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The Waterborne Symposium

Environmentally Friendly Coating Technologies

Mission Statement:

To administer the preeminent educational/technical forum in the United States directed to the science and technology of surface coatings and  to provide revenue to support and advance the School of Polymers and High Performance Materials at The University of Southern Mississippi.


Natalie Leonardi - Automatic Control of Polymer Molecular Weight and Copolymer Composition, and Synthesis of Multimodal Molecular Weight Distributions (MWD)


Natalie Leonardi - Automatic Control of Polymer Molecular Weight and Copolymer Composition, and Synthesis of Multimodal Molecular Weight Distributions (MWD)


Natalie Leonardi
Research Engineer
Advanced Polymer Monitoring

Address: 1078 South Gayoso Street, New Orleans, LA 70125

Phone: 504-777-2805
Website: www.apmtinc.com


Automatic Control of Polymer Molecular Weight and Copolymer Composition, and Synthesis of Multimodal Molecular Weight Distributions (MWD)

Natalie Leonardi,2 Terry McAfee,1 Rick Montgomery,2 Julia Siqueira,1,3 Thomas Zekoski,1 Michael F. Drenski, 2 Wayne F. Reed 1,*

1 Tulane University, New Orleans, Louisiana, 70118, USA
2 Advanced Polymer Monitoring Technologies, Inc., New Orleans, Louisiana, 70125
3 On leave from Universidade de São Paulo, Lorena, Brazil
* Correspondence, wreed@tulane.edu

Automatic Continuous Online Monitoring Polymerizations (ACOMP) data was used to control monomer concentration and weight average molecular weight of linear chain growth free radical polymerizations. The model-free feedback controller allowed reactions to follow specific molecular weight trajectories to produce desired final MWD.   One application was to produce multimodal molecular weight distributions during a single reaction without the need for post-processing of the final product. Typically, multimodal populations are achieved through blending, which can result in the degradation of the polymer and can also be a bottleneck in the event of increasing plant throughput. The ACOMP system was used to continuously extract and measure monomer concentration and weight average molecular weight using a UV/Vis and a 7-angle light scattering detector.  Instead of using a complex kinetic model the controller simply utilizes two proportionality constants calculated from ACOMP data to control monomer concentration and molecular weight in the reactor; i. Alpha, the rate of polymerization is proportional to monomer concentration, ii. Instantaneous weight average molecular weight, Mwinst, is proportional to monomer concentration. The continuous calculation of the Mwinst also allows for online chromatography-free molecular weight distributions if well-known forms for instantaneous MWD are used. The multimodal distributions were achieved by controlling the monomer feed into to the reactor and automatically adding chain transfer agent (CTA) to produce a subsequent, lower molecular weight population. The amount of CTA was based on a predetermined ratio of CTA to monomer and added once a desired amount of polymer concentration at a certain mode was reached. The controller has been successfully used for comonomer composition control by computing comonomer conversion kinetics and instantaneous comonomer fraction, and automatically adjusting the feed rate of each comonomer into the reactor. This approach to polymer production can be further expanded to tailor polymers to achieve specific properties and functions.


Natalie Leonardi is a chemical engineer with experience in multiple science-based engineering roles. She began her professional career as a process engineer at a monomer production plant where she optimized production processes and minimized batch fluctuations. Additionally, Natalie was a project manager for a tablet coatings and excipient company and a process engineer for a Colombian exploration and production company.

In 2015 Natalie joined APMT as the Research and Applications Engineer. In this scope, Natalie works with customer polymer chemistries, manages R&D projects and researches new product applications. At APMT she became one of the world’s first polymer “controlonauts,” controlling the free radical polymerization of acrylamide. Most recently, Natalie’s work contributed to the APMT development of automated control of polymer molecular weight in real time.

Natalie is a member of the American Institute of Chemical Engineers, and she has authored and co-authored many scientific articles for trade journals and scientific publications like Macromolecules. Natalie holds a B.S. from Drexel University in Chemical Engineering and minors in Economics and International Economics.

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