Prevention of TiO2 Crowding through Steric Hindrance by Silane Coupling in Organic Coatings

Document Type : Original Article

Authors

Chemical Engineering Department, Faculty of Engineering, Ege University, 35100 Bornova Izmir – Türkiye

Abstract

This study aimed to reduce TiO2 crowding through steric hindrance by grafting 3-methacryloxypropyltrimethoxysilane (MPS) onto the pigment surface. This was achieved using various TiO2/MPS mass ratios in dispersion formulations and characterized by FTIR and TGA analyses. Characterizations revealed the most efficient grafting for the TiO2/MPS ratio of 100/10 (labeled TT3). An optimum particle size of 250-350 nm for opacity was obtained after 30 minutes of TT3 dispersion, resulting in the maximum number density of 47.45 % within this size range. The TT3 dispersion demonstrated high lightness and opacity, with minimal changes in surface properties compared to untreated and other MPS-grafted TiO2 dispersions, suggesting its advantageous use. The impact of pigment volume concentration (PVC) on pigment spacing was examined using topcoats with PVC levels of 7, 11, and 13 %, incorporating TT3 and untreated TiO2 dispersions. The lightness and opacity results indicated that lower PVC levels allowed wider spacing between pigment particles in dry films. Additionally, untreated TiO2 pigments exhibited increased crowding at equivalent PVC levels compared to the TT3 dispersion, while a rise in PVC did not diminish opacity or lightness in dry films with TT3, highlighting the even pigment distribution. Notably, dry films of the topcoats with TT3 or untreated pigment dispersions revealed that the TT3-containing topcoat at 30 µm for a given PVC exhibited almost identical properties to those of the topcoat containing untreated TiO2 dispersion at 55 µm. Thus, MPS grafting facilitated reduced pigment usage in paint formulations and lower paint consumption per unit area, decreasing volatile organic compound emissions.

Keywords

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References

  1. Brock T, Groteklaes M, Mischke P. European coatings handbook. Hannover: Vincentz; 2000.
  2. Wicks Jr ZW, Jones FN, Pappas SP. Organic coatings: Science and technology. 3rd ed. Hoboken (NJ): Taylor & Francis; 2007.
  3. Diebold MP. Application of light scattering to coatings: A user's guide. London: Springer; 2014.
  4. Titanium dioxide for coatings [product overview]. The Chemours Company; 2019. Available from: https://www.tipure.com/en/-/media/files/tipure/legacy /titanium-dioxide-for-coatings.pdf
  5. Diebold MP, Monte Carlo A. determination of the effectiveness of nanoparticles as spacers for optimizing TiO2 opacity. J Coat Technol Res. 2011; 8(5): 541-552. doi:10.1007/s11998-011-9342-1
  6. Thiele ES, French RH. Light-scattering properties of representative, morphological rutile titania particles studied using a finite-element method. J Am Ceram Soc. 1998;81(3):469-479. doi:10.1111/j.1151-2916. 1998.tb02364.x.
  7. Löf D, Hamieau G, Zalich M, Ducher P, Kynde S, Midtgaard SR, et al. Dispersion state of TiO2 pigment particles studied by ultra-small-angle X-ray scattering revealing dependence on dispersant but limited change in drying of paint coating. Prog Org Coat. 2020; 142: 1-8. https://doi.org/10.1016/j.porgcoat.2020.105590.
  8. Lambourne R, Strivens TA. Paint and surface coatings: Theory and practice. 2nd ed. Cambridge: Woodhead Publishing Ltd; 1999.
  9. Uzunkavak O, Özdemir G. Design of dark-colored acrylic coatings for increased LiDAR detection in autonomous vehicles. Prog Org Coat. 2024; 196: 1-11. https://doi.org/10.1016/j.porgcoat.2024.108756.
  10. Yebra DM, Weinell CE. Key issues in the formulation of marine antifouling paints. In: Hellio C, Yebra DM. (eds.) Advances in marine antifouling coatings and technologies. Cambridge: Woodhead Publishing Ltd; 2009. 308-333.
  11. Tyler F. Tailoring TiO2 treatment chemistry to achieve desired performance properties [internet]. PCI Magazine; 2000. Available from: https://www.pcimag. com/articles/86202-tailoring-tio2-treatment-chemistry-to-achieve-desired-performance-properties.
  12. Buxbaum G, Pfaff G. Industrial inorganic pigments. 3rd ed. Weinheim: Wiley-VCH; 2005.
  13. Arkles B. Tailoring surfaces with silanes. Chem Tech. 1977; 7(12): 766-778.
  14. Plueddemann EP. Silane coupling agents. 2nd ed. New York: Plenum Press; 1991.
  15. Tesoro G, Wu Y. Silane coupling agents: The role of the organofunctional group. J Adhesion Sci Technol. 1991; 5(10): 771-784. https://doi.org/10.1163/15685 6191X00206.
  16. Sideridou ID, Karabela MM. Effect of the amount of 3-methacryloxypropyltrimethoxysilane coupling agent on physical properties of dental resin nanocomposites. Dent Mater. 2009; 25: 1315-1324. https://doi.org/10. 1016/ j.dental.2009.03.016.
  17. Siddiquey IA, Ukaji E, Furusawa T, Sato M. The effects of organic surface treatment by methacryloxy-propyltrimethoxysilane on the photostability of TiO2. Mater Chem Phys. 2007;105:162-168. https://doi. org/ 10.1016/j.matchemphys.2007.04.017.
  18. Sabzi M, Mirabedini SM, Zohuriaan-Mehr J, Atai M. Surface modification of TiO2 nanoparticles with silane coupling agents and investigation of its effect on the properties of polyurethane composite coating. Prog Org Coat. 2009; 65: 222-228. https://doi.org/10.1016/ j.porgcoat.2008.11.006
  19. Zhao J, Milanova M, Warmoeskerken MMCG, Dutschk V. Surface modification of TiO2 nano-particles with silane coupling agents. Colloids Surf A: Physicochem Eng Aspects. 2012;413:273-279. https://doi.org/10.1016/j.colsurfa.2011.11.033.
  20. A guidebook to particle size analysis [internet]. Horiba Instruments Inc.; 2012. Available from: https://ats-scientific.com/uploads/PSA_Guidebook.pdf
  21. International Organization for Standardization. ISO 7724-3. Paints and varnishes - Colorimetry - Part 3: Calculation of colour differences. Geneva: ISO; 1984.
  22. American Society for Testing and Materials. ASTM B117 – 19. Standard Practice for Operating Salt Spray (Fog) Apparatus. West Conshohocken (PA): ASTM International; 2019.
  23. American Society for Testing and Materials. ASTM D714-02. Standard Test Method for Evaluating Degree of Blistering of Paints. West Conshohocken (PA): ASTM International; 2017.
  24. Larkin PJ. IR and Raman spectroscopy: Principles and spectral interpretation. San Diego: Elsevier Inc.; 2011.
  25. Fei X, Cao L, Liu Y. Modified C.I. pigment red 170 with a core-shell structure: Preparation, characteri-zation and computational study. Dyes Pigm. 2016; 125: 192-200. https://doi.org/10.1016/j.dyepig.2015. 10.021.
  26. Florea NM, Lungu A, Vasile E, Iovu H. The influence of nanosilica functionalization on the properties of hybrid nanocomposites. High Perform Polym. 2012; 25(1): 61-69. https://doi.org/10.1177/ 0954008312455831.
  27. Liu Q, Ding J, Chambers DE, Debnath S, Wunder SL, Baran GR. Filler-coupling agent-matrix interactions in silica/polymethylmethacrylate composites. J Biomed Mater Res. 2001; 57(3): 384-393. https://doi.org/10.1002/1097-4636(20011205)57: 3%3C384::aid-jbm1181%3E3.0.co;2-f.
  28. Cheng Q, Li C, Pavlinek V, Saha P, Wang H. Surface-modified antibacterial TiO2/Ag+ nano-particles: Preparation and properties. Appl Surf Sci. 2006; 252(12): 4154-4160. https://doi.org/10.1016/ j.apsusc.2005.06.022.
  29. Diebold M, Kwoka R, Mukoda D. TiO2 scattering optimization and not-in-kind opacity alternatives. J Coatings Tech. 2013; 10(2): 30-35.
  30. Song GY, Jang I, Jeon SW, Ahn SH, Kim JY, Sa G. Controlling the surface properties of TiO2 for improvement of the photo-performance and color uniformity of the light-emitting diode devices. J Ind Eng Chem. 2021; 94:180-187. https://doi.org/10.1016/ j.jiec.2020.10.031.
  31. Lin JC, Heeschen W, Reffner J, Hook J. Three-dimensional characterization of pigment dispersion 
    in dried paint films using focused ion beam-scanning electron microscopy. Microsc Microanal. 2012; 18(2):266-271. https://doi.org/10.1017/S1431927611 012 44X.
  32. Yang F, Chen B, Hashimoto T, Zhang Y, Thompson G, Robinson I. Investigation of three-dimensional structure and pigment surrounding environment of a TiO2 containing waterborne paint. Materials. 2019; 12(3): 464-475. doi:10.3390/ma12030464

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