Journal of Coatings Technology and Research

, Volume 15, Issue 6, pp 1273–1282 | Cite as

Photooxidative stability provided by condensed tannin additives in acrylic-based surface coatings on exterior exposure

  • W. J. GrigsbyEmail author


Condensed tannins, also known as proanthocyanidins, have been added as functional additives to acrylic-based clear coatings to promote polymer coating longevity and also stabilize timber color on accelerated and exterior weathering. When added at < 0.5% w/w content, native tannins and tannins modified with maleate groups extended coating performance > 20% compared to commercial hindered amine light stabilizers (HALS) and phenolic stabilizers used at comparable coating loadings. Other tannin chemical modifications such as methylcarboxylate groups were also associated with greater coating longevity beyond that achieved with the synthetic UV and antioxidant additives. This study has also revealed that tannin addition to acrylic coatings can act to photostabilize timber coloring on exterior exposure. While tannin use can contribute color to coatings, any color was rapidly bleached on UV exposure with a dependency on tannin content, degree of modification, and coating formulation pH. Moreover, through manipulating tannin addition levels, this tannin decolorization could offset typical wood darkening associated with UV exposure to provide low or no wood color change over longer exposure periods. With the photooxidative stability efficacy of tannins established on exterior exposure, condensed tannins in native and modified form offer potential as sustainable functional additives for the coatings sector.


Condensed tannins Proanthocyanidins Functional additives Coatings Acrylics Styrene acrylics Exterior exposure Weathering 



This work was supported by Biopolymer Network Ltd, through funding by the New Zealand Ministry of Business, Innovation and Employment.

Supplementary material

11998_2018_86_MOESM1_ESM.docx (879 kb)
Supplementary material 1 (DOCX 879 kb)


  1. 1.
    Mash, A, Sustainability in the coatings industry. PCI Paints & Coatings Industry Magazine (2015).
  2. 2.
    Hare, CH, “Protective Coatings.” In: S.f.p. coatings (ed.) Fundamentals of Chemistry and Composition. Technology Publishing Company, Pittsburgh (1994)Google Scholar
  3. 3.
    Grigsby, WJ, “Simulating the Protective Role of Bark Proanthocyanidins in Surface Coatings: Unexpected Beneficial Photo-Stabilisation of Exposed Timber.” Prog. Organ. Coat., 110 55–61 (2017)CrossRefGoogle Scholar
  4. 4.
    Grigsby, WJ, et al., “Esterification of Condensed Tannins and Their Impact on the Properties of Poly(Lactic Acid).” Polymers, 5 (2) 344–360 (2013)CrossRefGoogle Scholar
  5. 5.
    Grigsby, WJ, et al., “Evaluating Modified Tannin Esters as Functional Additives in Polypropylene and Biodegradable Aliphatic Polyester.” Macromol. Mater. Eng., 299 (10) 1251–1258 (2014)CrossRefGoogle Scholar
  6. 6.
    Luo, C, et al., “Vegetable Oil Thermosets Reinforced by Tannin–Lipid Formulations.” Acta Biomater., 9 (2) 5226–5233 (2013)CrossRefGoogle Scholar
  7. 7.
    Hagerman, AE, Tannin Handbook. University of Miami, Ohio (2002)
  8. 8.
    Hemingway, RW, Karchesy, JJ, Branham, SJ, The Chemistry and Significance of Condensed Tannins. Plenum Press, New York (1989)CrossRefGoogle Scholar
  9. 9.
    Grigsby, WJ, Kadla, JF, “Evaluating Poly (Lactic Acid) Fiber Reinforcement with Modified Tannins.” Macromol. Mater. Eng., 299 (3) 368–378 (2014)CrossRefGoogle Scholar
  10. 10.
    Grigsby, WJ, Bridson, JH, Schrade, C, “Modifying Biodegradable Plastics with Additives Based on Condensed Tannin Esters.” J. Appl. Polym. Sci., 132 (11) 41626 (2014). Google Scholar
  11. 11.
    Grigsby, W, Steward D, “Applying the Protective Role of Condensed Tannins to Acrylic-Based Surface Coatings Exposed to Accelerated Weathering.” J. Polym. Environ., 26 (3) 895–905 (2018). CrossRefGoogle Scholar
  12. 12.
    Colombini, MP, et al., “Colour Fading in Textiles: A Model Study on the Decomposition of Natural Dyes.” Microchem. J, 85 (1 SPEC. ISS) 174–182 (2007)CrossRefGoogle Scholar
  13. 13.
    Durán, N, et al., “Biomass Photochemistry: VI-Light-Induced Oxidation of Phlobaphene from Wood.” Polym. Photochem., 6 (5) 393–402 (1985)CrossRefGoogle Scholar
  14. 14.
    Pizzi, A, et al., “Tannin Antioxidant Characteristics in Leather Versus Leather Light Stability: Models.” J. Appl. Polym. Sci., 91 (2) 1030–1040 (2004)CrossRefGoogle Scholar
  15. 15.
    Pizzi, A, Stephanou, A, “Fast vs. Slow-Reacting Non-modified Tannin Extracts for Exterior Particleboard Adhesives.” Holz als Roh- und Werkstoff Eur. J. Wood Wood Ind., 52 (4) 218–222 (1994)CrossRefGoogle Scholar
  16. 16.
    Arbenz, A, Avérous, L, “Chemical Modification of Tannins to Elaborate Aromatic Biobased Macromolecular Architectures.” Green Chem., 17 (5) 2626–2646 (2015)CrossRefGoogle Scholar
  17. 17.
    Bridson, JH, Derivatisation of Polyphenols. MSc thesis, University of Waikato, Hamilton, New Zealand (2007).
  18. 18.
    Bridson, JH, Grigsby, WJ, Main, L, “Synthesis and Characterization of Flavonoid Laurate Esters by Transesterification.” J. Appl. Polym. Sci., 129 (1) 181–186 (2013)CrossRefGoogle Scholar
  19. 19.
    Grigsby, WJ, Kadla, JF, “Evaluating Poly(lactic acid) Fiber Reinforcement with Modified Tannins.” Macromol. Mater. Eng., 299 (3) 368–378 (2014). CrossRefGoogle Scholar
  20. 20.
    Tolvaj, L, Mitsui, K, “Light Source Dependence of the Photodegradation of Wood.” J. Wood Sci., 51 (5) 468–473 (2005)CrossRefGoogle Scholar

Copyright information

© American Coatings Association 2018

Authors and Affiliations

  1. 1.Biopolymer Network Ltd and ScionRotoruaNew Zealand

Personalised recommendations