure 32: Average diameter of particles vs. time.

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

(%)

Time (min)

Conversion

F AscA = 0.076 g/h

F AscA = 0.129 g/h

F AscA = 0.173 g/h

0

10

20

30

40

50

60

0 20 40 60 80 100

(nm

)

Time (min)

Diameter

F AscA = 0.076 g/h

F AscA= 0.086 g/h

F AscA = 0.129 g/h

F AscA = 0.136 g/h

F AscA = 0.143 g/h

F AscA = 0.173 g/h

F AscA = 0.284 g/h

F AscA = 0.286 g/h


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We could see that the particle number increases when the initiator’s flow rate is higher:


We also plotted the mean diameter and the particle number with the conversion of the reaction.

Unfortunately, we realized that there is not any direct relation.

- Conductivity :

We could only observe that the conductivity decreases before (the reaction starts) when the initiator’s

flow rate is higher. However, we could not notice any relation between the other experiments, and we

have also a lot of problems in this series with the conductivity probe. As decreasing near 0, we had

noticed that the probe was broken.

Besides, the reaction time (decreasing part) is approximately the same in both cases. We cannot

appreciate any difference.

According to the Series 0, both experiments should start at 441 µS/cm (3,4 g/l SDS).

0

2E+17

4E+17

6E+17

8E+17

1E+18

1,2E+18

0 20 40 60 80 100Time (min)

Particle number F AscA= 0.086 g/h

F AscA = 0.129 g/h

F AscA = 0.143 g/h

F AscA = 0.284 g/h


34

Figure 34: Monitoring the conductivity of the medium vs. time.

We also plotted the conductivity with the conversion of the reaction. Unfortunately, we realized that there

is no any direct relation.

0

100

200

300

400

500

600

0 10 20 30 40 50 60 70 80 90 100

(µs/

cm)

Reaction time (min)

Conductivity

F AscA = 0.076 g/h

F AscA = 0.143 g/h

START


35

4) Effect of monomer concentration (Series 3)

During this series of measurements has been studied the effect of monomer concentration. Here are all the

data of this series:

SDS 4,2 g/l Water 800 g

H2O2 3 g/l

Agitation 300 rpm


Asc Acid 0,5 g Water 10 g G.P. 22 %

Flowrate 0,45 g/h Table 6: Data of series 3.


The more monomer addition, the reaction reaches a higher temperature, and the heat of reaction is higher

too. We could see that the curve of Styrene at 7% starts very late, the main reason could be that there

probably were bubbles into the syringe and did not work well at the beginning. In fact, we had had a lot of

problems with the flow rate of ascorbic acid, which could not find any logical relation between the

obtained results.

Figure 35: Monitoring of temperature vs. time.

67

68

69

70

71

72

73

74

75

76

0 10 20 30 40 50 60

(°C

)

Time (min)

Temperature

Sty = 6 %Sty = 7 %Sty = 8 %Sty = 11 %

Styrene (%)

SERIE 3 ES10 6 ES15 8 ES16 9,6 ES17 11 ES38 7 ES39 9


36

Figure 36: Monitoring of heat production vs. time.

- Conversion:

We can see that there is no logical relation between the conversion and the concentration of monomer

introduced into the reactor, if we measure by dry mass. Probably, this is because of the number of error

sources already explained in series 1.

Figure 37: Plot of conversion (measured by calorimetry) vs. time.

0

10

20

30

40

50

60

0 10 20 30 40 50 60

(W)

Time (min)

Heat produced by the reaction

Sty = 6 %

Sty = 7 %

Sty = 8 %

Sty = 11 %

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60

(%)

Time (min)

Conversion

Sty = 6 %Sty = 7 %Sty = 8 %Sty = 11 %


37

Figure 38: Plot of conversion (measured by dry mass) vs. time.

- Mean diameter & Particle number:

We could notice that the more monomer added the more diameter particles. Nevertheless, we cannot say

the same for the particle number. It seems to be similar in all the experiments, no difference between all

of them.

Figure 39: Average diameter of particles vs. time.

0

20

40

60

80

100

120

0 10 20 30 40 50 60

(%)

Time (min)

ConversionSty = 6 %Sty = 7 %Sty = 8 %Sty = 9.6 %Sty = 11 %Sty = 11 %*

0

10

20

30

40

50

60

0 20 40 60

(nm

)

Time (min)

Diameter

Sty = 6 %

Sty = 7 %

Sty = 11%


38


It is observed that the diameter particles increases as a function of conversion, and the particle number

does not change a lot during the reaction.

Figure 41: Average diameter of particles as a function of conversion.

0

5E+17

1E+18

1,5E+18

2E+18

2,5E+18

0 20 40 60

Time (min)

Particle number

Sty = 6 %

Sty = 7 %

Sty = 11%

Sty = 11 %*

0

10

20

30

40

50

60

0 20 40 60 80 100 120

(nm

)

Conversion (%)

Diameter

Sty = 6 %

Sty = 7 %

Sty = 11%

Sty = 11 %*


39

Figure 42: Number of particles as a function of conversion.

- Conductivity :

Theoretically, if the monomer added is higher, the reaction should start before, but according to the

experiments done, we are not able to confirm that. As increasing the quantity of monomer, we increase

the amount of non ionic substances in the reactor, and this affects directly the conductivity which starts at

a lower value. Some of the ionic substances are diluted.

It is very difficult to validate the last two experiments of this series (Sty at 7% and at 11%) because they

have been made with a limited number of samples because the new probe has been broken by the

agitation of the reactor.

Figure 43: Monitoring the conductivity of the medium vs. time.

0

5E+17

1E+18

1,5E+18

2E+18

2,5E+18

0 20 40 60 80 100

Conversion (%)

Particle number

Sty = 6 %

Sty = 7%

Sty = 11%

Sty = 11 %*

0

100

200

300

400

500

600

0 10 20 30 40 50 60

(µs/

cm)

Reaction time (min)

ConductivitySty = 6 %Sty = 7 %Sty = 8 %Sty = 11 %*


40

5) Experiment using APS4 as initiator

At the beginning of the project we realized an experiment using APS in order to get in use with the

equipment and the programs, and take some decisions from the results for future experiments:


Water 800 g

APS 3 g/l

Agitation 400 rpm

Temperature 70 º C Table 7: Data of APS experiment.

- Temperature & Heat :

We could observe the gel effect, which is a dangerous reaction behaviour that can occur in free radical

polymerization systems. It is due to the localized increases in viscosity of the polymerizin system that

slow termination reactions. The removal reaction obstacles therefore causes a rapid increase in the overall

rate of reaction, leading to possible reaction runaway and altering the characteristics of the polymers

produced. The gel effect can also occur when the temperature of the reaction is kept constant. (RAVVE,

2000)

Figure 44: Temperature & Heat vs. time.

60

62

64

66

68

70

72

74

0 50 100

(°C

)

Time (min)

Temperature

TréacteurTj inTj outset-point

0

10

20

30

40

50

60

0 20 40 60 80 100

(W)

Time (min)



41

- Conversion & Solids content:

We could see the conversion obtained by calorimetry. We also plotted the conversion obtained by dry

mass; however, the results differ greatly from reality.

In order to prevent coagulation for future experiments, we decided that the limit of solid content should

be at 10 %.

Figure 45: Conversion & Solids content vs. time.

- Mean diameter & particle number :

We obtained a diameter particle around 90 nm for all the samples.

The number of particles increases during the reaction.

Figure 46: Mean particle diameter & Number of particles.

0,00

20,00

40,00

60,00

80,00

100,00

0 20 40 60 80 100

(%)

Time (min)

Conversion

0

2

4

6

8

10

12

14

0 20 40 60 80 100

(%)

Time (min)

Solids content

0

20

40

60

80

100

0 20 40 60 80 100

(nm

)

Time (min)

Mean particles diameter

0

5E+16

1E+17

1,5E+17

2E+17

2,5E+17

3E+17

3,5E+17

0 20 40 60 80 100Time (min)

Number of particles


42

- Conductivity :

We notice an important decrease in conductivity when adding monomer.

We could see that the addition of ammonium persulfate (APS) increases significantly the conductivity.

This is because APS decomposes by hemolytic scission due to thermal. The degradation of one mole of

the initial reagent (NH4)2S2O8, provides two moles of free radicals, each carrying one negative charge at

their extremity: SO•4

-, NH4

+. (BOUTTI, 2002)

Figure 47: Conductivity vs. time.

We have observed a lot of coagulation around the stirrer. After this experiment (stirring at 400 rpm), we

decided to use 300 rpm for future experiments, in order to reduce coagulation.

0

200

400

600

800

1000

1200

-30 -20 -10 0 10 20 30

(µs)

Reaction time (min)

Conductivity conductivity

monmer addition

APS addition


43

6) Experiments using KPS5 (Series A)

We have done this simple series in order to realize that the conductivity probe was definitely broken. It is

easy to see it from this series because there were a lot of previous studies with this initiator. In fact, we

took the same conclusions from Series 2 with ascorbic acid as initiator.


Water 800 g

Agitation 300 rpm

Temperature 70 º C

‐ Temperature & Heat :

When increasing the KPS concentration, the reaction starts before.

Figure 48: Temperature & Heat produced by the reaction vs. time.

60

62

64

66

68

70

72

74

0 10 20 30 40

(°C

)

Time (min)

Temperature

[KPS]=2g/l

[KPS]=3g/l

0

10

20

30

40

50

0 10 20 30 40

(W)

Time (min)


[KPS]=2g/l

[KPS]=3g/l

[KPS] (g/l)

SERIES A ES40 2 ES41 3

Table 8: Data of series A.


44

‐ Conversion & Solids content :

We could see that the conversion works well for this series. As increasing the KPS concentration, the

reaction starts before.

Figure 49: Conversion & Solids content vs. time.

‐ Mean diameter & particle number :

We notice that the more KPS concentration, smaller diameter particles and higher number of particles

generated during the polymerization.

Figure 50: Mean particles diameter & Number of particles vs. time.

0102030405060708090

100

0 10 20 30 40

(%)

Time (min)

Conversion

[KPS]=2g/l[KPS]=2g/l[KPS]=3g/l[KPS]=2g/l 0,0

1,0

2,0

3,0

4,0

5,0

6,0

0 10 20 30 40

(%)

Time (min)

Solids content

[KPS]=2g/l

[KPS]=3g/l

0

10

20

30

40

50

60

0 10 20 30 40

(nm

)

Time (min)

Mean particles diameter

[KPS]=2g/l

[KPS]=3g/l

0

2E+17

4E+17

6E+17

8E+17

1E+18

1,2E+18

0 10 20 30 40Time (min)

Number of particles

[KPS]=2g/l

[KPS]=3g/l


45

Figure 51: Diameter & number of particles vs. conversion.

‐ Conductivity :

Unfortunately, we realized that the conductivity probe 2 was broken after doing this experiment. We had

to stop this study of conductivity because we could not take any real measurement of conductivity.

0

10

20

30

40

50

60

0 20 40 60 80

Dia

met

er (

nm)

Conversion (%)

Diameter vs. Conversion

[KPS]=2g/l

[KPS]=3g/l0

2E+17

4E+17

6E+17

8E+17

1E+18

1,2E+18

0 20 40 60 80

Num

ber

of p

arti

cles

Conversion (%)

Number of particles vs. Conversion

[KPS]=2g/l

[KPS]=3g/l


46

7) Experiments using VA-0866 (Series B)

The advantage of using VA-086 is a nonionic initiator that will not affect the conductivity.

VA-086 3 g/l

SDS 4,5 g/l

Water 800 g

Agitation 300 rpm

Temperature 70 º C

‐ Temperature & conductivity :

At the beginning we see an important decrease of conductivity at nucleation time (as in APS experiment).

We notice that the conductivity of water, SDS and monomer droplets is higher in ES4 than in ES5, this

could be because there are more droplets.

In both experiments we could appreciate that there is not an important effect on conductivity when the

reaction should starts. We did not observe any decrease in conductivity, probably there is no coagulation

since diluted, but the increase of ES4 seems to be similar to APS experiment. This increasing part may be

due to the consumption of monomer droplets or some existing coagulation.


0

100

200

300

400

500

600

700

800

900

1000

-20 30 80 130 180 230

(µs/

cm)

Reaction time (min)

Conductivity (µs) Conductivity ES4

Conductivity ES5

Initiator addition

start ES4

start ES5

Styrene (%)

SERIES B ES4 6 ES5 11

Table 9: Data of series B.


47

Figure 53: Conductivity & Treactor vs. time.

After this series of experiments, we made an important decision. According to the results, we concluded

that the VA-086 which was bought in 1999 was probably too old and does not work well for

polymerization. We decided to use another non ionic initiator: hydrogen peroxide, because it was easily at

our disposal.

8) Video measurements

8.1 Effect of stirring rate

We had done two different tests changing the stirring in order to know how could affect the particle size

and the distribution. According to this experiment we will decide at which stirring rate we will work for

future experiments. In the pictures below of two different tests, we could notice that the droplets are

smaller when increasing the stirring rate. We can observe at the highest stirring rate for both tests, that

there are some big particles, but we should not confuse with this, because these are the some bubbles

which had been created because of the high agitation.

Figure 54: Stirring at 200 & 520 rpm (TESTS "S").

69

69,5

70

70,5

71

71,5

0

100

200

300

400

500

600

0 30 60 90 120

T(°

C)

(µs/

cm)

Reaction time (min)

Conductivity ES4Treactor ES4

69,5

70

70,5

71

71,5

0

100

200

300

400

500

0 50 100

(°C

)

(µs/

cm)

Reaction time (min)

Conductivity ES5

Treactor ES5


48

Figure 55: Stirring at 663 & 873 rpm (TESTS "S").

Figure 56: Stirring at 200 & 300 rpm (TESTS TG1).

Figure 57: Stirring at 400 & 500 rpm (TESTS TG1).


49

We could observe that the surface area of droplets is very small (in TG and “S”). According to the results

of [SDS] into water and the conductivity, we can consider that do not change because of the stirring rate.

They are almost constant when changing the agitation rate. This means that we do not need to take into

account droplet size during future conductivity calibrations.

Figure 58: Effect of stirring in diameter, conductivity, [SDS] into water and surface area.

8.2 Effect of monomer concentration

We realized that the monomer composition has a minor effect on the droplet size; however, it has an

important effect on the number of droplets. As increasing the monomer concentration we obtained:

‐ An increasing of Ndroplets.

‐ An increasing of Sdroplets.

‐ A slightly decreasing of [SDS] into water.

0

10

20

30

40

50

60

70

80

0 500 1000

Dia

met

er (

µm

)

Stirring rate (rpm)

Effect of stirring

S

TG1

0

100

200

300

400

500

600

0 500 1000C

ond

uct

ivit

y (µ

S/c

m)

Stirring rate (rpm)

Effect of stirring

0,98

1,00

1,02

1,04

1,06

1,08

1,10

1,12

1,14

0 500 1000

[SD

S]

into

wat

er (

g)

Stirring rate (rpm)

Effect of stirring

0,0

0,2

0,4

0,6

0,8

1,0

1,2

0 500 1000

Rat

io o

f su

rfac

e a

rea

Stirring rate (rpm)

Effect of stirring


50

Besides, we concluded that is not necessary to take into account the monomer concentration (Styrene)

during conductivity calibrations because its effect is almost negligible.

Figure 59: Effect of [monomer] on conductivity, number of droplets, ratio of surface area and diameter particles.

Figure 60: Effect of [monomer] on conductivity vs. diameter

0

100

200

300

400

500

600

0 2 4 6 8 10

Con

du

ctiv

ity

(µS

/cm

)

monomer (%)

Effect of monomer composition

0,0E+00

1,0E+08

2,0E+08

3,0E+08

4,0E+08

0 5 10

Nu

mb

er o

f d

rop

lets

monomer (%)


0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0 5 10

Rat

io o

f sr

ufa

ce a

rea

monomer (%)


0

10

20

30

40

50

60

0 2 4 6 8 10

Dia

met

er (

µm

)

monomer (%)


0

100

200

300

400

500

600

46 48 50 52 54

Con

du

ctiv

ity

(µS

/cm

)

diameter (µm)



51

Figure 61: Volume droplet size distribution vs. diameter.

Figure 62: Number droplet size distribution vs. diameter.

0

1

2

3

4

5

6

7

8

9

10

0 50 100 150 200

(%)

Diameter (µm)

Volume droplet size distribution

[St]=12.6%

[St]=18.2%

[St]=21.1%

0

1

2

3

4

5

6

0 50 100 150 200

(%)

Diameter (µm)

Number droplet size distribution

[St]=12.6%

[St]=18.2%

[St]=21.1%


52

8.2.1 Styrene into water (ES44)

We tried to study if the concentration of styrene could affect directly to the conductivity. Here there are

the values of this experiment:

Mass syringe full 70,9 g Mass syringe empty 54 g

G.P. 26 %

Agitation 400 rpm

Introduction time 26,50 min Flow rate 38,26 g/h

Temperature Tamb º C Table 10: Data of ES44.

This experiment could explain many things that we have not understand till now for series 1, 2 and 3.

In fact, we could observe that increasing addition of monomer composition makes decrease the

conductivity. Thus, this effect explains why we had always obtained an initial value of conductivity

below the expecting value (from the series 0). To sum up, the addition of monomer in a

polymerization makes decrease the conductivity.


y = -0,9614x + 324,69R² = 0,9972

295

300

305

310

315

320

325

330

0,00 5,00 10,00 15,00 20,00 25,00 30,00

(µs)

Time (min)

Conductivity


53

Figure 64: Conductivity vs. diameter & diameter vs. monomer composition.

Figure 65: Conductivity & ratio of surface area vs. monomer composition.

We have calculated the ratio of surface area as we explained before in the theoretical part, section 7.

0

50

100

150

200

250

300

350

0 20 40 60 80

Con

du

ctiv

ity

(µS

/cm

)

diameter (µm)

Monomer + water

0

10

20

30

40

50

60

70

0 2 4 6

Dia

met

er (

µm

)

monomer (%)

Monomer + water

0

50

100

150

200

250

300

350

0 2 4 6

Con

du

ctiv

ity

(µS

/cm

)

monomer (%)

Monomer + water

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0 2 4 6

Rat

io o

f sr

ufa

ce a

rea

monomer (%)

Monomer + water


54

8.3 Effect of [SDS]

In the figure of diameter vs. SDS concentration, we could notice that [SDS] has a minor effect on the

droplet size. This means that [SDS] onto droplets is almost constant. In the second figure of conductivity

vs. [SDS], we could see that the measured conductivity is similar to the conductivity into water;

increasing linearly.

Figure 66: Effect of [SDS] on diameter and conductivity.

Figure 67: Effect of [SDS] on conductivity vs. diameter.

0

10

20

30

40

50

60

0 10 20 30

Dia

met

er (

µm

)

[SDS] (g/L)

Effect of [SDS]

0

200

400

600

800

1000

1200

1400

0 10 20 30C

ond

uct

ivit

y (µ

S/c

m)

[SDS] (g/L)

Effect of [SDS]

0

200

400

600

800

1000

1200

1400

44 46 48 50 52

Con

du

ctiv

ity

(µS

/cm

)

diameter (µm)

Effect of [SDS]


55

9) Different studies of conductivity

9.1 Styrene into water + SDS (ES42)

We studied if there styrene composition could affect directly a solution of water and SDS. Here there are

the values of this experiment:

Mass syringe full 56,4 g Mass syringe empty 40,3 g

G.P. 26 %

Agitation 400 rpm

Introduction time 29 min Flow rate 33,31 g/h

Temperature Tamb º C Table 11: Data of ES42.

By adding monomer, we could observe 2 effects:

1. The dillution of ionic species.

2. The capture of SDS on monomer droplets.

At the beginning we observe the same behaviour that in ES44; a decreasing because of the monomer

addition, but after that, we notice that the conductivity is till slightly decreasing. This explains why we

had obtained a low value of conductivity at the beginning of all our series (1, 2 and 3).


460

480

500

520

540

560

580

0 10 20 30

(µs)

Time (min)

Conductivity


56

According to the particle size, we execute a program which determines the distribution of the particle size

taking pictures from all the videos that the video probe had created. We could see that firstly, the particles

are bigger, and at the end of the experiments they became a bit smaller.

Figure 69: Distribution of number of particles vs. diameter particle from ES42.

Figure 70: Effect of monomer introduction.

0 50 100 150 200 250 300 350 4000

20

40

60

80

100

120

140

Taille (µm)

Nom

bre

ES42-01

0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500

3000

Taille (µm)N

ombr

e

ES42-07

0

100

200

300

400

500

600

700

0 20 40 60 80

Con

du

ctiv

ity

(µS

/cm

)

diameter (µm)

Effect of monomer intro.

0

10

20

30

40

50

60

70

0 2 4 6

Dia

met

er (

µm

)

monomer (%)


0

100

200

300

400

500

600

700

0 2 4 6

Con

du

ctiv

ity

(µS

/cm

)

monomer (%)


0,0

0,2

0,4

0,6

0,8

1,0

0 2 4 6

Rat

io o

f sr

ufa

ce a

rea

monomer (%)



57

We have already explained how to calculate the ratio of surface area in theoretical part, section 7.

9.2 KPS into water (ES45)

We notice that the addition of initiator KPS, as being an ionic initiator makes increase the conductivity of

the mixture. It is very helpful to understand the series A at the beginning of the experiment.

Unfortunately, we did not obtain real values of conductivity for series A.

Seringe Mass (g) Water 40,08 GP 99% KPS 3,1 T 70 °C

Flowrate 2,8071 g/min Introduction t 14 min Introduced m 39,3 g

Water reactor 807,3 g Table 12: Data of experiment ES45.

Figure 71: Conductivity vs. KPS introduced.

y = 3E+06x + 79,412R² = 0,9976

0

500

1000

1500

2000

2500

3000

0,E+00 2,E-04 4,E-04 6,E-04 8,E-04 1,E-03

Con

duct

ivit

y (µ

S/c

m)

[KPS] (g/L)


58

10) Miniemulsion7 (M01)

We started to understand how a miniemulsion works in order to find the effect of droplet size on

conductivity, as we have already done in video experiments. Here we have the data of this experiment:

Water 800 g SDS 3,4 g/l

Styrene 4 %

n-hexadecane 2 g Table 13: Data of M01.

As we can see, by adding the monomer, the conductivity decreases a little. Besides, when we increase the

stirring rate, the conductivity decreases significativily till the reaction achieves stability.


We could not increase more the agitation because the latex was almost overflowing from the container.

500

700

900

1100

1300

1500

0 10 20 30 40 50

Con

duct

ivit

y (µ

S/c

m)

Time (min)

Conductivity Miniemulsion500 rpmmonomer+n-hexadec."1000 rpm2000 rpm


59

VIII. Conclusion

The monitoring of emulsion polymerization is complex and depends on many parameters.

The fact of using an anionic surfactant such as SDS, allowed us to determine the CMC of SDS. When the

micelle formation starts, we can control the diameter and particle number. This measurement of

conductivity depends mainly on the amount of monomer added and the convenience to be absorbed into

water reactor.

We have realized the difficulties of using a conductivity probe. The metal plates were very fragile. In fact,

we had two different probes at our disposal; one of them had the plates exposed directly to the solution,

this made them get dirty quickly because of the different phases in the reactor and thus we have obtained

incorrect conductivity measurements. The new conductivity probe seemed better at first glance, because

the plates were covered with glass and fixed between them. However, the glass which was fixed between

them was broken too. Thus, the plates were vibrating because of the agitation of the reactor at each

experiment, and we obtained unreal and distorted conductivity measurements.

In addition to this problem, there is the issue of the necessary calibration of the probe before each

experiment, which is not possible to be made in a continuous process such as in the industry. On an

industrial scale, monitoring conductivity seems to be difficult to implement for monitoring emulsion

polymerization. However, it is conceivable to be used in order to determine exact the end of the reaction.


60

IX. Bibliographic references

ASUA, José M. (2007). Polymer reaction engineering. Institute of polymer materials (polymath). The

University of the Basque Country (Spain). Blackwell Publishing Ltd.

BOUTTI, S. (2002). High solid content latexes. Villeurbanne: Ph.D Thesis. Universite Claude Bernard

Lyon I. Laboratoire de chimie et procédés de polymérisation (LCPP).

FARSHCHI TABRIZI, Farshad (2004). On-line monitoring of emulsion polymerization by conductimetry

and calorimetry. Villeurbanne: Ph.D Thesis. Universite Claude Bernard Lyon I. Laboratoire

d'Automatique et de Génie des procédés (LAGEP) et Laboratoire de Chimie et Procédés de

Polymérisation (LCPP).

Mason TG, W. J. (2006). Nanoemulsions: formation, structure, and physical properties. Journal of

Physics: Condensed Matter.

RAVVE, A. (2000). Principles of polymer chemistry. New York: Kluwer Academic / Plenum Publishers.

Second Edition.

SH'EIBAT OTHMAN, Nida. (2000). Advanced strategies for composition control in semi-continuous

emulsion polymerization. Villeurbanne: PhD Thesis. Universite Claude Bernard Lyon I. Laboratoire de

Chimie et procédés de polymérisation CNRS - CPE.

http://www.msc.univ-paris-diderot.fr/~henon/III-micelles.pdf

http://hal.archives-ouvertes.fr/docs/00/13/58/98/PDF/These_Stephane_Arditty.pdf

http://ethesis.inp-toulouse.fr/archive/00000737/01/rondel.pdf


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X. Vocabulary

1 CMC (Critical Micelle Concentration): concentration of surfactants above which micelles form and

almost all additional surfactants added to the system go to micelles. Before reaching the CMC, the surface

tension changes strongly with the concentration of the surfactant. After reaching the CMC, the surface

tension remains relatively constant or changes with a lower slope. The value of the CMC for a given

dispersant in a given medium depends on temperature, pressure, and (sometimes strongly) on the

presence and concentration of other surface active substances and electrolytes. Micelles only form

above critical micelle temperature.

2SDS: Sodium dodecyl sulfate

3 G.P.: Graduation Pump

4 APS: Ammonium Persulfate.

5 KPS: Potassium persulfate.

6 VA-086: Is a trade product name for a non ionic initiator. See the information attached provided from

the supplier:


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7 Miniemulsion: (also known as nanoemulsion) is a special case of emulsion. A miniemulsion is obtained

by shearing a mixture comprising two immiscible liquid phases (for example, oil and water), one or

more surfactants and, possibly, one or more co-surfactants (typical examples are hexadecane or cetyl

alcohol). Stable droplets are then obtained, which have typically a size between 50 and 500 nm.

Miniemulsion-based processes are, therefore, particularly adapted for the generation of nanomaterials.

There is a fundamental difference between traditional emulsion polymerisation and a miniemulsion

polymerization. Particle formation in the former is a mixture of micellar and homogenous nucleation;

particles formed via miniemulsion however are mainly formed by droplet nucleation. (MASON TG,

2006)