Nanoscale size criterion for modifier selection in polymer composites for vibration damping

This study establishes quantitative criteria for evaluating the transition of dispersed particles to a nano-state in polymer composite systems. We demonstrate that the critical nanoparticle size L 0 = 230 θ D –1/2 [nm], where θ D is the Debye temperature, provides an adequate assessment of nanoscale characteristics across diverse material classes including metals, halides, and A III B V /A II B VI semiconductors. Experimental validation through thermally stimulated current spectroscopy and electron paramagnetic resonance reveals that particles below this dimensional threshold exhibit fundamentally different energy parameters, characterized by uncompensated charge states with extended relaxation times. Morphological analysis confirms that technological treatments – thermal (373-473 K), laser ( λ 0 = 1.06 μm, 2×10 –6 s pulse), and mechanochemical activation – substantially modify surface layer morphology, increasing the content of nanoscale constituents. The proposed dimensional criterion enables rational selection of modifiers for polymer-based composite materials with applications in vibration-damping components for automotive engineering. The validity of the proposed criterion is further confirmed by the analysis of thermal transport mechanisms in the formed interfacial layers. It is demonstrated that particles meeting the L 0 threshold promote the development of a three-dimensional physical bond network at the polymer-filler interface. This interfacial structuring not only enhances thermal conductivity but also facilitates the formation of viscoelastic layers with optimized mechanical energy dissipation ( t a n δ = 0.1-0.3), which is essential for vibration-damping components in mechanical systems.