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

Purpose This contribution aims to introduce an effective low cost polymer-nanocomposite for possible application to achieve a super protection for highly damaged ancient Egyptian wall paintings. Design/methodology/approach SiO2 and Al2O3 nanoparticles were synthesized by the sol-gel method. Then, the polymer-nanocomposite was prepared by simple mixing and dispersing the nanoparticles into the tetraethoxysilane polymer solution, with the aid of an ultrasonic dismembrator. The application of the polymer-nanocomposite and other polymeric nanodispersions, on laboratory models, was performed by the brushing technique. Next, the materials stability was evaluated by means of digital optical microscope, colorimetry, FE-scanning electron microscope, measuring the static contact angle and water absorption rates. Findings The results were promising in creating a superhydrophobicity and the static contact angle (?S) measured for the polymer-nanocomposite reached 135o. An average of three measurements of the water absorption rate after polymer-nanocomposite treatment was 0.66 g/m2 s, compared to 2.60 g/m2 s for the control model (untreated). Further, an average of color difference (?E*) for the treated surface was 2.78, and after the accelerated thermal aging was 3.6. Observing the surface morphology, the polymer-nanocomposite enhanced the roughness of the treated surface and showed a high resistance to laboratory salt weathering. Practical implications Preparation of a polymer-nanocomposite by adding SiO2 and Al2O3 NPs to tetraethoxysilane polymer has been proposed. As a promising conservation material, the produced polymer-nanocomposite helped to form an efficient protective film. Originality/value This paper attains to develop an economic polymer-nanocomposite to maintain a high protection to damaged ancient Egyptian wall paintings and similar objects.