RELATIONSHIPS BETWEEN COPOLYMERIZATION KINETICS AND STRUCTURAL PROPERTIES OF ACRYLAMIDE/ACRYLIC ACID COPOLYMER

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1 RELATIONSHIPS BETWEEN COPOLYMERIZATION KINETICS AND STRUCTURAL PROPERTIES OF ACRYLAMIDE/ACRYLIC ACID COPOLYMER May 6, 2015 Marzieh Riahinezhad, Neil McManus, Alexander Penlidis

2 Outline 2 Introduction Acrylamide/Acrylic Acid Copolymer Copolymer Applications & Requirements Research Goals Results & Discussion Copolymerization Kinetics: Refinement/Clarification Stage Copolymer Properties: Characterization Stage Design & Test the Copolymer for EOR applications: Application Stage Concluding Remarks

3 Acrylamide (AAm)/Acrylic Acid (AAc) Copolymer 3 AAm AAc The ionization of AAc makes the copolymer a polyelectrolyte: Polyelectrolyte nature makes the copolymerization dependent on reaction medium

4 AAm/AAc Copolymer Applications 4 Main applications: Enhanced oil recovery (EOR) Flocculants (for waste water treatment or oil sands tailings reclamation) Drag reduction agents, etc. Enhanced oil recovery (EOR)

5 Requirements for the Copolymer in Target Applications 5 EOR M = μ O k W μ W k O High water solubility Good thickening Low retention High mechanical, thermal, chemical stability Need to tailor the molecular structure of the copolymer to meet the increasing and changing demands in applications

6 Research Goals & Emphasis 6 Knowledge of chain microstructural properties Polymerization kinetics Efficient polymers for EOR Tailor-made AAm/AAc copolymers Knowledge of bulk macrostructural properties Structural properties

7 Clarification of Reaction Kinetics Stage 1 7 Main factors: Ionic strength ph, monomer concentration, & monomer composition in feed Responses: Reactivity ratios Monomer conversion Copolymer composition Molecular weight Monomer sequence length Factorial/D-Optimal Design Run [M] ph f 0AAm , , , , , , , , ,

8 raac Ionic Strength Effect on Reactivity Ratios Reactivity ratio trends: Adding salt in reaction solution, r AAc remained almost unchanged; r AAm decreased significantly Controlled IS (0.898 M salt) Constant IS (0.359 M salt) Controlled IS (0.539 M salt) Variable IS raam AAm/AAc copolymerization, ph=7, IS: Ionic strength, Salt: NaCl

9 Conversion (%) Monomer Composition Effect on Reaction Rate f 0AAm =0.85 Higher AAm in the feed, 80 f 0AAm =0.46 Higher reaction rate (due to the less electrostatic repulsions between negatively charged reacting species) Time (min) f 0AAm =0.1 Conversion versus time profiles for AAm/AAc copolymerization at constant ionic strength

10 ph Effect on Copolymer Composition F AAm f 0AAm ph=3 ph=5 ph=7 Cum F AAm ph=3 ph=5 ph= Conversion % Copolymerization at [M]=0.5 Copolymerization at [M]=1 & f 0AAm =0.46 Instantaneous copolymer composition: By moving from ph=3 to 7, a reversal in the behavior of the instantaneous copolymer composition Cumulative copolymer composition: ph=3, upward composition drift ph=5, no composition drift ph=7, downward composition drift

11 Mp Peak Average Molecular Weight 11 Effect of monomer concentration: Higher monomer concentration, higher copolymer MW 7.E+06 6.E+06 5.E+06 4.E Effect of f 0AAm : Higher AAm mole fraction in the feed, higher copolymer MW 3.E+06 2.E+06 1.E E+00 [M]=0.5 [M]=1.0 [M]=1.5 Copolymerization at ph=3 Numbers on bars represent f 0AAm

12 12 Sequence Length Distribution of AAm in Copolymer (N AAm ) l ph=3, r AAc > r AAm f0aam=0.10 f0aam=0.46 (N AAm ) l ph=7, r AAc < r AAm f0aam=0.10 f0aam= Sequence Length, l Sequence Length, l Effect of monomer composition in the feed: Higher AAm monomer fraction in the feed, broader AAm sequence length distribution Effect of reaction ph: Higher ph, broader AAm sequence length distribution

13 Shear Viscosity (Pa.s) Shear Viscosity Characterization of Copolymer Properties Stage Shear rate=5 1/s FAAm FAAm=0.96 FAAm=0.87 FAAm=0.77 FAAm= FAAm= FAAm=0.44 FAAm= Shear Rate (1/s) Counterbalancing effects of acrylate content & molecular weight on shear thinning behavior.

14 Elastic & Viscous Modulus (Pa) Characterization of Copolymer Properties Frequency Sweep (10% strain) (FAAm=0.67), G' Frequency (Hz) (FAAm=0.67), G" (FAAm=0.77), G' (FAAm=0.77), G" (FAAm=0.86), G' (FAAm=0.86), G" (FAAm=0.93), G' (FAAm=0.93), G" More AAc, higher G & G, more elastic behavior

15 Design of Copolymer for a Specific Application Stage 3 15 Copolymer Properties # F AAm MW (g/mol) Shear 1 (1/s) G & G crossover (Hz) ~ 2.5E Designing the AAm/AAc copolymer for EOR applications based on knowledge of copolymerization kinetics

16 Resistance Factor Residual Resistance Factor Testing Copolymer Performance in EOR 16 Polymer Flooding Test Tailor-made copolymer Commercial copolymer Pore volume of injected fluid Pore volume of injected fluid Tailor-made copolymer Commercial copolymer Flow behavior of the tailor-made polymer solution in porous media (sand-pack): Higher resistance factor: Better effective viscosity & mobility control Good residual resistance factor: Low retention of polymer solution

17 Concluding Remarks 17 A comprehensive investigation was conducted in order to acquire detailed knowledge of the factors controlling copolymerization kinetics. A general framework for the relationships between reaction kinetics and copolymer microstructure was obtained. AAm/AAc copolymers with desirable properties for enhanced oil recovery applications were designed and tested (long experiments). Tailor-made AAm/AAc copolymer showed better performance compared to a commercially available polymer of the same type.

18 Thank You!

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20 Representative References 20 Riahinezhad, M., Kazemi, N., McManus, N., Penlidis, A., J. Polym. Sci., Polym. Chem., 51, 22, Rintoul I., Wandrey C., Polym., 46, 13, Paril A., Alb A. M., Giz A. T., Çatalgil-Giz H., J. Appl. Polym. Sci., 103, 2, Riahinezhad, M., Kazemi, N., McManus, N., Penlidis, A., J. Appl. Polym. Sci., 131, 20, Ponratnam S., Kapur S. L., Makromol. Chem., 178, 4, Riahinezhad, M., McManus, N., Penlidis, A., Macromol. React. Eng., 9, 2, Kurenkov V. F., Trofimov P. V., Kurenkov A. V., Khartan K., Lobanov F. I., Russ. J. Appl. Chem., 78, 6, Hunkeler D., Wu X. Y., Hamielec A. E., J. Appl. Polym. Sci., 46, 4, Cabaness W. R., Lin T. Y. C., Párkányi C., J. Polym. Sci., Polym. Chem., 9, 8, 1971.

21 21 Sandpack flooding experimental setup

22 raam raac Reactivity Ratios with Respect to ph & Monomer Conc By increasing ph from 3 to 7, r AAm increased; r AAc decreased M, raam 1.0 M, raam 1.5 M, raam 0.5 M, raac 1.0 M, raac M, raac ph 0