Dielectric Properties of Sustainable Poly(vinyl alcohol)/Chitosan Biocomposites Reinforced with Lemon Biowaste

Abstract

ABSTRACT Biocomposites based on poly(vinyl alcohol) (PVA) and chitosan (CS) reinforced with lemon peel powder (LPP) were systematically investigated to understand the effect of natural fillers on their dielectric behavior, with particular emphasis on interfacial relaxation dynamics and charge transport mechanisms. LPP, a biodegradable by‐product, was introduced at different loadings (1, 3, and 5 wt%) to enhance the functional properties of the PVA/CS blend while maintaining sustainability. Broadband dielectric spectroscopy, conducted over a wide temperature range (−40°C to 150°C) and frequency window (0.1 Hz–1 MHz), revealed four relaxation processes in the unfilled matrix: β‐relaxation, α‐relaxation, water polarization, and α c ‐relaxation. Upon LPP incorporation, an additional relaxation process emerged, which was identified using the electric loss modulus formalism and attributed to interfacial polarization between the polymer matrix and the filler. The Havriliak–Negami analysis, together with the study of relaxation dynamics, indicated improved interfacial compatibility with increasing LPP content. Furthermore, the temperature dependence of the frequency exponent “s” demonstrated that AC conduction in the composites follows the Correlated Barrier Hopping (CBH) mechanism, highlighting the role of the biowaste filler in tuning charge transport and polarization phenomena.