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<p>Post-harvest grain losses remain a major threat to food security, largely due to microcracking of hermetic sealing films under UV exposure and mechanical stress. The current study presents a UV-repairable multilayer hermetic sealing film incorporating microencapsulated methacrylate-functionalized polydimethylsiloxane (PDMS) as a healing agent within a high-density polyethylene (HDPE) matrix. The film comprises a HALS-stabilized outer HDPE layer, a microcapsule-loaded core layer, and an inner ethylene-vinyl alcohol (EVOH) gas-barrier layer. Upon crack formation, mechanical rupture of polyurethane microcapsules releases the low-viscosity PDMS healing agent, which rapidly fills the crack and polymerizes under ambient UV light (365&#xa0;nm, ≥ 50 mW/cm²), restoring both mechanical and barrier properties. Healing efficiency reached 92 ± 3% for tensile strength (cracks ≤ 50&#xa0;μm after 4&#xa0;h of UV) and ~ 88% for elongation at break, whereas cracks &gt; 100&#xa0;μm showed ~ 55% recovery under the same conditions. The healed film maintained excellent barrier performance with a water vapor transmission rate (WVTR) of 4.2 ± 0.3&#xa0;g/m²/day and an oxygen transmission rate (OTR) of 8.5 ± 0.7&#xa0;cm³/m²/day, well below the thresholds required for effective hermetic grain storage (WVTR &lt; 5&#xa0;g/m²/day, OTR &lt; 10&#xa0;cm³/m²/day). These properties remained stable over three damage–repair cycles. Accelerated aging tests (180 days at 85% RH and 40&#xa0;°C) confirmed high microcapsule stability (95% retention of the healing agent) and sustained UV resistance. In 12-month real-world validation using 1-ton maize storage bags, the self-healing film maintained oxygen levels &lt; 1%, prevented pest infestation (0% vs. 15–20% in controls), and limited moisture increase to 0.8% (2.5% in non-healing films). This UV-activated self-healing approach offers a practical and scalable solution that significantly extends the service life of hermetic grain storage systems while reducing post-harvest losses.</p> Graphical abstract <p></p>

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UV-repairable hermetic sealing films with microencapsulated siloxane healing agents for sustainable grain storage systems

  • 期刊论文

  • 发表日期：

    2026年7月13日

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  • Haroon,
  • Fawad Islam

摘要

Post-harvest grain losses remain a major threat to food security, largely due to microcracking of hermetic sealing films under UV exposure and mechanical stress. The current study presents a UV-repairable multilayer hermetic sealing film incorporating microencapsulated methacrylate-functionalized polydimethylsiloxane (PDMS) as a healing agent within a high-density polyethylene (HDPE) matrix. The film comprises a HALS-stabilized outer HDPE layer, a microcapsule-loaded core layer, and an inner ethylene-vinyl alcohol (EVOH) gas-barrier layer. Upon crack formation, mechanical rupture of polyurethane microcapsules releases the low-viscosity PDMS healing agent, which rapidly fills the crack and polymerizes under ambient UV light (365 nm, ≥ 50 mW/cm²), restoring both mechanical and barrier properties. Healing efficiency reached 92 ± 3% for tensile strength (cracks ≤ 50 μm after 4 h of UV) and ~ 88% for elongation at break, whereas cracks > 100 μm showed ~ 55% recovery under the same conditions. The healed film maintained excellent barrier performance with a water vapor transmission rate (WVTR) of 4.2 ± 0.3 g/m²/day and an oxygen transmission rate (OTR) of 8.5 ± 0.7 cm³/m²/day, well below the thresholds required for effective hermetic grain storage (WVTR < 5 g/m²/day, OTR < 10 cm³/m²/day). These properties remained stable over three damage–repair cycles. Accelerated aging tests (180 days at 85% RH and 40 °C) confirmed high microcapsule stability (95% retention of the healing agent) and sustained UV resistance. In 12-month real-world validation using 1-ton maize storage bags, the self-healing film maintained oxygen levels < 1%, prevented pest infestation (0% vs. 15–20% in controls), and limited moisture increase to 0.8% (2.5% in non-healing films). This UV-activated self-healing approach offers a practical and scalable solution that significantly extends the service life of hermetic grain storage systems while reducing post-harvest losses.

Graphical abstract