Improvement of acrylic-urethane paint adhesion to PP-EPDM surface by mediated electrochemical oxidation

Document Type : Article


Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran, Iran


Adhesion improvement of an acrylic-urethane paint on a bumper surface made from polypropylene/ethylene-propylene-diene monomer was investigated at long term after electrochemical treatment by 2N nitric acid and 0.6M Silver (II)-nitrate /2N nitric acid. The stability of the electrochemically treated samples was examined at different aging times by ATR and SEM. The results were also compared to those of the untreated and flame-treated samples. Accelerated UV weathering analysis along with morphology study by SEM approved the effectiveness of the Ag (II) treatment technique in long term particularly at curvature area of the bumper. For the Ag (II) treated samples, the increase in adhesion strength was sustained even after 650 hours exposure to UV irradiation in wet condition prior to bonding. In addition, the stability of the Ag (II)-treated surface was maintained for at least three months. In case of the flame-treated surface, hydrophobic recovery during aging in environment was found to reduce the polarity of the PP-EPDM surface. The pull-off test showed Ag (II) treatment can enhance adhesion strength of the acrylic-urethane coating on to PP-EPDM in comparison with the flaming method by 20.7%. Moreover the results of zeta potential analysis for Ag (II) treated blend showed a typical acidic surface.


1. Martinez, C. and Panizza, M. "Electrochemical oxidation of organic pollutants for waste watertreatment", Current Opinion in Electrochemistry, 11, pp. 62-67 (2018).
2. Nickerson, R. "Plasma surface modification for cleaning and adhesion", Polymers Laminations And Coatings Conference, pp. 1101-1108 (1998).
3. Brewis, D. and Dahm, R. "A review of electrochemical pretreatments of polymers", International Journal of Adhesion and Adhesives, 21(5), pp. 397-409 (2001).
4. Custodio, J., et al. "Activation of timber surfaces by flame and corona treatments to improve adhesion", International Journal of Adhesion and Adhesives, 29(2), pp. 167-172 (2009).
5. Farris, S., et al. "The fundamentals of  flame treatment for the surface activation of polyolefin polymers", Polymer, 51, pp. 3591-3605 (2010).
6. Fazeli, M., Florez, J.P., and Simao, R.A. "Improvement in adhesion of cellulose fibers to the thermoplastic starch matrix by plasma treatment modification", Composites Part B: Engineering, 163, pp. 207-216 (2019).
7. Fazeli, M. and Simao, R.A. "The effect of cellulose nanofibers on the properties of starch biopolymer", In Macromolecular Symposia, 380(1), pp. 1-8 (2018).
8. Buendia, J.J. and Fabregat, G. "Plasma-treated polyethylene as electrochemical mediator for enzymatic glucose sensors", Plasma Processes and Polymers, 15(1), pp. 1-10 (2018).
9. Cabrera, F., Dognani, G., Santos, R.J., et al. "Surface modification of natural rubber by sulfur hexa fluoride (SF6) plasma treatment: A new approach to improve mechanical and hydrophobic properties", Journal of Coating Science and Technology,3(3), pp. 116-120 (2016).
10. Williams, D.F. "Flame treatment of polypropylene: A study by electron and ion spectroscopies", International Journal of Adhesion and Adhesives, 63, pp. 26- 33 (2015).
11. Strobel, M. "A comparison of corona-treated and flame-treated polypropylene films", Plasmas and Polymers, 8(1), pp. 61-95 (2003).
12. Mokhtari, S., Mohammadi, F., and Nekoomanesh, M. "Mediated electrochemical degradation of polystyrene by silver (II): optimization and kinetic studies", International Journal of ChemTech Research, 5, pp. 2656- 2671 (2013).
13. Chashmejahanbin, M., Salimi, A., and Ershad Langroudi, A. "The study of the coating adhesion on PP surface modified in different plasma/acrylic acid solution", International Journal of Adhesion and Adhesives, 49, pp. 44-50 (2014).
14. Brewis, D., Briggs, D., Dahm, R., and Fletcher, A. "ToF-SIMS study of electrochemical pretreatments for polymers", Surface and Interface Analysis, 29(9), pp. 572-581 (2000).
15. Briggs, D., Brewis, D., Dahm, R., and Fletcher, I. "Analysis of the surface chemistry of oxidized polyethylene: comparison of XPS and ToF-SIMS", Surface and Interface Analysis, 35(2), pp. 156-167 (2003).
16. Brewis, D., Dahm, R., and Mathieson, I. "Electrochemical pretreatment of polymers with dilute nitric acid either alone or in the presence of silver ions", The Journal of Adhesion, 72(3), pp. 373-386 (2000).
17. Mokhtari, Sh., Mohammadi, F., and Nekoomanesh, M. "Surface modification of PP-EPDM used in automotive industry by mediated electrochemical oxidation", Iranian Polymer Journal, 25(4), pp. 309-320 (2016).
18. Ronagh-Baghbani, M., Naderi, G., and Mohammadi, F. "Mediated electrochemical oxidation of vulcanized polybutadiene/organoclay nanocompositecharacterization and kinetic study", Polymer Degradation and Stability, 131, pp. 30-41 (2016).
19. Mokhtari, Sh., Mohammadi, F., and Nekoomanesh, M. "Surface modification of vulcanized EPDM rubber by Ag (II): Kinetic study of Ag (II) generation and surface characterization", Scientia Iranica, 25(3), pp. 1371- 1383 (2018).
20. Ronagh-Baghbani, M., Naderi, G., and Mohammadi, F. "Surface characterization of polybutadiene and natural rubbers oxidized by silver (II)", Soft Materials, 14(3), pp. 187-198 (2016).
21. Mokhtari, Sh., Mohammadi, F., and Nekoomanesh, M. "Effect of process parameters on the concentration, current efficiency and energy consumption of electrogenerated silver (II)", Chemical Papers, 69(9), pp. 1219-1230 (2015).
22. Grundke, K., Jacobasch, H-J., Simon, F., and Schneider, S. "Physico-chemical properties of surfacemodi fied polymers", Journal of Adhesion Science and Technology, 9(3), pp. 327-350 (1995).
23. Basak, G.C. "Surface modification of argon/oxygen plasma treated vulcanized ethylene propylene diene polymethylene surfaces for improved adhesion with natural rubber", Applied Surface Science, 257(7), pp. 2891-2904 (2011).
24. Zeiler, T., Kellermann, S., and Munstedt, H. "Different surface treatments to improve the adhesion of polypropylene", Journal of Adhesion Science and Technology, 14(5), pp. 619-634 (2000).
25. Vogel, A.I., A Text-Book of Quantitative Inorganic Analysis-Theory and Practice, Chap. 2, pp. 89-116, Wiley (2013).
26. Newman, C.R. and Forciniti, D. "Modeling the ultraviolet photodegradation of rigid polyurethane foams", Industrial & Engineering Chemistry Research, 40(15), pp. 3346-3352 (2001).
27. Yousif, E. and Haddad, R., Photodegradation and Photostabilization of Polymers, Especially Polystyrene: Review, SpringerPlus, 2(1), pp. 398-430 (2013).
28. Rosu, D., Rosu, L., and Cascaval, C.N. "IR-change and yellowing of polyurethane as a result of UV irradiation", Polymer Degradation and Stability, 94(4), pp. 591-596 (2009).