Preparation and characterization of polymeric nanocomposite films for application as protective coatings

Abstract

Addiction of ceramic nanoparticles to acrylic polymers provides a simple and effective means to produce paints with important properties, such as mechanical resistance and tailored wettability, even though for optimal performances, an engineered nanoparticle distribution would be desirable. In this paper we report on the realization and on the morphological and functional characterization of nanocomposites where the nanophase is distributed on the surface of acrylic polymer films, in order to enhance the expression of surface-related properties. To this aim, commercial titanium oxide and silicon oxide nanopowders were dispersed in water and the suspensions were air-sprayed on polymeric films prepared by paint brushing, thus producing a nanostructured ceramic surface coating. Control of the pH of suspensions and acrylic acid functionalization of the surface of titania were used together with high power ultrasonic treatments in order to control dimension of the aggregates in the sprayed suspensions. Optical microscopy, mechanical profilometry, and atomic force microscopy were used to characterize the nanocomposite surface morphology and correlate it to the coating functional properties, evaluated through mechanical abrasion tests and contact angle measurements; also, colorimetry on coated stones was performed in order to test the impact of the coatings on the aesthetical appearance and their photostability under UV irradiation. Results show that the nanostructured ceramic layer slightly improves the resistance of coatings to mechanical abrasion in case of polymer films prepared from latexes. The nanocomposite surface layer does not affect the wettability of the polymer, which remained slightly hydrophilic; this behavior is likely due to inadequate distribution of the nanophase. On the other hand UV-induced superhydrophilicity was observed when the concentration of surface titania nanoparticles is about 0.6 mg/cm2. Colorimetric analysis on historical and Carrara marbles before and after coating evidenced the good transparency of the nanocomposites. Accelerated aging tests permitted to demonstrate that, on the historical marbles, the presence of the nanoparticles has a protective action against UV-induced damage of the underlying polymer film, preventing photodegradation

An effective polymer nanocomposite based on tetraethoxysilane (TEOS) and SiO2-Al2O3 nanoparticles for super protection of damaged ancient Egyptian wall paintings

“…Through reviewing previous studies, several nanoparticles such as SiO 2 , TiO 2 , CuO, MgO, Ca(OH) 2 , CaCO 3 and ZnO have been used to enhance the properties of broadly used polymers in the field of cultural heritage preservation (Marey Mahmoud and El-Midany, 2013; The current issue and full text archive of this journal is available on Emerald Insight at: https://www.emerald.com/insight/0369-9420.htm Al-Dosari et al, 2017;Kardar and Amini, 2019;David et al, 2020). Positively, using these nanoparticles improves the surface roughness, the photocatalytic behavior and the super hydrophobic/self-cleaning options (D'Amato et al, 2014;Gagliardi et al, 2017). As well, a discernible resistance to bioactivity was developed by a composite made of ZnO nanoparticles (van der Werf et al, 2015).…”

Effect Titanium Dioxide / Paraloid B.72 Nanocomposite Coating on Protection of Treated Cu-Zn Archaeological Alloys

“…Acrylic polymers affected by degradation through the activities of microbiological organisms. The biodegradation appeared when it used for a long-term protection of archaeological collections and outdoor monuments [18][19][20].…”

Waterborne Acrylate-Based Hybrid Coatings with Enhanced Resistance Properties on Stone Surfaces

“…The key parameters of hydrophobic surface are the low surface energy of the material and the texture of the geometrical micro-or nanostructure of the surface [17][18][19]. In the last two decades, the application of nanosized inorganic particles, incorporated or in situ formed inside a polymeric matrix [10,20], have been largely exploited in order to compensate for weaknesses and to develop a nanometric structure that promotes the development of waterborne coatings. Inorganic nanoparticles can impart the polymeric matrix with water-repellent, mechanical, thermal, electrical, optical, or adhesive properties, as well as add new functionalities useful for tailored applications [21][22][23][24][25].…”