摘要
Dual-crosslinked PVA/PEG films suppress PEG leakage via interpenetrating network. • Synergistic enhancement of mechanical strength and cycling reliability. • Maintained high phase-change enthalpy with reduced crosslinker content. • Effective as external thermal buffers for food temperature maintenance. Poly(ethylene glycol) (PEG), a widely used phase-change material, offers high latent heat but suffers from leakage during the solid-liquid transition. To address this issue, phase-change composite films were fabricated by solution casting using poly(vinyl alcohol) (PVA) as the matrix and PEG6000 as the energy storage component. Tetraethyl orthosilicate (TEOS) and formaldehyde were used as single crosslinkers, and a dual-crosslinking system combining both agents was further constructed. The effects of single and dual-crosslinking strategies on the overall film performance were systematically compared. TEOS formed an inorganic Si-O-Si network by sol-gel reaction, while formaldehyde constructed an organic network through acetalization with PVA hydroxyl groups. The combination of these two networks formed a complementary organic-inorganic dual-network structure, which restricted PEG chain mobility and enhanced the structural stability of the films. Compared with the uncrosslinked film, the tensile strength and elongation at break of the dual-crosslinked film increased by 60.2% and 122.1%, respectively. After 50 thermal cycles, it showed only a 1.4 J/g loss in phase-change enthalpy, while the leakage ratio remained below 7% after 50 heating-cooling cycles. Notably, this balanced mechanical and thermal performance was achieved with approximately 50% less crosslinker than that used in the single-crosslinked systems. These results demonstrate a low-crosslinker-content strategy for developing flexible external thermal-buffering layers for short-term food-temperature maintenance. Download: Download high-res image (331KB) Download: Download full-size image
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