Functional Materials from Waste Paper. V. Synthesis and Characterization of the Hybrid Nanocomposites of the Powder Celluloses Isolated from Waste Paper and Silver Nanoparticles

Objective: This study aimed to synthesize and characterize hybrid nanocomposites of powder celluloses (PCs) derived from waste newsprint and cardboard, incorporating silver nanoparticles. The focus was on the mechanism of nanoparticle formation and stabilization within the cellulose matrix during the reduction process. Methods: Hybrid nanocomposites were prepared using the diffusion-reduction method, with trisodium citrate serving as the reducing agent for silver salt solutions under heterogeneous conditions. The PC/silver molar ratio was varied from 20 to 40. Structural and morphological characterization of the nanocomposites was conducted using Fourier-transform infrared (FT-IR) spectroscopy, high-resolution solid-state ¹³C NMR spectroscopy, wide-angle X-ray scattering, scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDXA). Results and Discussion: The study demonstrated that silver nanoparticles with a spherical shape and sizes mostly below 100 nm formed on the PC surface. The silver content in the nanocomposites ranged from 1.2 to 7.3 wt %. Structural analysis revealed that the cellulose retained its crystalline modification (cellulose I) after the reaction. The cellulose matrix participated in a redox process during nanoparticle formation, leading to the establishment of new intermolecular bonds between the nanoparticles and the cellulose matrix. Conclusions: The developed method provides a simple and efficient approach for producing powder cellulose/silver nanocomposites with potential applications as antibacterial materials.