Ciencias Exactas y Ciencias de la Salud

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Development and characterization of nanoparticle-based composites for fire-retardant cotton fabrics
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-12-03) Briones Baños, Michelle; Sánchez Rodríguez, Elvia Patricia; mtyahinojosa, emipsanchez; Murillo Hernández, José Alberto; Escuela de Ingeniería y Ciencias; Campus Estado de México; Almanza Arjona, Yara Cecilia
Cotton the most widely used natural textile fiber worldwide, but its high flammability posed a great safety concern, especially in occupational environments where workers remain vulnerable to fire-related injuries. There is a growing need for accessible, low-toxicity and effective flame-retardant solutions that can be applied to cotton. In this context, this study evaluates two environmentally conscious treatment routes: one based on chitosan and another based on citric acid combined with sodium hypophosphite (CA + SHP), and examines the effect of the incorporation of zinc oxide nanoparticles (ZnO NPs) into each system. ZnO NPs were synthesized by a typical reproducible precipitation method, producing high-purity, crystalline nanomaterials, confirmed by FTIR, Raman spectroscopy, and SEM. Both treatment systems were applied to cotton fabric without altering its color or dimensions. Chitosan introduced a slight increase in stiffness, while CA + SHP preserved the original softness. SEM confirmed that both coatings were deposited on the fiber surface but formed distinct morphologies, with chitosan generating films and CA + SHP producing localized deposits. Energy dispersive X-ray spectroscopy (EDS) revealed that ZnO NPs were deposited evenly throughout the fabric, without forming agglomerations. FTIR results indicated that the cellulose structure was unchanged after treatment, and XRD confirmed the predominantly amorphous nature of the chitosan films. Thermal analyses revealed that the treatments modified the decomposition behavior of cotton through different mechanisms. The chitosan–ZnO system shifted the main pyrolysis stage by 30 °C, indicating improved thermal stability, whereas the CA + SHP system reduced moisture sensitivity and generated a more thermally stable char residue. DSC supported these observations by showing reduced degradation peak intensities in all treated samples. The vertical flame test highlighted complementary fire-retardant behaviors. Chitosan-based formulations substantially reduced flame duration but produced weak char and long afterglow, whereas the CA + SHP system did not suppress flaming but strongly inhibited glowing combustion and produced short, cohesive char lengths. These differences demonstrate that the two formulations act at different stages of combustion: chitosan primarily affects flaming behavior, while CA + SHP reduces afterflame times. Overall, this work provides a comparative evaluation of two flame-retardant systems for cotton and identifies their respective strengths and limitations. The results suggest that combining their complementary mechanisms may enable more balanced, accessible, and effective fire-retardant treatments for protective clothing, with potential relevance for industries in regions where burn-related injuries remain a critical concern.
Optimization of nanocomposite hydrogels for the treatment of diabetic foot ulcers
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-11-24) Villalba Rodríguez, Angel Manuel; Iqbal, Hafiz Muhammad Nasir; RR/tolmquevedo; Escuela de Ingeniería y Ciencias; Campus Monterrey; Parra-Saldívar, Roberto
In the present, diabetic foot ulcers are a very common pathology all around the world, and most products in the market offer to solve a specific need for the patient such as battling infection or allowing wound debridement. In such regard biomaterial-based nano cues with multi-functional characteristics have been engineered with high interests around the globe. The ease in fine tunability with maintained compliance makes an array of nanocomposite biomaterials outstanding candidates for the biomedical sector of the modern world. In this context, the present work intends to tackle the necessity of alternatives for the treatment of diabetic foot ulcers through the formulation of nanoclay/polymer-based nanocomposite hydrogels. Laponite RD, a synthetic 2-Dimensional nanoclay that becomes inert when in physiological environment, while mixed with water, becomes a clear gel with interesting shear-thinning properties. Optimization of the hydrogel formulation is approached by preparing the samples at several concentration ratios (Nanoclay-Chitosan and Nanoclay-Gelatin; 35-95% of nanoclay in steps of 15%), where the mechanical properties such as viscosity, shear-thinning and injectability are observed to change. Zero shear viscosity of the samples was calculated by the Cross Model Equation, and was observed to increase for the chitosan samples as the nanoclay ratio increased (3.41x103 - 6.44x104 Pa⋅s at 35-65% of nanoclay, respectively) and then decreasing after that concentration of nanoclay. Gelatin had the opposite behavior, while both formulations having a zero shear viscosity of ~3.5x104 Pa⋅s at 95% of nanoclay. Injection force values of the samples in 3 mL plastic syringes with 20G needles, ranged between 1 and 4 N in average, approximately. Adding Laponite RD to chitosan or gelatin, allows for the modification of mechanical properties of such materials. The setup explored in this research allows for a promising polymeric matrix that can potentially be loaded with active compounds for antibacterial support in foot ulcers, as well as enzymes for wound debridement.

Ciencias Exactas y Ciencias de la Salud

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