Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Green Synthesis of Silver Nanocomposites: Lawsonia inermis and Coriandrum sativum leaf extracts are employed as eco-friendly reducing agents for the synthesis of polyacrylic acid-based silver nanocomposites. A 2 mM AgNO3 solution is incorporated into the polymer system, followed by treatment with the respective plant extracts to form PAC-Ag NC and PAMH-Ag NC. The synthesized nanocomposites are subsequently subjected to comprehensive physicochemical characterization using microscopic, spectroscopic, and analytical techniques. Their antibacterial activity is then evaluated against representative Gram-positive and Gram-negative bacterial strains, demonstrating their potential as green antimicrobial nanocomposites.

ABSTRACT
Polymer-based nanocomposites are synthesized via green routes and attract significant attention for their sustainability and multifunctional performance. In the present study, polyacrylic acid (PAA), a non-toxic, water-soluble polymer, is used as a matrix for the green synthesis of silver nanocomposites, with plant extracts serving as reducing and stabilizing agents. Silver nanocomposites synthesized using coriander (Coriandrum sativum) leaf extract are denoted as PAC-Ag NC, while those prepared using Mehndi, commonly known as Henna (Lawsonia inermis) leaf extract, are termed PAMH-Ag NC. The nanocomposites are characterized using UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), ZETA potential, thermogravimetric analysis (TGA), and differential thermal analysis (DTA). XRD analysis confirms the formation of face-centered cubic (FCC) silver nanoparticles, with average crystallite sizes of approximately 13 nm for PAC-Ag NC and 88 nm for PAMH-Ag NC. SEM observations reveal a bamboo-like hierarchical morphology in PAC-Ag NC, attributed to shish-kebabs, suggesting improved structural integrity, whereas PAMH-Ag NC exhibits predominantly spherical nanoparticles. Thermal analyses show the nanocomposites remain stable up to about 200°C. Both nanocomposites display excellent antibacterial activity against Gram-positive and Gram-negative bacteria.