Skip to main content
Log in

Methanol degradation mechanisms and permeability phenomena in novolac epoxy and polyurethane coatings

  • Published:
Journal of Coatings Technology and Research Aims and scope Submit manuscript

Abstract

On a global scale, methanol is one of the most important feedstocks and is used widely as solvent and co-solvent. However, due to the polar nature and associated ability to conduct current, the small molecule can take part in galvanic corrosion of metal storage tanks and degrade the barrier properties of protective coatings. In the present work, we investigated the degradation of two novolac epoxy coatings and a polyurethane (PU) coating exposed to methanol with the aim of quantifying the various degradation paths. Absorption and desorption rates were measured and the thermomechanical properties followed by dynamic mechanical analysis. For evaluation of the coating barrier properties (i.e., breakthrough time and steady state permeation rates of methanol), permeation cells were applied. During methanol absorption, simultaneous leaching of certain coating ingredients and bonding of methanol to the binder matrix via hydrogen bonds was evidenced. In terms of classification, the bonding of methanol took place by two types of mechanisms. In Type I, the methanol molecule forms a single hydrogen bond to the coating network, thereby acting as a plasticizer, which decreases the coating storage modulus and glass transition temperature. For Type II bonding of methanol, on the other hand, two hydrogen bonds to the coating network form per molecule, resulting in so-called physical crosslinking. The Type I mechanism boosted segmental mobility and contributed to the leaching of the plasticizer benzyl alcohol from the novolac epoxy coatings and residual solvents (i.e., naphtha and xylene) from the PU coating. Following the methanol desorption, and attributed to an increased effective crosslinking density from Type II bound methanol, the novolac epoxy and PU coatings exhibited significant increases in the glass transition temperatures. In addition, for the three coatings, a gradual decline in the permeability rate of methanol was observed over time. These enhanced (and unexpected) barrier properties result from a combination of effects ascribed to Type II bound methanol and the leaching process.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Scheme 1
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

References

  1. Sørensen, PA, Kiil, S, Dam-Johansen, K, Weinell, CE, “Anticorrosive Coatings: a Review.” J. Coat. Technol. Res., 6 (2) 135–176 (2009)

    Article  Google Scholar 

  2. Møller, VB, Dam-Johansen, K, Frankær, SM, Kiil, S, “Acid-Resistant Organic Coatings for the Chemical Industry: a Review.” J. Coat. Technol. Res., 14 (2) 279–306 (2017)

    Article  Google Scholar 

  3. VanLandingham, MR, Eduljee, RF, Gillespie, JW, “Moisture Diffusion in Epoxy Systems.” J. Appl. Polym. Sci., 71 (5) 787–798 (1999)

    Article  CAS  Google Scholar 

  4. Marais, S, Metayer, M, Nguyen, TQ, Labbe, M, Saiter, JM, “Diffusion and Permeation of Water through Unsaturated Polyester Resins - Influence of Resin Curing.” Eur. Polym. J., 36 (3) 453–462 (2000)

    Article  CAS  Google Scholar 

  5. Nogueira, P, Ramírez, C, Torres, A, Abad, MJ, Cano, J, López, J, et al., “Effect of Water Sorption on the Structure and Mechanical Properties of an Epoxy Resin System.” J. Appl. Polym. Sci., 80 (1) 71–80 (2001)

    Article  CAS  Google Scholar 

  6. Han, SO, Drzal, LT, “Water Absorption Effects on Hydrophilic Polymer Matrix of Carboxyl Functionalized Glucose Resin and Epoxy Resin.” Eur. Polym. J., 39 (9) 1791–1799 (2003)

    Article  CAS  Google Scholar 

  7. Zhou, J, Lucas, JP, “Hygrothermal Effects of Epoxy Resin. Part I: the Nature of Water in Epoxy.” Polymer (Guildf), 40 (20) 5505–5512 (1999)

    Article  CAS  Google Scholar 

  8. Zhou, J, Lucas, JP, “Hygrothermal Effects of Epoxy Resin. Part II: Variations of Glass Transition Temperature.” Polymer (Guildf), 40 (20) 5513–5522 (1999)

    Article  CAS  Google Scholar 

  9. Barral, L, Cano, J, López, J, Nogueira, P, Ramírez, C, Abad, MJ, “Water Sorption in Tetrafunctional Phenol Novolac Epoxy Mixtures Cured with a Diamine.” J. Therm. Anal. Calorim., 52 (3) 823–830 (1998)

    Article  CAS  Google Scholar 

  10. Abeysinghe, HP, Edwards, W, Pritchard, G, Swampillai, GJ, “Degradation of Crosslinked Resins in Water and Electrolyte Solutions.” Polymer (Guildf), 23 (12) 1785–1790 (1982)

    Article  CAS  Google Scholar 

  11. El-Tantawy, F, “Influence of Solvent Transport on Physico-chemical Properties of Crosslinked Butyl Rubber Filled with TiC Ceramic.” Polym. Degrad. Stab., 73 (2) 289–299 (2001)

    Article  CAS  Google Scholar 

  12. Sonawala, SP, Spontak, RJ, “Degradation Kinetics of Glass-Reinforced Polyesters in Chemical Environments: Part II. Organic Solvents.” J. Mater. Sci., 31 (18) 4757–4765 (1996)

    Article  CAS  Google Scholar 

  13. Tsuda, K, “Behavior and Mechanisms of Degradation of Thermosetting Plastics in Liquid Environments.” J. Jpn. Pet. Inst., 50 (5) 240–248 (2007)

    Article  CAS  Google Scholar 

  14. Kaplan, ML, “Solvent Penetration in Cured Epoxy Networks.” Polym. Eng. Sci., 31 (10) 689–698 (1991)

    Article  CAS  Google Scholar 

  15. Dalena, F, Senatore, A, Marino, A, Gordano, A, Basile, M, Basile, A, “Methanol Production and Applications: an Overview.” In: Basile, A, Dalena, F (eds.) Methanol: Science and Engineering, pp. 3–28. Elsevier, Amsterdam (2018)

    Chapter  Google Scholar 

  16. (Website) Methanol Institute, “Atmospheric Above Ground Tank Storage of Methanol.” (2018). http://www.methanol.org/wp-content/uploads/2016/06/AtmosphericAboveGroundTankStorageMethanol-1.pdf (accessed 10 Jun 2020).

  17. Vesely, D, “Molecular Sorption Mechanism of Solvent Diffusion in Polymers.” Polymer (Guildf), 42 (9) 4417–4422 (2001)

    Article  CAS  Google Scholar 

  18. Kotnarowska, D, “Influence of Ultraviolet Radiation and Aggressive Media on Epoxy Coating Degradation.” Prog. Org. Coat., 37 (3) 149–159 (1999)

    Article  CAS  Google Scholar 

  19. Dang, W, Kubouchi, M, Yamamoto, S, Sembokuya, H, Tsuda, K, “An Approach to Chemical Recycling of Epoxy Resin Cured with Amine Using Nitric Acid.” Polymer (Guildf), 43 (10) 2953–2958 (2002)

    Article  CAS  Google Scholar 

  20. Feng, J, Berger, KR, Douglas, EP, “Water Vapor Transport in Liquid Crystalline and Non-liquid Crystalline Epoxies.” J. Mater. Sci., 39 (10) 3413–3423 (2004)

    Article  CAS  Google Scholar 

  21. Mitra, S, Ahire, A, Mallik, BP, “Investigation of Accelerated Aging Behaviour of High Performance Industrial Coatings by Dynamic Mechanical Analysis.” Prog. Org. Coat., 77 (11) 1816–1825 (2014)

    Article  CAS  Google Scholar 

  22. Gao, T, He, Z, Hihara, LH, Mehr, HS, Soucek, MD, “Outdoor Exposure and Accelerated Weathering of Polyurethane/Polysiloxane Hybrid Coatings.” Prog. Org. Coat., 130 44–57 (2019)

    Article  CAS  Google Scholar 

  23. Møller, VB, Wang, T, Dam-Johansen, K, Frankær, SM, Kiil, S, “Diffusion Cell Investigations into the Acidic Degradation of Organic Coatings.” J. Coat. Technol. Res., (2018). https://doi.org/10.1007/s11998-018-0094-z

    Article  Google Scholar 

  24. Sørensen, PA, Dam-Johansen, K, Weinell, CE, Kiil, S, “Cathodic Delamination: Quantification of Ionic Transport Rates Along Coating-Steel Interfaces.” Prog. Org. Coat., 67 (2) 107–115 (2010)

    Article  Google Scholar 

  25. Zhu, M, Vesely, D, “The Effect of Polymer Swelling and Resistance to Flow on Solvent Diffusion and Permeability.” Eur. Polym. J., 43 (10) 4503–4515 (2007)

    Article  CAS  Google Scholar 

  26. Guo, CJ, De Kee, D, Harrison, B, “Diffusion of Organic Solvents in Rubber Membranes Measured via a New Permeation Cell.” J. Appl. Polym. Sci., 56 (7) 823–829 (1995)

    Article  CAS  Google Scholar 

  27. Vesely, D, “Diffusion of Liquids in Polymers.” Int. Mater. Rev., 53 (5) 299–315 (2008)

    Article  CAS  Google Scholar 

  28. Wang, T, José, J, Graversen, E, Erik, C, Dam-Johansen, K, “Simultaneous Tracking of Hardness, Reactant Conversion, Solids Concentration, and Glass Transition Temperature in Thermoset Polyurethane Coatings.” J. Coat. Technol. Res., (2020). https://doi.org/10.1007/s11998-020-00407-3

    Article  Google Scholar 

  29. David, V, Grinberg, N, Moldoveanu, SC, “Long-Range Molecular Interactions Involved in the Retention Mechanisms of Liquid Chromatography.” In: Grushka, E, Grinberg, N (eds.) Advances in Chromatography. CRC Press, Boca Raton (2017)

    Google Scholar 

Download references

Acknowledgments

Financial support from the Hempel Foundation to CoaST (The Hempel Foundation Coatings Science and Technology Centre) is gratefully acknowledged.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Søren Kiil.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Wang, T., Luo, S., Wang, C. et al. Methanol degradation mechanisms and permeability phenomena in novolac epoxy and polyurethane coatings. J Coat Technol Res 18, 831–842 (2021). https://doi.org/10.1007/s11998-020-00446-w

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11998-020-00446-w

Keywords

Navigation