Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Hydrogels reinforced with OMCNT rheological studies.

ABSTRACT
The design of sustainable nanocomposite hydrogels with multifunctional properties is essential for enabling advanced applications in biomedical engineering, environmental remediation, and soft material technologies. In this study, a bio-based gum acacia–grafted polyacrylamide (GADMA) hydrogel reinforced with oxidized multiwalled carbon nanotubes (o-MWCNTs) was developed using a rapid and energy-efficient free-radical polymerization approach under microwave irradiation. Ammonium persulfate and N,N′-methylenebisacrylamide were employed as the initiator and crosslinker, respectively. Controlled incorporation of o-MWCNTs allowed systematic tuning of the hydrogel's electrical conductivity, mechanical strength, and viscoelastic behavior. The key novelty of this work lies in the synergistic combination of a naturally derived polysaccharide matrix with conductive nanofillers to produce a sustainable nanocomposite hydrogel exhibiting simultaneous enhancement in elasticity, thermal stability, crystallinity, and electrical conductivity features rarely achieved collectively in conventional hydrogels. Scanning electron microscopy confirmed uniform dispersion of o-MWCNTs within the polymer network, leading to reduced pore size and the formation of a compact and mechanically stable architecture. Rheological investigations revealed a substantially broadened linear viscoelastic region and a dominant elastic response (G′ > G″), with minimal viscous energy dissipation (tan δ < 1), indicating strong network integrity and enhanced load-bearing capability. Temperature-dependent measurements demonstrated structural stability up to approximately 40°C, while flow behavior analysis showed pronounced shear-thinning and non-Newtonian pseudoplastic characteristics, supporting improved processability and mechanical adaptability. Overall, this study introduces a sustainable and scalable fabrication strategy for multifunctional nanocomposite hydrogels. The developed GADMA/o-MWCNT system offers a unique balance of mechanical robustness, thermal durability, and electrical conductivity, making it a promising material platform for next-generation biomedical devices, soft electronics, energy storage applications, and environmental technologies.