Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE PVP directed CNTs network architecture governing damping conductivity and stretchability in natural rubber.

ABSTRACT
Achieving stable dispersion and multifunctional reinforcement of carbon nanotubes (CNTs) in nonpolar elastomer matrices remains a central challenge in the development of high-performance rubber composites. Herein, we propose a scalable aqueous dispersion and cocoagulation strategy to construct tunable CNTs networks within a natural rubber (NR) matrix, employing polyvinylpyrrolidone (PVP) as a dual-function dispersant and molecular bridging agent. Through systematic variation of PVP content at a fixed CNTs loading (3 phr), we reveal how the network architecture evolves from agglomerated clusters to semipercolated and densely bridged morphologies, enabling compositional control over mechanical strength, damping, toughness, and conductivity. A composition window of 1.2–1.8 phr PVP was identified to provide the most balanced mechanical and functional performance. Within this range, the CNR-4 (1.8 phr) sample exhibited an approximately 13% increase in tensile strength (21.1 MPa) relative to neat NR, while retaining about 75% of its original elongation (575% vs. 749%). At a slightly higher PVP content (2.4 phr, CNR-5), the composites achieved the highest thermal conductivity (0.185 W m−1 K−1), the lowest volume resistivity (1 × 109 Ω cm), and the flattest tanδ plateau (0.15–0.18 over 2–10 Hz), underscoring the continuity between mechanical optimization and network-mediated functional transport. A three-stage dissipation mechanism is proposed to interpret the network's frequency-dependent viscoelastic behavior, encompassing initial slippage, interfacial friction, and cyclic realignment. This work establishes a structure–function-application design framework based on dispersant-mediated network engineering. We introduce a tunable and scalable route to fabricate CNTs/NR composites with application-specific functionality. The principles demonstrated here offer broader utility for the design of adaptive, high-performance elastomers in transportation, electronics, and industrial damping systems.