Halloysite Nanoclay Reinforced Biobased Polyurethane Nanocomposite Polymer Electrolyte

Developing polyurethane (PU) with enhanced physicochemical properties through cost-effectiveness and a sustainable approach is currently a significant challenge. This challenge aims to address the shortcomings of conventional options. In this study, a series of biobased PU nanocomposites derived from crop oil, incorporating natural halloysite clay nanotubes (HNTs) as filler, shows promising potential to reduce dependency on petroleum derivatives harness. A monoester polyol was prepared via the polyesterification of crop oil to prepare biobased PU nanocomposite polymeric films with different HNT content (0, 2, 4, 6, and 8 wt %). The obtained films were characterized by their chemical functional groups and interactions, morphology, thermal, mechanical, and electrochemical properties. Fourier transform infrared spectroscopy analysis confirmed the formation of urethane linkage in PU and the interaction between PU chains and HNTs. Scanning electron microscope showed well homogeneity and dispersion of HNTs. The presence of HNTs also affected the mobility of PU chains, a reduction in crystallinity and glass transition temperature (Tg) were confirmed by X-ray diffraction and differential scanning calorimetry, respectively. This was revealed also by the enhancement of thermal stability and mechanical properties compared to neat PU. At 6 wt % HNT, maximum tensile strength was 153% higher compared to neat PU while Young’s modulus increased by 443% than neat PU at 2 wt %. The key findings demonstrated that adding HNTs enhanced the estimated ionic conductivity and dielectric properties. Dielectric relaxation peaks with non-Debye relaxation behavior were observed for all samples. The highest electric and dielectric performance was recorded for the sample with 6 wt % of HNTs attributed to the well dispersion of the individual and partial agglomerates. These findings indicate a promising nanocomposite polymer electrolyte host with proper mechanical stability to withstand the electrode stack pressure and stresses caused by dimensional changes in the rechargeable batteries.