Multiscale Simulation of Reactive Polymeric Systems With RMD and SPH Transport Modeling

Advancing polymeric materials requires understanding how molecular reactions couple with macroscopic transport during processing and service. This chapter reviews multiscale modeling of reactive polymer systems, focusing on coupling Reactive Molecular Dynamics (RMD) with Smoothed Particle Hydrodynamics (SPH). RMD resolves bond breaking, formation, and reaction kinetics, while SPH represents large-scale flow, heat transfer, and rheology. Their integration enables a unified framework for simulating polymerization, cross-linking, degradation, and flow-driven reactions under realistic conditions. Theoretical foundations and coupling strategies including domain decomposition, bridging-scale methods, adaptive resolution, and concurrent simulations are discussed. Applications such as reactive extrusion, phase separation, gelation, and pyrolysis highlight predictive capability. Key challenges remain in temporal coupling, reactivity transfer, force-field transferability, and reliable validation. Future directions include AI-enhanced coupling and quantum-informed reactive potentials.