Abstract
<title>Abstract</title> <p>The rapid growth of the low-altitude economy has imposed stringent demands on packaging materials for transporting temperature-sensitive goods, requiring the integrated performance of thermal insulation, impact resistance, lightweight design, and sustainability, which conventional packaging materials struggle to achieve. Herein, a sustainable biocomposite is developed using cork bark as the primary raw material, simply bonded with polylactic acid (PLA), and further surface-bleached to construct a radiative cooling layer. Benefiting from the intrinsic closed-cell honeycomb structure of cork, the composite exhibits a low thermal conductivity of 0.080 W/(m·K). The bleached surface achieves a high visible reflectance of 88.3% and a mid-infrared emissivity of 96.2%, enabling all-day radiative cooling and delivering an interior-exterior temperature difference of up to 17.1 ℃. Moreover, the composite demonstrates a compressive strength of 3.51 MPa (approximately ten times that of expanded polystyrene), together with a high energy-absorption efficiency of 82.3%, excellent mechanical resilience with only 2.95% residual deformation after 50 compression cycles, outstanding dimensional stability upon water absorption with a volumetric expansion of 2.91%, and strong functional expandability. Life cycle assessment and economic analysis further confirm its environmental and economic advantages. This work provides a facile and green strategy for advanced sustainable packaging in low-altitude applications.</p>