Automatic, Continuous Online Monitoring of Polymerization Reactions  (ACOMP)

    We recently developed ACOMP to follow weight average polymer mass Mw, conversion, and reduced viscosity online.  The evolution of polydispersity during some reactions can also be approximately monitored.  ACOMP has also been applied to continuous reactors, determination of chain transfer constants, chain growth and step growth reactions, controlled radical polymerization, and copolymerization.

  The method involves continuously withdrawing a small stream of liquid from the reactor (usually 2 to 40 microliters per minute) and continuously diluting it with solvent from a reservoir (usually at 0.5 to 2 mL per minute).  The dilute solution is continuously pumped through a chain of detectors comprising:  A homebuilt 7 angle light scattering flow chamber, homebuilt single capillary viscometer, Shimadzu ultraviolet detector (UV) and a Waters 410 Refractive index detector (RI).
    For chain growth reactions the UV and RI detectors allow the amount of polymer and monomer at any instant to be determined, at least for monomers with double bonds that are lost upon polymerization.  With the polymer concentration known, the light scattering detector permits continuous determinations of Mw to be made, as well as root mean square radius of gyration, if the molecule is large enough.
 

Polymer Laboratories has recently entered into a licensing agreement with Tulane University to commercialize entire, customized ACOMP platforms.

ACOMP Instrumentation

Reactor/withdrawal/dilution stage, the "front-end". (photo courtesy of Mike Drenski)

The ACOMP detection train or "back-end", (front-end visible in the Fume Hood)

 

 

7 angle light scattering unit and Shimadzu UV detectors. (Photo courtesy of Dr. Jean-Luc Brousseau)

 The 7 angle light scattering unit has recently been commercialized as the BI-MwA from Brookhaven Instruments


 

Typical ACOMP Results

Raw data for styrene/methyl methacrylate copolymerization. (reference 10, below)

 

Weight average molecular mass Mw vs. conversion for polyacrylamide polymerization (reference 5, below)
Giz, Giz, Alb, Brousseau and Reed

Conversion data vs. time for polyacrylamide polymerization (reference 5, below)
Giz, Giz, Alb, Brousseau and Reed

 

Online monitoring of polydispersity, without chromatographic columns

There are several ways to follow the evolution of polydispersity during online monitoring;  use of the reciprocal light scattering envelope to obtain a direct measure of Mz/Mw,  the combining of simultaneous Mw from light scattering and viscosity average mass from viscosity.  When the reaction involves chains which propagate and die in a time short compared to the time for total conversion of monomer to polymer, the cumulative Mw can be differentiated to yield the instantaneous value Mw,inst, from which the various averages (Mn, Mz) can be computed.





ACOMP and free radical copolymerization
(reference 10, below)
Exploiting the differences in spectroscopic properties of monomers and their corresponding polymers, we have recently been able to apply ACOMP to the determination of average composition and mass distributions in a model-independent fashion.  If models are invoked (e.g. Mayo-Lewis), then we can also compute full composition, mass and sequence length distributions, as well as reactivity ratios.      
   Below are examples of the free radical copolymerization of styrene and methyl methacrylate.

copol1


copol2


copol3


Evolution of Mw, from ACOMP
(GPC values of final product are the solid circles)



copol5

copol6

ACOMP and Controlled Radical Polymerization (CRP)

Under the right conditions, CRP resembles "living" polymerization, where Mw grows linearly with conversion. (reference 9, below)



Controlled Radical Copolymerization

ACOMP was recently used to determine the composition profile of gradient copolymers synthesized via CRP. (reference 17, below)





References

ACOMP Publications
Appeared or in press

1. Fabio H. Florenzano, Roland Strelitzki and W.F. Reed, "Absolute, Online Monitoring
of Polymerization Reactions", Macromolecules, vol. 31, no. 21, 7226-7238, 1998

2. J-L Brousseau, H. Ç. Giz, and W. F. Reed, "Automatic, Simultaneous Determination
of Differential Refractive Index of a Polymer and its Corresponding Monomer", J. App.
Polym. Sci., 77, 3259-3262, 2000

3. W.F. Reed, "A Method for Online Determination of Polydispersity during
Polymerization Reactions", Macromolecules, 33, 7165-7172, 2000

4. W.F. Reed, "Breaking new ground in polymer science with molecular weight
analysis", invited article, American Laboratory, vol. 32, 16, 20-25, 8/2000

5. A. Giz, H. Giz, J.L. Brousseau, A. Alb, and W.F. Reed, "Kinetics and Mechanism of
Acrylamide Polymerization by Absolute, Online Monitoring of Polymerization
Kinetics", Macromolecules, vol. 34, 5, 1180-1191, 2001

6. A. Giz, H. Giz, J.L. Brousseau, A. Alb and W.F. Reed, "Online Monitoring of a
Stepwise Polymerization Reaction: Polyurethane", J. App. Polym. Sci., vol. 82, 2070-
2077, 2001

7. Bruno Grassl, Alina Alb and Wayne F. Reed, " Free radical transfer rate determination
using online polymerization monitoring", Macromolecular Chemistry and Physics, vol.
202, 12, 2518-2524, 2001

8. Bruno Grassl and Wayne F. Reed, "Online polymerization monitoring in a continuous
tank reactor", Macromolecular Chemistry and Physics, 203, 586-597, 2002

9. Florence Chauvin, Alina M. Alb, Denis Bertin, and Wayne F. Reed, "Kinetics and
molecular weight evolution during controlled radical polymerization", Macromolecular
Chemistry and Physics, 203, no. 14, 2029-2040, 2002

10. Ahmet Giz, Aysegul Oncul Koc, Huceste Giz, Alina Alb, and Wayne F. Reed
"Online monitoring of reactivity ratios, composition, sequence length, and molecular
weight distributions during free radical copolymerization". Macromolecules, 35, 6557-
6571, 2002.

11. Wayne F. Reed, "Monitoring Kinetic Processes in Polymer Solutions with Time
Dependent Static Light Scattering (TDSLS)", Ch. 12, pp. 131-151, in Scattering Methods
for the Investigation of Polymers, J. Kahovec, Ed., Wiley VCH, 2002

12. W. F. Reed, A. M. Alb, E. Mignard, H. Giz, A. Giz, F. H. Florenzano, R. Farinato
"Automatic Continuous Online Monitoring of Polymerization Reactions (ACOMP) ",
Polymeric Materials: Science and Engineering, 88, 476-478, 2003

13. E. Mignard, O. Guerret, D. Bertin, W.F. Reed, "Automatic Continuous Online
Monitoring of Polymerization Reactions (ACOMP) of High Viscosity Reactions",
Polymeric Materials: Science and Engineering, 88, 314-316, 2003

14. W. F. Reed, "Automatic, Continuous Mixing Techniques for Online Monitoring of
Polymer Reactions and for the Determination of Equilibrium Properties", ch. 20, pp. 589-
622, Handbook of Size Exclusion Chromatography and Related Techniques", 2nd Ed.,
Chi-san Wu, Ed., Marcel Dekker, 2003

15. Huceste Çatalgil-Giz, Ahmet Giz, Alina M. Alb, Wayne F. Reed, "Absolute Online
Monitoring of Acrylic acid Polymerization and the Effect of Salt and pH on Reaction
Kinetics", J. Applied Polymer Science, 91, 1352-1359, 2004

16. Didem Sunbul, Huceste Catalgil-Giz, Wayne F. Reed, Ahmet Giz, "An error in
variables method for determining the reactivity ratios by on-line monitoring of
copolymerization reactions", Macromolecular Theory and Simulation, 13, 162-168, 2004

17. Emmanuel Mignard, Thierry Leblanc, Denis Bertin, Olivier Guerret, Wayne F. Reed
"Online monitoring of controlled radical polymerization : Nitroxide mediated gradient
copolymerization", Macromolecules, 37, 966-975, 2004

18. Wayne F. Reed, "Automatic Continuous Online Monitoring of Polymerization
reactions (ACOMP)", invited review for Polymer News, in press
Submitted or in preparation

19. J. Calbick, R. Farinato, G.A. Sorci, Fabio H. Florenzano, and W.F. Reed, "Online
monitoring of rapid growth and branching in the stepgrowth polymerization of
polyamines”, submitted

20. Fabio H. Florenzano, Vanessa Fleming, Pascal Enohnyaket, W.F. Reed, "Coupling
of Near Infra-Red spectroscopy to Automatic Continuous Online Monitoring of
Polymerization Reactions", submitted

21. J.F. Lutz, E. Mignard, K. Matjyewski, O. Guerret, and W.F. Reed, "Online
monitoring of Atom Transfer Radical Polymerization", in preparation.

22. H. Çatalgil-Giz, A. Giz, A.M. Alb, W.F. Reed , " Absolute Online Monitoring of Acrylic acid Polymerization and the Effect of Salt and pH on Reaction Kinetics", J. Applied Polymer Science, 91, 1352-1359, 2004

23. Didem Sunbul, H. Catalgil-Giz, W.F. Reed, A. Giz, "An error in variables method for determining the reactivity ratios by on-line monitoring of copolymerization reactions", Macromolecular Theory and Simulation, 13, 162-168, 2004

24. E. Mignard, T. Leblanc, D. Bertin, O. Guerret, W.F. Reed, "Online monitoring of controlled radical polymerization: Nitroxide mediated gradient copolymerization", Macromolecules, 37, 966-975, 2004

25. W.F. Reed, "Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP)", Feature Article, Polymer News, 29, 271-279, 2004

26. F.H. Florenzano, V. Fleming, P. Enohnyaket, W.F. Reed, "Coupling of Near Infra-Red spectroscopy to Automatic Continuous Online Monitoring of Polymerization Reactions", European Polymer Journal, 41, 535-545, 2005

27. R.S. Farinato, J. Calbick, G.A. Sorci, F.H. Florenzano, W.F. Reed, "Online monitoring of the final divergent growth phase in the stepgrowth polymerization of polyamines" Macromolecules, 38, 1148-1158, 2005

28. E. Mignard, J-F Lutz, T. Leblanc, K. Matyjaszewski, O. Guerret, W.F. Reed, “Kinetics and Molar Mass Evolution during Atom Transfer Radical Polymerization of n-Butyl Acrylate Using Automatic Continuous Online Monitoring.” Macromolecules, 38, 9556-9563, 2005

29. A.M. Alb, R. Farinato, J. Calbeck, W.F. Reed, “Online monitoring of polymerization reactions in inverse emulsions”, Langmuir, 22, 831-840, 2006

30. A.M. Alb, P. Enohnyaket, M. Drenski, A. Head, A.W. Reed, W.F. Reed, “Online monitoring of copolymerization using comonomers of similar spectral characteristics”, Macromolecules, 39, 5705-5713, 2006

31. A.M. Alb, P. Enohnyaket, R. Shunmugam, G.N. Tew, W.F. Reed, “Quantitative contrasts in the copolymerization of acrylate and methacrylate monomers”, Macromolecules, 39, 8283-8292, 2006

32. M.F. Drenski, E. Mignard , W.F. Reed, “Direct Measurement of Chain Transfer during Controlled Radical Polymerization”, Macromolecules, 39, 8213-8215, 2006

33. A.M. Alb, P. Enohnyaket, J.F. Craymer, T. Eren, E.B. Coughlin, W.F. Reed, “Online monitoring of Ring Opening Metathesis Polymerization of Cyclooctadiene and a Functionalized Norbornene”, Macromolecules, 40, 444-451, 2007

34. A.M. Alb, A. Paril, H. Çatalgil-Giz, A. Giz, W. F. Reed , “Evolution of composition, molar mass, and conductivity during the free radical copolymerization of polyelectrolytes”, accepted by J. Phys. Chem. 3/07

35. A. Paril, A.M. Alb, W.F. Reed, “ Online Monitoring of the Evolution of Polyelectrolyte Characteristics during Postpolymerization Modification Processes” Macromolecules, 40, 4409-4413, 2007

36. A.M. Alb, M. F. Drenski, W.F. Reed, "Monitoring of Polymerization and other Polymeric Processes in Solution", invited article for Progress in Polymer Science. In press.