Journal of Coatings Technology

, Volume 74, Issue 925, pp 49–63 | Cite as

Interdiffusion and crosslinking in thermoset latex films

  • Mitchell A. Winnik
Technical Articles


Thermoset latex systems represent an attractive approach to obtaining the high performance needed in many different kinds of industrial coatings, while satisfying the growing requirement for environmental friendliness. In these coatings in the dispersed state, the reactive groups are packaged inside of polymer particles. These latex particles deform as the coating dries to form a transparent binder phase. The useful properties of mechanical strength, as well as scrub and solvent resistance, develop over time. This paper focuses on the idea that to achieve the desired properties in a thermoset latex coating, one has to pay proper attention to the relative rates of polymer diffusion and crosslinking in the coating. Strength in these films develops as a consequence of chains that connect crosslink points on opposite sides of interface formed between adjacent particles in the film. Thus polymer diffusion must precede extensive bond formation created by the crosslinking chemistry. This paper reviews fundamental concepts and then describes experiments in three separate systems. These experiments show that the formulator has three main strategies to vary the relative rates of these processes: 1. Catalyst strength and concentration will affect the reaction rate. 2. Polymer chain length will affect the polymer diffusion rate. 3. Temperature changes will normally have a larger affect on the polymer diffusion rate than on the crosslinking reaction rate.


Melamine Latex Particle PTSA Latex Film Butyl Methacrylate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. (1).
    Taylor, J.W. and Winnik, M.A., “Functional Latex and Thermoset Latex Films,” to be published.Google Scholar
  2. (2)(a).
    Bufkin, B.G. and Grawe, J.R., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part I,”Journal of Coatings Technology,50, No. 641, 41–55 (1978);Google Scholar
  3. (2)(b).
    Grawe, J.R. and Bufkin, B.G., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part II,”Journal of Coatings Technology,50, No. 643, 67–83 (1978);Google Scholar
  4. (2)(c).
    Bufkin, B.G. and Grawe, J.R., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part III,”Journal of Coatings Technology,50, No. 644, 83–109 (1978);Google Scholar
  5. (2)(d).
    Grawe, J.R. and Bufkin, B.G., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part IV,”Journal of Coatings Technology,50, No. 645, 70–100 (1978);Google Scholar
  6. (2)(e).
    Bufkin, B.G. and Grawe, J.R., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part V,”Journal of Coatings Technology,50, No. 647, 65–96 (1978);Google Scholar
  7. (2)(f).
    Grawe, J.R. and Bufkin, B.G., “Survey of the Applications, Properties, and Technology of Crosslinking Emulsions Part VI,”Journal of Coatings Technology,51, No. 649, 34–67 (1978);Google Scholar
  8. (2)(g).
    Yeliseeva, V. I. “Crosslinking of Latex Polymers,”Br. Polym. J., 7, 33–49 (1975).CrossRefGoogle Scholar
  9. (3)(a).
    Winnik, M.A., “Latex Film Formation,”Curr. Op. Coll. Interfac. Sci., 2, 192–199 (1997);CrossRefGoogle Scholar
  10. (3)(b).
    Winnik, M.A., “The Formation and Properties of Latex Films,” inEmulsion Polymerization and Emulsion Polymers, Lovell, P. and El-Aasser, M.S. (Eds.), Ch. 14, 467–518, 1997;Google Scholar
  11. (3)(c).
    Keddie, J.L., “Film Formation of Latex,”Mat. Sci. Eng., 21, 101–170 (1997);CrossRefGoogle Scholar
  12. (3)(d).
    Provder, T., Winnik, M.A., and Urban, M.W. (Eds.), “Film Formation in Waterborne Coatings,”ACS Symp. Ser. 648, Amer. Chem. Soc., Washington, D.C., 1996.Google Scholar
  13. (4)(a).
    Zosel, A. and Ley, G., “Influence of Crosslinking on Structure, Mechanical Properties and Strength of Latex Films,”Macromolecules, 26, 2222–2227 (1993);CrossRefADSGoogle Scholar
  14. (4)(b).
    Tamai, T., Pinenq, P., and Winnik, M.A., “Effect of Crosslinking on Polymer Diffusion in Poly(butyl methacrylate-co-butyl acrylate) Latex Films,”Macromolecules, 32, 6102–6110 (1999).CrossRefADSGoogle Scholar
  15. (5).
    Doi, M. and Edwards, S.F.,The Theory of Polymer Dynamics, Oxford University Press, Oxford, England, 1986.Google Scholar
  16. (6).
    de Gennes, P.G.,Scaling Concepts in Polymer Physics, Cornell University Press, Ithaca, NY, 1979.Google Scholar
  17. (7).
    de Gennes, P.G. “Couples de Polymères Compatibles: Propriétés Spéciales en Diffusion et en Adhésion,”C. R. Seances Acad. Sci., Ser. 2, 292, 1505–1507 (1981);Google Scholar
  18. (7)a.
    de Gennes, P.G., “Dynamics of Fluctuations and Spinodal Decomposition in Polymer Blends,”J. Chem. Phys., 72, 4756–4763 (1980);MATHCrossRefADSMathSciNetGoogle Scholar
  19. (7)b.
    de Gennes, P.G. “Tension Superficielle des Polymères Fondus,”C. R. Acad. Sci., Ser. 2, 307, 1841–1844, 1988.Google Scholar
  20. (8).
    Prager, S. and Tirrell, M., “The Healing Process at Polymer-Polymer Interfaces,”J. Chem. Phys., 5194–5198 (1981).Google Scholar
  21. (9).
    Wool, R.P. and O’Connor, K.M., “A Theory of Crack Healing in Polymers,”J. Appl. Phys., 52, 5953–5963 (1981);CrossRefADSGoogle Scholar
  22. (9)a.
    Wool, R.P. and O’Connor, K.M., “Time Dependence of Crack Healing,”J. Polym. Sci., Polym. Lett. Ed., 20, 7–16 (1982).CrossRefGoogle Scholar
  23. (10).
    Wool, R.P.,Polymer Interfaces, Hanser Publishers, 1995.Google Scholar
  24. (11).
    Crank, J.,The Mathematics of Diffusion, Clarendon, Oxford, U.K., 1975.Google Scholar
  25. (12).
    Ferry, J.D.,Viscoelastic Properties of Polymers, 3rd ed, Wiley, New York, Chapter 11, 1980.Google Scholar
  26. (13).
    Nemoto, N., Landry, M.R., Nob, I., and Yu, H., “Temperature Dependence of the Self Diffusion Coefficient of Polyisoprene in the Bulk State,”Polymer Commun., 25, 141–143 (1984);Google Scholar
  27. (13)(b).
    Chen, S.J. and Ferry, J.D., “The Diffusion of Radioactively Tagged n-Hexadecane and n-Dodecane Through Rubbery Polymers. Effects of Temperature, Crosslinking and Chemical Structure,”Macromolecules, 1, 270–278 (1968).CrossRefADSGoogle Scholar
  28. (14).
    Birks, J.B.,Photophysics of Aromatic Molecules, Wiley-Interscience, London, 1970.Google Scholar
  29. (15).
    Liu, Y.S., Feng, J., and Winnik, M.A., “Study of Polymer Diffusion Across the Interface in Latex Films Through Direct Energy Transfer Experiments,”J. Chem. Phys., 101, 9096–9103 (1994);CrossRefADSGoogle Scholar
  30. (15)(a).
    Winnik, M.A., Li, L., and Liu, Y.S., “Fluorescence Decay Studies of Polymer Diffusion Across Interfaces in Latex Films,” inMicrochemistry: Spectroscopy and Chemistry in Small Domains, Masuhara, H. and Kitamura, N. (Eds.), Elsevier, Holland, pp. 387–400, (1994);Google Scholar
  31. (15)(b).
    Dhinojwala, A. and Torkelson, J.M., “A Reconsideration of the Measurement of Polymer Interdiffusion by Fluorescence Nonradiative Energy Transfer,”Macromolecules, 27, 4817–4824 (1994).CrossRefADSGoogle Scholar
  32. (16).
    Kim, H.-B. and Winnik, M.A., “Factors Affecting Interdiffusion Rates in Films Prepared from Latex Particles with a Surface Rich in Acid Groups and Their Salts,”Macromolecules, 28, 2033–2041 (1995).CrossRefADSGoogle Scholar
  33. (17).
    Yekta, A., Duhamel, J., and Winnik, M.A., “Dipole-Dipole Electronic Energy Transfer. Fluorescence Decay Functions for Arbitrary Distributions of Donors and Acceptors: Systems With Planar Geometry,”Chem. Phys. Lett., 235, 119–125 (1995).CrossRefADSGoogle Scholar
  34. (18).
    Farinha, J.P.S., Martinho, J.M.G., Yekta, A., and Winnik, M.A., “Direct Nonradiative Energy Transfer in Polymer Interphases: Fluorescence Decay Functions from Concentration Profiles Generated by Fickian Diffusion,”Macromolecules, 28, 6084–6088 (1995).CrossRefADSGoogle Scholar
  35. (19)(a).
    Winnik, M.A., Wang, Y., and Haley, F., “Latex Film Formation at the Molecular Level: The Effect of Coalescing Aids on Polymer Diffusion,”Journal of Coatings Technology,64, No. 811, 51–61 (1992);Google Scholar
  36. (19)(b).
    Wang, Y. and Winnik, M.A., “Polymer Diffusion Across Interfaces in Latex Films,”J. Phys. Chem. 97, 2507–2515 (1993);CrossRefGoogle Scholar
  37. (19)(c).
    Goh, M.C., Juhué, D., Leung, O.-M., Wang, Y., and Winnik, M.A., “Annealing Effects on the Surface Structure of Latex Films Studied by Atomic Force Microscopy,”Langmuir, 9, 1319–1322 (1993);CrossRefGoogle Scholar
  38. (19)(d).
    Kim, H.-B., Wang, Y., and Winnik, M.A., “Synthesis, Structure and Film-Forming Properties of Poly(butyl methacrylate)-poly(methacrylic acid) Core-Shell Latex,”Polymer, 35, 1779–1786 (1994);CrossRefGoogle Scholar
  39. (19)(e).
    Winnik, M.A. and Liu, Y.S., “Direct Non-Radiative Energy Transfer Studies of Interdiffusion Latex Films: Strategies for Data Analysis,”Makromol. Symp., 92, 321–331 (1995);Google Scholar
  40. (19)(f).
    Feng, J., Winnik, M.A., Shivers, R.R., and Clubb, B., “Polymer Blend Latex Films: Morphology and Transparency,”Macromolecules, 28, 7671–7682 (1995);CrossRefADSGoogle Scholar
  41. (19)(g).
    Winnik, M.A. and Feng, J., “Latex Blends: An Approach to Zero VOC Coatings,”Journal of Coatings Technology,68, No. 852, 39–50 (1996);Google Scholar
  42. (19)(h).
    Farinha, J.P.S., Martinho, J.M.G., Kawaguchi, S., Yekta, A., and Winnik, M.A., “Latex Film Formation Probed by Nonradiative Energy Transfer: Effect of Grafted and Free Poly(ethylene oxide) on a Poly(n-butyl methacrylate) Latex,”J. Phys. Chem., 100, 12552–12558 (1996);CrossRefGoogle Scholar
  43. (19)(i).
    Feng, J., Winnik, M.A., and Siemiarczuk, A., “Interface Characterization in Latex Blend Films by Fluorescence Energy Transfer,”J. Polym. Sci: Part B: Polym. Phys., 36, 1115–1128 (1998);CrossRefADSGoogle Scholar
  44. (19)(j).
    Feng, J., Pham, H., Stoeva, V., and Winnik, M.A., “Polymer Diffusion in Latex Films at Ambient Temperature,”J. Polym. Sci.: Part B: Polym. Phys., 36, 1129–1139 (1998);CrossRefADSGoogle Scholar
  45. (19)(k).
    Feng, J., Odrobina, E., and Winnik, M.A., “Effect of Hard Polymer Filler Particles on Polymer Diffusion in a Low-T8 Latex Film,”Macromolecules, 31, 5290–5299 (1998);CrossRefADSGoogle Scholar
  46. (19)(l).
    Odrobina, E., Feng, J., and Winnik, M.A., “Effect of Oligomers on the Polymer Diffusion Rate in Poly(butyl methacrylate) Latex Films.,”J. Polym. Sci. Part A: Polym. Chem., 39, 3933–3943 (2000).CrossRefADSGoogle Scholar
  47. (20).
    Boczar, E.M., Dionne, B.C., Fu, Z., Kirk, A.B., Lesko, P.M., and Koller, A.D., “Spectroscopic Studies of Polymer Inter-Diffusion During Film Formation,”Macromolecules, 28, 5772–5781 (1993).CrossRefADSGoogle Scholar
  48. (21).
    Juhué, D. and Lang, J., “Film Formation from Dispersion of Core-Shell Latex Particles,”Macromolecules, 28, 1306–1308 (1995).CrossRefADSGoogle Scholar
  49. (22).
    Feng, J., Pham, H., Macdonald, P., Winnik, M.A., Geurts, J.M., Zirkzee, H., van Es, S., and German, A.L., “Formation and Crosslinking of Latex Films through the Reaction of Acetoacetoxy Groups with Diamines under Ambient Conditions,”Journal of Coatings Technology,70, No. 881, 57–68 (1998).CrossRefGoogle Scholar
  50. (23).
    Liu, R., Winnik, M.A., DiStefano, F., and Vanketessan, J., “Interdiffusion vs. Crosslinking Rates in Isobutoxyacrylamide-Containing Latex Coatings,”Macromolecules, 34, 7306–7314 (2001).CrossRefADSGoogle Scholar
  51. (24).
    The value of 38 kcal/mol we obtained for experiments in the range of 70 to 100°C were essentially identical to that obtained by the Ferry group from dynamic mechanical measurements on PBMA (37 kcal/mol at 100°C): Child, W.C. and Ferry, J.D., “Dynamic Mechanical Properties of Poly(butyl methacrylate),”J. Colloid Sci., 12, 327–341 (1957);CrossRefGoogle Scholar
  52. (24)(a).
    Ferry, J.D. and Strella, S., “Dielectric Dispersion of Methacrylate Polymers and Its Correlation with Mechanical Properties,”J. Colloid Sci., 13, 459–471 (1958).CrossRefGoogle Scholar
  53. (25).
    Wang, Y. and Winnik, M.A., “Energy-Transfer Study of Polymer Diffusion in Melt-Pressed Films of Poly(methyl methacrylate),”Macromolecules, 26, 3147–3150 (1993).CrossRefADSGoogle Scholar
  54. (26).
    Winnik, M.A., Pinenq, P., Krüger, C., Zhang, J., and Yaneff, P.V., “Crosslinking vs. Interdiffusion Rates in Melamine-Formaldehyde Cured Latex Coatings: A Model for Waterborne Automotive Basecoat,”Journal of Coatings Technology,71, No. 892, 47–60 (1999).CrossRefGoogle Scholar
  55. (27)(a).
    Hahn, K.G., Thermosetting Acrylic Latexes, U.S. Patent 4,812,491 (1989);Google Scholar
  56. (27)(b).
    Kunz, B.L. and Hahn, K.G., Pigmented Low Cure Emulsion Polymers, U.S. Patent 4,981,883 (1991).Google Scholar
  57. (28)(a).
    Taylor, J.W., “A Study on the Chemistry of Alkylcarbodiimide Ethyl Methacrylates as Reactive Monomers for Acrylic and Vinyl Ester-based Latexes,”Proc. XXIVth International Conference in Organic Coatings Science and Technology, Athens, Greece, (1995);Google Scholar
  58. (28)(b).
    Taylor, J.W., Collins, M.-J., and Bassett, D.R., “A Study on the Chemistry of Alkylcarbodiimide Ethyl Methacrylates as Reactive Monomers for Acrylic and Vinyl Ester-based Latexes,”Prog. Org. Coat., 35, 215–221 (1999).CrossRefGoogle Scholar
  59. (29).
    Pham, H.H. “Polymer Interdiffusion vs. Crosslinking in Carboxylic Acid-Carbodiimide Latex Films,” Ph.D. Thesis, University of Toronto, 1999.Google Scholar
  60. (30).
    Pham, H.H. and Winnik, M.A., “Synthesis, Characterization, and Stability of Carbodiimide Groups in Carbodiimide-Functionalized Latex Dispersions and Films,”J. Polym. Sci. Part A, Polym. Chem., 38, 855–869 (2000).CrossRefADSGoogle Scholar
  61. (31)(a).
    Pham, H.H., Farinha, J.P.S., and Winnik, M.A., “Crosslinking, Miscibility, and Interface Structure in Blends of Poly(2-Ethylhexyl Methacrylate) Copolymers. An Energy Transfer Study,”Macromolecules, 33, 5850–5862 (2000);CrossRefADSGoogle Scholar
  62. (31)(b).
    Pham, H.H. and Winnik, M.A., “Film Formation from Blends of Carbodiimide and Carboxylic Acid-Functional Latex,” inFilm Formation in Coatings, Provder, T., Urban, M.W. (Eds.), ACS Symposium Series 790, Chapter 5, pp. 88–102, Washington, D.C. (2001).Google Scholar
  63. (32)(a).
    Pham, H.H. and Winnik, M.A., “Polymer Interdiffusion vs. Crosslinking in Carboxylic Acid-Carbodiimide Latex Films,”Macromolecules, 32, 7692–7695 (1999).CrossRefADSGoogle Scholar
  64. (33).
    Aradian, A., Raphaël, E., and de Gennes, P.-G. “Strengthening of a Polymer Interface: Interdiffusion and Crosslinking,”Macromolecules, 33, 9444–9451 (2000).CrossRefADSGoogle Scholar

Copyright information

© Springer Science+Business Media 2002

Authors and Affiliations

  • Mitchell A. Winnik
    • 1
  1. 1.University of TorontoCanada

Personalised recommendations