• International Journal of Technology (IJTech)
  • Vol 14, No 2 (2023)

Characterization and Application of TiO2/ZnO Nanoparticles as Pigments in Matt-Type Water-Based Paint

Characterization and Application of TiO2/ZnO Nanoparticles as Pigments in Matt-Type Water-Based Paint

Title: Characterization and Application of TiO2/ZnO Nanoparticles as Pigments in Matt-Type Water-Based Paint
Boy Isfa, Novesar Jamarun, Emriadi, Syukri Arief, Ahmad Hafizullah Ritonga, Denny Akbar Tanjung, Vivi Sisca

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Cite this article as:
Isfa, B., Jamarun, N., Emriadi, Arief, S., Ritonga, A.H., Tanjung, D.A., Sisca, V., 2023. Characterization and Application of TiO2/ZnO Nanoparticles as Pigments in Matt-Type Water-Based Paint. International Journal of Technology. Volume 14(2), pp. 320-329

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Boy Isfa Department of Chemistry, Universitas Andalas, Padang-25163, Indonesia
Novesar Jamarun Department of Chemistry, Universitas Andalas, Padang-25163, Indonesia
Emriadi Department of Chemistry, Universitas Andalas, Padang-25163, Indonesia
Syukri Arief Department of Chemistry, Universitas Andalas, Padang-25163, Indonesia
Ahmad Hafizullah Ritonga Institut Kesehatan Medistra Lubuk Pakam, Deli Serdang-20512, Indonesia
Denny Akbar Tanjung Faculty of Pharmacy, Institut Kesehatan Deli Husada Deli Tua, Deli Serdang-20355, Indonesia
Vivi Sisca Department of Biology Education, Universitas Merangin, Jambi-37313, Indonesia
Email to Corresponding Author

Abstract
Characterization and Application of TiO2/ZnO Nanoparticles as Pigments in Matt-Type Water-Based Paint

     This study investigates the characteristics of TiO2/ZnO nanoparticles and the application of TiO2/ZnO in matt-type water-based paint as a pigment. This study aims to determine the quality of TiO2-ZnO pigments in water-based paints in terms of whiteness, hiding power, dispersibility, and gloss. Matt-type water-based paint has been made by mixing water and additives substances in a high-speed mixer to result in a mill base paste, which is mixed with the pigment of TiO2/ZnO (25:75), CaCO3 filler, water, and additives, then filtered and mixed again with the C-817 binder. The characterization results showed that TiO2/ZnO nanoparticles contained TiO2 of 18.62% and ZnO of 77.49%, with an average particle diameter of 151.54 nm. TiO2/ZnO has a crystal size of 28.4 nm and a crystallinity degree of 72.3%. The application of TiO2/ZnO nanoparticles as a pigment in matt-type water-based paint resulted in good dispersion and hiding power and achieved whiteness of 82.2 and gloss at 60° of 2.00 better than TiO2 of 81.8 and gloss at 60° of 1.77.

Matt-type water-based paint; Pigment; TiO2; TiO2/ZnO; ZnO

Introduction

Paint is a complex mixture consisting of resins, pigments, solvents, fillers, and other additives used to coat the surface of a material to beautify, strengthen, or protect the material. There are two types of paint, namely water-based paint and solvent-based paint. Water-based paint commonly used is the matt type which gives an even and non-reflective finish. This matt water-based paint is the most popular choice because it is easy to apply on smooth interior surfaces. The matt-type application is generally used on ceilings and walls with an even finish and a sheen level of less than 10%, giving it a non-reflective appearance (Chen et al., 2022; Peruchi et al., 2021).

In the paint industry, the main white pigment popularly used is titanium dioxide (TiO2) because of its whiteness, high coverage, refractive index, covering power, achromatic force, good dispersion, and resistance to ultraviolet (UV) rays (Islam et al., 2020; Karakas and Çelik, 2018). These advantages have caused TiO2­ to be widely developed and researched and become the main choice in its application as a pigment compared to zinc oxide (ZnO), lithopone, and others (Gao et al., 2022; Costa et al., 2017). 

The TiO2 cannot be obtained naturally but is extracted from ilmenite ore. TiO2 can also be synthesized using the sol-gel method (Solanki et al., 2021; Yuwono et al., 2014), sonochemical (Rosales et al., 2021),  hydrothermal, solvothermal (Mamaghani, Haghighat, Lee, 2019; Sofyan et al., 2018, 2019), microwave (Li et al., 2021), co-precipitation (Bhogaita and Devaprakasam, 2021), and direct oxidation (Daraee et al., 2018). However, the synthesis of TiO2 is limited by the environmental pollution generated by industrial processes, the shortage of titanium resources, and the high selling price. Therefore, it is necessary to develop TiO2 by mixing it with other white pigments with better or almost similar quality to reduce the high demand for TiO2 nanoparticles (Razali et al., 2022 Isfa et al., 2022; Dell’Edera et al., 2021; George et al., 2021).

Zinc oxide (ZnO) is the main white pigment that has long been used in the organic paint industry because of its environmentally friendly nature. ZnO is naturally found in the form of the mineral zincite. The advantages of ZnO as a pigment are that it is stable against UV rays (does not change color), long lasts on both water-based and oil-based paints, and increases color retention. Compared with the other white pigments, ZnO has the least tendency to turn yellow (Papp et al., 2022; Ma et al., 2019; Adiwibowo, Ibadurrohman, Slamet, 2018). Based on the advantages of ZnO as a pigment, it is necessary to develop research related to ZnO combined with TiO2 to result in TiO2/ZnO nanoparticles and implement the use of matt-type water-based paints. The novelty in this work is related to the application of TiO2/ZnO mixtures as a pigment in matt-type water-based paints.

A few previous studies related to the development of TiO2/ZnO nanoparticles have been reported, including Miklecic et al. (2015), which studied the effect of TiO2/ZnO nanoparticles on the properties of waterborne polyacrylate coatings in outdoor conditions, where the existence of ZnO nanoparticles reduced coating flow time, increased pH, and decreased elongation. In contrast, the TiO2 increased the glass transition so that the combination of TiO2/ZnO increased color stability. El-Kader et al. (2021) observed morphological, structural, and antibacterial on TiO2/ZnO (50:50) nanocomposites from Hibiscus rosa-senensis extract, which produced an increase in the crystal size growth of ZnO with uneven distribution and irregular particle shape. It is different with the crystal size growth of TiO2 was inhibited the distribution particles and shape were evenly and uniform. Baudys et al. (2015) conducted a weathering test and photocatalytic activity on self-cleaning acrylic paint based on ZnO and TiO2, where the results showed that the paint sample TiO2-based pigment increased photoactivity during exposition on the QUV panel, while the paint sample ZnO-based ones showed a high initial photocatalytic activity but decreased during exposition in the QUV panel. Lv et al. (2019) studied radiation stability in solar reflective coatings using TiO2 and ZnO pigments, where the particle size affects the stability of the paint coating from radiation. Using TiO2/ZnO mixture as pigments in acrylic paints has achieved better photocatalytic activity than pure TiO2 and ZnO (Song et al., 2021; Jašková, Hochmannová, Vytrasova, 2013). The objective of this study is to characterize TiO2/ZnO nanoparticles and observe the quality improvement of TiO2/ZnO nanoparticles applied as pigments in matt-type water-based paints. 

Experimental Methods

2.1. Materials

    Titanium dioxide rutile (SR-2377) was obtained from Shandong Dongjia Group Co., Ltd. Shandong, China. Zinc oxide (ZnO) was supplied by Evergreen Chemical Factory Co., Ltd. Shaanxi, China. Calcium carbonate (Omyacarb-6 GD) as a filler was obtained from PT. Camco Omya Indonesia, Jakarta, Indonesia.

   The styrene-acrylic binder (C-817) and super-plasticizer (SPC) were received from PT. Inawan Chemtex Sukses Abadi, Jakarta, Indonesia. The optical brightener agent (OBA) was supplied by PT. Graha Jaya Chemical, Jakarta, Indonesia. Dispersing agents, anti-foaming agents, wetting agents, coalescent agents, antimicrobial agents (biocide), thickening agents, and ethylene glycol are used for commercial water-based paint recipes.

2.2. Nanoparticles Characterization

    The chemical composition of the pigments (TiO2, ZnO, and TiO2-ZnO) was analyzed by X-Ray Fluorescence (XRF) - PANalytical Epsilon 3. The pigments' crystal structure, size, and crystallinity degree were determined by X-Ray Diffraction (XRD) - PANalitycal X'Pert PRO MPD. Morphological of the pigments were characterized by Field Emission - Scanning Electron Microscope (FE-SEM) - FEI Inspect F50. The TiO2-ZnO (25:75) nanoparticle pigments characterized were made from a mixing process using a planetary mixer (KNS-60 LB).

2.3. Manufacturing Process of Matt-Type Water-Based Paint

    Water, thickening agent, wetting agent, dispersing agent, antimicrobial agent, anti-foaming agent, and ethylene glycol were added to a high-speed mixer according to Table 1, stirred using a zirconium ball mill at 2000 rpm for 1 hour, filtered with a sieve (mesh 200) and allowed to cool at room temperature. The results obtained are in the form of mill-base paste. The mill base paste, pigment (TiO2, ZnO, or TiO2-ZnO), optical brightener agent, super-plasticizer, CaCO3 filler, water, and coalescing agent were added into a high-speed mixer according to Table 1, stirred at 800 rpm for 30 min, filtered with a sieve (mesh 200), and dispersibility of the pigment was observed. Next, the C-817 binder was added and stirred at 100 rpm for 15 min. The results obtained are matt-type water-based paint with various pigments, referred to as a P sample (Karakas and Celik, 2018; Somtürk et al., 2016).

Table 1 Matt-type water-based paint recipes with various pigments

Figure 1 Preparation and application of TiO2/ZnO in matt-type water-based paint

2.4.  Application of Nanoparticles in Matt-Type Water-Based Paint

       Matt-type water-based paint is applied to the surface of the panel paper using a rod coating (100), allowed for 24 h, and the obtained result was visually observed the hiding power in panel paper. Next, whiteness and gloss were measured using a whiteness meter (BGD 585) and a gloss meter (BGD 516).

Results and Discussion

3.1. XRF Analysis of Pigments

     The results of XRF analysis on TiO2, ZnO, and TiO2/ZnO nanoparticles (Table 2) displayed that rutile had a TiO2 concentration of 94.57%. Zinc oxide nanoparticles had a ZnO concentration of 96.11%. In the TiO2-ZnO mixture, the concentration of TiO2 is 18.62%, and ZnO is 77.49%. These results indicate that the mixing of TiO2/ZnO with a composition of 25:75 showed no significant difference with the concentration of TiO2/ZnO in the mixture, which means that there is no chemical interaction. The concentration of TiO2 rutile was not significantly different from previous research (Sisca et al., 2021; Miklecic et al., 2015).

Table 2 Chemical Composition of TiO2, TiO2/ZnO, and ZnO


3.2.   XRD Analysis of Pigments

The crystallinity degree, size, and shape crystal of TiO2, TiO2/ZnO, and ZnO were analyzed by XRD. The XRD pattern is displayed in Figure 2. The characteristic peaks of TiO2 at 2 are 27.43°, 36.08°, 39.21°, 41.26°, 44.09°, 54.36°, 56.67°, 62.81°, 64.11°, 69.06°, 69.86°, 82.40°, and 89.63°. The peaks are suitable to the characteristic peak of rutile (01-087-0290), which has a crystallinity degree of 24.0 % and a crystal size of 29.8 nm with a tetragonal shape. This result also corresponds to previous reports (Razali et al., 2022; Daniyal, Akhtar, Azam, 2019).

The characteristic peaks of TiO2/ZnO at 2? are 27.41°, 31.74°, 34.40°, 36.23°, 44.00°, 47.54°, 54.33°, 56.61°, 62.87°, 66.40°, 67.99°, 69.10°, 72.47°, 76.99°, 89.62°, 92.71°, 95.34°, and 98.57°. The peaks are suitable to the characteristic peak of TiO2 rutile (01-072-4814) and zincite (03-065-3411), which has a crystallinity degree of 72.3 %, a crystal size of 28.4 nm with tetragonal and hexagonal shapes. This result corresponds to crystals of TiO2/ZnO (El-Kader et al., 2021; Mazabuel-Collazos, Gómez, Rodríguez-Páez, 2019).

The characteristic peaks of ZnO at 2are 31.70°, 34.36°, 36.19°, 47.49°, 56.56°, 62.83°, 66.37°, 67.92°, 69.05°, 72.58°, 76.90°, 81.43°, 89.61°, 92.65°, 95.24°, and 98.55°. The peaks are suitable to the characteristic peak of zincite (01-075-7917), which has a crystallinity degree of 64.1 % and a crystal size of 25.4 nm with a hexagonal shape. This result corresponds to previous reports (El-Kader et al., 2021).

In TiO2/ZnO pigment, there was a decrease in crystal size, which is not significantly different from TiO2 rutile, so TiO2/ZnO can achieve a good whiteness and is not significantly different when applied to water-based paint. The high crystallinity degree of TiO2/ZnO can increase the gloss of water-based paints compared to TiO2 pigments.

Figure 2 XRD of (a) TiO2; (b) TiO2/ZnO; and (c) ZnO

3.3.   SEM Analysis of Pigments

The morphological analysis results of nanoparticles using FE-SEM with a magnification of 10,000x (10 µm) and 100,000x (1 µm) (Figure 3) has displayed that all pigments have very small sizes (<200 nm), smooth, and uniform shapes (Mazabuel-Collazos, Gómez, Rodríguez-Páez, 2019; Karakas and Çelik, 2018; Mikle?i? et al., 2015).

The nanoparticle diameter distribution was measured using the ImageJ and originLab application based on the SEM image result (Figure 4). The nanoparticles diameter of TiO2 is 80.98 – 469.04 nm with an average of 182.07 nm, TiO2/ZnO is 67.61 – 446.20 nm with an average of 151.54 nm, and ZnO is 57.93 – 300.62 nm with an average of 127.96 nm. These results indicate that the diameter of the three pigments is smaller than that of a sieve (mesh 200) and suitable for use in the preparation of matt-type water-based paints because the pigments can be ensured that evenly distributed, which is indicated by the absence of pigments left on the sieve (El-Kader et al., 2021; Miklecic et al., 2015).

Figure 3 SEM Images of (a,d) TiO2; (b,e) TiO2/ZnO; and (c,f) ZnO

Figure 4 Diameter distribution of (a) TiO2; (b) TiO2/ZnO, and (c) ZnO

3.4.   Application of Nanoparticles as Pigments in Matt-Type Water-Based Paint Against Dispersibility, Hiding Power, Whiteness, and Gloss

Nanoparticles such as TiO2, TiO2/ZnO, and ZnO, used as pigments, have good dispersibility in water-based paints (Table 3). It refers to the result of the second filtering process, where no pigment particles are left in the sieve (Mesh 200), which indicates that the pigment particles have been evenly dispersed (no agglomeration occurs) (Karaka? and Çelik, 2018).
Table 3 The Whiteness, Gloss, Hiding Power, and Dispersibility of Matt-Type Water-Based Paints with Various Pigments

Recipe Name

Whiteness

Gloss

Hiding Power

Dispersibility

20° (95.1)

60°

(96.3)

85°

(99.7)

P1

81.80 + 0.10

1.13 + 0.06

1.77 + 0.06

4.60 + 0.10

Good*

Good**

P2

82.20 + 0.10

1.17 + 0.06

2.00 + 0.10

4.83 + 0.05

Good*

Good**

P3

79.63 + 0.15

1.13 + 0.07

1.93 + 0.06

6.57 + 0.15

Good*

Good**

P4

80.77 + 0.15

1.13 + 0.06

1.87 + 0.06

4.70 + 0.06

Medium*

Good**

Note:

*    Evaluation of hiding power results is carried out based on visual observations of the paint coating on panel paper, which refers to the standard color of white and black.

**   Evaluation of pigment dispersibility was carried out based on the number of nanoparticles left on the sieve (mesh 200), which were observed visually.

        Samples P2 and P3 have resulted in the same good hiding power quality as sample P1, which was evaluated by visual observation (Figure 5). While sample P4 resulted in a medium hiding power quality. These results indicate that TiO2/ZnO and TiO2/ZnO with the OBA and SPC are good for use as pigments.

Figure 5 A Hiding Power of (a) P1 (TiO2) & P2 (TiO2/ZnO); (b) P1 (TiO2) & P3 (TiO2/ZnO/OBA/SPC); and (c) P1 (TiO2) & P4 (ZnO/OBA)

    Based on the whiteness (Figure 6a), it is known that sample P2 has more good whiteness qualities than others. The whiteness percentage of sample P2 is 0.48% is higher than sample P1. While sample P3 has resulted in a whiteness percentage of 2.65%, which is lower than sample P1. These results indicate that TiO2/ZnO pigment has good whiteness. But, when the TiO2/ZnO is combined with OBA and SPC, it causes a decrease in whiteness (Karakas and Çelik, 2018).

Figure 6 (a) Whiteness and (b) Gloss of Water-Based Paint with Various Pigments

Reflection angles of 20° and 60° in sample P2 have resulted in better gloss values ??than other samples (Figure 6b), which is influenced by the high crystallinity degree of TiO2/ZnO nanoparticles. Meanwhile, at a reflection angle of 85°, sample P3 has resulted in a significant increase in the gloss value of 6.57, which was influenced by the presence of OBA and SPC in sample P3.

In terms of dispersibility, hiding power, whiteness, and gloss, it is known that sample P1 using TiO2/ZnO nanoparticles as a pigment has better quality than sample P1 when applied to matt-type water-based paint. The amount of pigment in water-based paint formulas commonly for the matt-type is 7-10%, semi-gloss is 20-25%, and gloss is above 35%. With a gloss value below 10%, the water-based paint was categorized as a matt-type.

Conclusion

The TiO2/ZnO nanoparticles have been successfully combined with the composition (25:75), which resulted in a crystallinity degree of 72.3%, a crystal size of 28.4 nm with tetragonal and hexagonal shapes. These nanoparticles contain 18.62% TiO2 and 77.49% ZnO compounds, with an average particle diameter of 151.54 nm. TiO2/ZnO nanoparticles also have been successfully applied as pigment to a matt-type water-based paint which achieved good dispersibility and hiding power and resulted in a whiteness of 0.48% and a gloss at 60° of 12.99% were better than TiO2. In the future, a TiO2/ZnO mixture will be made using a chemical method applied to a matt-type water-based paint with a composition according to the current works.

Acknowledgement

    The author would like to thank PT. Inawan Chemtex Sukses Abadi for the opportunity to conduct research and use the facilities in the Technical Department Laboratory.

References

Adiwibowo, M.T., Ibadurrohman, M., Slamet, 2018. Synthesis of ZnO nanoparticles and their nanofluid stability in the presence of a palm oil-based primary alkyl sulphate surfactant for detergent application. International Journal of Technology, Volume 9(2), pp. 307–316

Baudys, M., Krysa, J., Zlamal, M., Mills, A., 2015. Weathering tests of photocatalytic facade paints containing ZnO and TiO2. Chemical Engineering Journal, Volume 261, pp. 83–87

Bhogaita, M., Devaprakasam, D., 2021. Hybrid photoanode of TiO2-ZnO synthesized by co-precipitation route for dye-sensitized solar cell using phyllanthus reticulatas pigment sensitizer. Solar Energy, Volume 214, pp. 517–530

Chen, M.C., Koh, P.W., Ponnusamy, V.K., Lee, S.L., 2022. Titanium dioxide and other nanomaterials based antimicrobial additives in functional paints and coatings: review. Progress in Organic Coatings, Volume 163, p. 10666

Costa, J.R.C., Correia, C., Góis, J.R., Silva, S.M.C., Antunes, F.E., Moniz, J., Serra, A.C., Coelho, J.F.J., 2017. Efficient dispersion of TiO2 using tailor made poly(acrylic acid) -based block copolymers, and its incorporation in water based paint formulation. Progress in Organic Coatings, Volume 104, pp. 34–42

Daniyal, M., Akhtar, S., Azam, A., 2019. Effect of nano-TiO2 on the properties of cementitious composites under different exposure environments. Journal of Materials Research and Technology, Volume 8(6), pp. 6158–6172

Daraee, M., Baniadam, M., Rashidi, A., Maghrebi, M., 2018. Synthesis of TiO2-CNT hybrid nanocatalyst and its application in direct oxidation of H2S to S. Chemical Physics, Volume 511, pp. 7–19

Dell’Edera, M., Lo Porto, C., De Pasquale, I., Petronella, F., Curri, M.L., Agostiano, A., Comparelli, R., 2021. Photocatalytic TiO2-Based coatings for environmental applications. Catalysis Today, Volume 380, pp. 62–83

El-Kader, M.F.H.A., Elabbasy, M., Adeboye, A.A., Zeariya, M.G.M., Menazea, A.., 2021. Morphological, structural and antibacterial behavior of eco-friendly of ZnO/TiO2 nanocomposite synthesized via hibiscus rosa-sinensis extract. Journal of Materials Research and Technology, Volume 15, pp. 2213–2220

Gao, H., Yang, S., Mao, D., Long, M., Qu, X., 2022. Significant zinc release from widely-used commercial lithopone pigments under solar irradiation. Environmental Pollution, Volume 292, p. 118352

George, J., Gopalakrishnan, C.C., Manikuttan, P.K., Mukesh, K., Sreenish, S., 2021. Preparation of multi-purpose TiO2 pigment with improved properties for coating applications. Powder Technology, Volume 377, pp. 269–273

Isfa, B., Jamarun, N., Emriadi, Ritonga, A.H., Sisca, V., Faisal, H., Tanjung, D.A., 2022. Precipitated calcium carbonate/lithopone nanoparticles as substitution of TiO2 pigment for matte-type water-based paint. Rasayan Journal of Chemistry, Volume 15(4), pp. 2342–2349

Islam, M.T., Dominguez, A., Turley, R.S., Kim, H., Sultana, K.A., Shuvo, M., Alvarado-Tenorio, B., Montes, M.O., Lin, Y., Gardea-Torresdey, J., Noveron, J.C., 2020. Development of photocatalytic paint based on TiO2 and photopolymer resin for the degradation of organic pollutants in water. Science of The Total Environment, Volume 704, p. 135406

Jašková, V., Hochmannová, L., Vytrasová, J., 2013. TiO2 and ZnO nanoparticles in photocatalytic and hygienic coatings. International Journal of Photoenergy, Volume 2013.  pp. 1–6

Karakas, F., Çelik, M.S., 2018. Stabilization mechanism of main paint pigments. Progress in Organic Coatings. Elsevier Volume 123, pp. 292–298

Li, Q., Liu, Y., Wan, Z., Cao, H., Zhang, S., Zhou, Y., Ye, X., Liu, X., Zhang, D., 2021. Microwave-assisted synthesis of oxygen vacancy associated TiO2 for efficient photocatalytic nitrate reduction. Chinese Chemical Letters, Volume 33(8), pp. 38353841

Lv, J., Yang, J., Li, X., Chai, Z., 2019. Size dependent radiation-stability of ZnO and TiO2 particles. Dyes and Pigments, Volume 164, pp. 87–90

Mazabuel-Collazos, A., Gómez, C.D., Rodríguez-Páez, J.E., 2019. ZnO-TiO2 nanocomposites synthesized by wet-chemical route: study of their structural and optical properties. Materials Chemistry and Physics, Volume 222, pp. 230–245

Ma, J., An, W., Xu, Q., Fan, Q., Wang, Y., 2019. Antibacterial casein-based ZnO nanocomposite coatings with improved water resistance crafted via double in situ route. Progress in Organic Coatings, Volume 134, pp. 40–47

Mamaghani, A.H., Haghighat, F., Lee, C.-S., 2019. hydrothermal/solvothermal synthesis and treatment of TiO2 for photocatalytic degradation of air pollutants: preparation, characterization, properties, and performance. Chemosphere, Volume 219, pp. 804–825

Miklecic, J., Blagojevic, S.L., Petri?, M., Jirous-Rajkovic, V., 2015. Influence of TiO2 and ZnO nanoparticles on properties of waterborne polyacrylate coating exposed to outdoor conditions. Progress in Organic Coatings, Volume 89, pp. 67–74

Papp, I.Z., Alegría, A., Kónya, Z., Kukovecz, Á., 2022. Investigation into the effect of ZnO nanorod coating on the thermal-mechanical and dielectric properties of ITO coated PET. Materials Research Bulletin, Volume 149, p. 111701

Peruchi, R., Bartosiak, A., Zuchinali, F.F., Bernardin, A.M., 2021. Development of a water-based acrylic paint with resistance to efflorescence and test method to determine the appearance of stains. Journal of Building Engineering, Volume 35, p. 102005

Razali, M.N. Bin, Alkaf, A.A., Zuhan, M.K.N.B.M., 2022. formulation of water-based white colour paint from waste titanium dioxide. Materials Today: Proceedings, Volume 48(6), pp. 1905–1909

Rosales, A., Ortiz-Frade, L., Medina-Ramirez, I.E., Godínez, L.A., Esquivel, K., 2021. Self-cleaning of SiO2-TiO2 coating: effect of sonochemical synthetic parameters on the morphological, mechanical, and photocatalytic properties of the films. Ultrasonics Sonochemistry, Volume 73, p. 105483

Sisca, V., Deska, A., Syukri, S., Zilfa, Z., Jamarun, N., 2021. Synthesis and characterization of CaO limestone from lintau buo supported by TiO2 as a heterogeneous catalyst in the production of biodiesel. Indonesian Journal of Chemistry, Volume 21(4), pp. 979–989

Sofyan, N., Ridhova, A., Wu, J., Yuwono, A.H., 2018. Characteristics of nano rosette TiO2 hydrothermally grown on a glass substrate at different reaction time and acid concentration. International Journal of Technology, Volume 9(6), pp. 291–319

Sofyan, N., Ridhova, A., Yuwono, A.H., Sianturi, M.C., 2019. Effect of NaCl addition on nano rosette TiO2 crystal growth during hydrothermal deposition. International Journal of Technology, Volume 10(6), pp. 291–319

Solanki, K., Parmar, D., Savaliya, C., Kumar, S., Jethva, S., 2021. Surface morphology and optical properties of sol-gel synthesized TiO2 nanoparticles: Effect of Co, Pd and Ni-doping. Materials Today: Proceedings, Volume 50(part 6), pp. 25762580

Somturk, S.M., Emek, ?.Y., Senler, S., Eren, M., Kurt, S.Z., Orbay, M., 2016. Effect of wollastonite extender on the properties of exterior acrylic paints. Progress in organic coatings,. Elsevier Volume 93, pp. 34–40

Song, S. Song, H., Li, L., Wang, S., Chu, W., Peng, K., Meng, X., Wang, Q., Deng, B., Liu, Q., Wang, Q., Weng, Y., Hu, H., Lin, H., Kako, T., Ye, J., 2021. A selective Au-ZnO/TiO2 hybrid photocatalyst for oxidative coupling of methane to ethane with dioxygen. Nature Catalysis, Volume 4(12), pp. 1032–1042

Yuwono, A.H., Zhang, Y., Wang, J., 2014. Investigating the nanostructural evolution of TiO2 nanoparticles in the sol-gel derived TiO2-polymethyl methacrylate nanocomposites. International Journal of Technology, Volume 1(1), pp. 291–319