Rosalba Fuentes-Ramírez

Significant advances are being made in the development of self‐healing polymers; however, most studies focus on thermally induced repair mechanisms or on encapsulating repair agents within the polymer matrix. This research explores a novel self‐healing hybrid polymer coating incorporating cerium oxide (CeONP) and zinc oxide (ZnONP) nanoparticles into a polymer matrix (with β‐cyclodextrin). The nanoparticles enhance the material's mechanical and self‐repairing properties. The nanoparticles, polymer matrix, and composites are characterized using XRD, SEM, XPS, and NMR techniques. Properties such as adhesion (5B adhesion for all systems), density, and contact angle are evaluated in accordance with ASTM standards. Shape recovery under UV light and the behavior of the composite are investigated after mechanical deformation and exposure to saturated NaCl medium. Notably, WPU containing 0.5% CeONP exhibits enhanced corrosion resistance, with electrochemical impedance increasing from 3.71 kΩ·cm ² post‐corrosion to 16.38 kΩ·cm ² after 3 h of UV treatment (the originally set value is 16.61 kΩ·cm ² , corresponding to 98.6% recovery). The self‐healing ability is evaluated under UV exposure, showing an impedance recovery of up to 80% in the presence of β‐cyclodextrin (β‐CD) and nanoparticles, attributed to hydrogen‐bonding interactions. This study presents UV‐induced self‐healing coatings with strong potential for durable, corrosion‐resistant industrial applications.

The synthesis and characterization of a hydrochar/CeO₂ composite along with its evaluation in methylene blue degradation under visible light are presented. The methodology consisted of a single-pass hydrothermal method, having as synthesis conditions 9 h of reaction time, 210 °C, autogenous pressure, and a biomass/CeO₂ ratio of 100:1. The composite characterization revealed good dispersion of CeO₂ in the carbonaceous matrix and significant synergy in the composite activation using visible irradiation. The photodegradation experiments showed an efficiency of 98% for white LED light, 91% for UV light, 96% for solar irradiation, and 85% for blue LED light using as conditions pH 7.0, 50 mg of composite, 50 mL of solution, 10 mg/L of dye initial concentration, and 120 min of contact time. Meanwhile, the reusability experiments evidenced a reuse capacity of up to five times with a constant photodegradation efficiency (99%); moreover, it was determined that the presence of electrolytes at pH below 7.0 during degradation negatively affected methylene blue degradation. Finally, the results of this work demonstrate that the hydrochar/CeO₂ composite can be synthesized by a green method and used for the efficient treatment of water contaminated with methylene blue.

Magnetic nanoparticles have been used to confer better properties to materials, particularly to polymers. Due the properties of the polymer, such as flexibility and lightness, combined, white nanoparticles provide other properties such as microhardness, corrosion resistance, among others. In this study, three types of nanoparticles were elaborated: magnetite, cobalt ferrite and nickel ferrite, through the coprecipitation method used in the elaboration of skin-like polyurethane (PU) -based composites. Specimens were made at different nanoparticle weights (0.1%, 0.3%, 0.5% and 1.0%). Likewise, the hardness was measured by means of a phase II Model PHT-2500 portable digital hardness tester and the tension tests were carried out on an Autograph Shimadzu universal machine. The stress results were plotted using the Jupyter Notebook for interpretation. Finding some improvements in the materials manufactured using the different ferrites already mentioned.

This work focused on the synthesis and characterization of composites, obtained based on polyacrylic acid and cellulose acetate, which incorporated graphite oxide and graphene oxide as structural reinforcement. The composites were obtained using the phase inversion method and the incorporation of the reinforcement, during the synthesis process, was carried out in proportions of 1% by weight. The characterization of the composites was carried out using IR, Raman, BET, SEM spectroscopy techniques and methods for determining acidic and basic sites. The results obtained showed that it is possible to synthesize composites that present a network configuration, made up of layers that give the material the effect of depth. Furthermore, it was possible to observe that both graphite oxide and graphene oxide were deposited on the outer edge of the hexagonal pores present in the material. Finally, the concentration values of acidic and basic sites were obtained. The presence of these sites could be associated with carboxylic groups inserted during the oxidation of graphitic materials and with non-reactive sites present in cellulose.

Due to continuous use and environmental factors (humidity and continuous exposure to the sun), the leather upholstery experiences cracking, discoloration and possible yellowing. The above factors significantly decrease the life of leather upholstery in cars. The objective of this work is to synthesize zinc oxide nanoparticles, which have optical properties that allow it to absorb UV radiation and then incorporate them into a polymeric matrix to develop a coating with UV protection for leather finishing in the automobile industry. The particles of zinc oxide were synthesized by the sol-gel method to obtain a nanometric particle size, the method represent a low-cost synthesis method, without the use of surfactants and easily scalable. With monoethylene glycol was formed a stable colloid with the zinc oxide nanoparticles and the polymer matrix. Finally, the final leather finishing obtained for the automotive industry has greater resistance to bending, also thermal stability was improved. In consequence, the lifetime of the leather finishing has improved.

At present there is great interest in the development of new nanomaterials that can be applied in different areas of study such as chemistry, physics, medicine, among others. In many polymeric materials, especially when used in coatings exposed to sunlight, they cause photolysis and photooxidation reactions, leading to the degradation of their physical-mechanical, optical and other properties. Therefore, the need to look for new materials capable of resisting radiation for prolonged periods, while retaining its original characteristics, such as hue and brightness, is imperative. Zinc oxide nanoparticles have attracted great interest in this aspect as they are used in most commercial sunscreens that use inorganic pigments, for their ability to adsorb ultraviolet rays. In the present work, the incorporation of the Np-ZnO in situ during the polymerization by the emulsion process of butyl acrylate was carried out. ZnO nanoparticles are incorporated into butyl polyacrylate in different concentrations of 0.3%, 0.5%, and 1% W, in which it is observed that at 1% there is greater agglomeration and in the others it does not affect the morphology of our polymer.