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<p>Polyethylene glycol (PEG)-based phase change materials (PCMs) suffer from severe molten leakage and intrinsically low thermal conductivity, which greatly restrict their practical applications. Herein, shape-stabilized PEG/epoxy resin (EP)/hexagonal boron nitride (hBN) composites were fabricated via a facile melt-blending and curing route, using EP as the supporting matrix and ball-milled hBN as the thermally conductive functional filler. First, the regulatory effect of PEG molecular weight (4000–20000) on the phase change behavior and anti-leakage performance of PEG/EP matrix (mass ratio 7:3) was systematically investigated, and the trade-off between energy storage density and shape stability under different molecular weights was clarified. The PEG6000/EP composite was identified as the optimal matrix, with a melting enthalpy of 159.78 ± 2.1&#xa0;J·g<sup>− 1</sup> and a melting peak temperature of 62.56&#xa0;°C. Subsequently, the influence of hBN content (10–50 wt%, relative to the total mass of PEG/EP blend) on the comprehensive properties of the composites was explored. Combined with differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), a plausible multi-scale regulation mechanism of hBN on phase change behavior, anti-leakage performance and thermal conductivity is tentatively proposed and discussed. Results show that hBN simultaneously improves the thermal conductivity and anti-leakage performance of the composites while maintaining acceptable phase change enthalpy, based on a hypothesized hierarchical mechanism involving potential intermolecular hydrogen bonding, crystal structure regulation, and inferred overlapping lamellar barrier pathways (tentatively regarded as a quasi-continuous three-dimensional functional network). At the optimal hBN loading of 40 wt% (relative to the PEG/EP blend, corresponding to 27.4 wt% in the final composite), the composite maintains a mass retention rate of 99.01% after 5&#xa0;h thermal exposure at 65&#xa0;°C, and its thermal conductivity is significantly enhanced, reaching 0.384 ± 0.015&#xa0;W·m<sup>− 1</sup>·K<sup>− 1</sup>, along with a melting enthalpy of 55.58 ± 1.3&#xa0;J·g<sup>− 1</sup>. These properties make the composite suitable for medium-to-low-temperature thermal energy storage scenarios. XRD and FTIR characterizations indicate that hBN may serve as a heterogeneous nucleation agent and interacts with the matrix through physical interactions such as possible hydrogen bonding (FTIR spectral shifts provide indirect evidence), with no evidence of new chemical bond formation observed. This work establishes a multi-scale structure-property relationship bridging intermolecular interactions and macroscopic performance, and provides a theoretical basis for the performance-balanced design of high-performance shape-stabilized PCMs.</p>

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Shape-stabilized polyethylene glycol/epoxy resin/hexagonal boron nitride phase change composites: Facile fabrication and simultaneous enhancement of anti-leakage performance and thermal conductivity

  • 期刊论文

  • 发表日期：

    2026年8月4日

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  • Dan Guo,
  • Jiaming Zhang,
  • Jianxin Zou

摘要

Polyethylene glycol (PEG)-based phase change materials (PCMs) suffer from severe molten leakage and intrinsically low thermal conductivity, which greatly restrict their practical applications. Herein, shape-stabilized PEG/epoxy resin (EP)/hexagonal boron nitride (hBN) composites were fabricated via a facile melt-blending and curing route, using EP as the supporting matrix and ball-milled hBN as the thermally conductive functional filler. First, the regulatory effect of PEG molecular weight (4000–20000) on the phase change behavior and anti-leakage performance of PEG/EP matrix (mass ratio 7:3) was systematically investigated, and the trade-off between energy storage density and shape stability under different molecular weights was clarified. The PEG6000/EP composite was identified as the optimal matrix, with a melting enthalpy of 159.78 ± 2.1 J·g− 1 and a melting peak temperature of 62.56 °C. Subsequently, the influence of hBN content (10–50 wt%, relative to the total mass of PEG/EP blend) on the comprehensive properties of the composites was explored. Combined with differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), a plausible multi-scale regulation mechanism of hBN on phase change behavior, anti-leakage performance and thermal conductivity is tentatively proposed and discussed. Results show that hBN simultaneously improves the thermal conductivity and anti-leakage performance of the composites while maintaining acceptable phase change enthalpy, based on a hypothesized hierarchical mechanism involving potential intermolecular hydrogen bonding, crystal structure regulation, and inferred overlapping lamellar barrier pathways (tentatively regarded as a quasi-continuous three-dimensional functional network). At the optimal hBN loading of 40 wt% (relative to the PEG/EP blend, corresponding to 27.4 wt% in the final composite), the composite maintains a mass retention rate of 99.01% after 5 h thermal exposure at 65 °C, and its thermal conductivity is significantly enhanced, reaching 0.384 ± 0.015 W·m− 1·K− 1, along with a melting enthalpy of 55.58 ± 1.3 J·g− 1. These properties make the composite suitable for medium-to-low-temperature thermal energy storage scenarios. XRD and FTIR characterizations indicate that hBN may serve as a heterogeneous nucleation agent and interacts with the matrix through physical interactions such as possible hydrogen bonding (FTIR spectral shifts provide indirect evidence), with no evidence of new chemical bond formation observed. This work establishes a multi-scale structure-property relationship bridging intermolecular interactions and macroscopic performance, and provides a theoretical basis for the performance-balanced design of high-performance shape-stabilized PCMs.