Mechanochemically covalently functionalized hexagonal boron nitride with proanthocyanidins for high-performance cellulose packaging toward fresh fruit preservation

Abstract Pristine cellulose paper is a biodegradable packaging material, yet it fails to regulate the internal microenvironment of fruit packages, lacking adequate antioxidant activity and sufficient gas/moisture barrier performance. Although hexagonal boron nitride ( h -BN) and proanthocyanidins (PACI) can individually modify cellulose, PACI tends to self-aggregate in pulp and h -BN sheets stack severely, hindering uniform dispersion. We employ solvent-free mechanochemical ball-milling to graft PACI onto exfoliated few-layer h -BN, yielding h -BN-g-PACI hybrid fillers with a high grafting ratio of 66.7%. Comprehensive characterizations confirm the formation of stable B-O-C covalent linkages. The composite paper, fabricated via standard paper-making, with 40 wt% filler loading exhibits uniformly dispersed fillers, resulting in a tensile strength of 70 MPa (2.33 times that of pristine paper) and thermal conductivity of 1.954 W/m·K (6.76 times), alongside superior UV-shielding, surface hydrophobicity, and DPPH radical-scavenging activity. Moreover, the composite paper demonstrates improved resistance to moisture permeation. Ambient storage tests on cherry tomatoes reveal that the paper synergistically moderates temperature fluctuations, blocks moisture escape, and inhibits oxidative degradation, significantly reducing fruit weight loss, soluble solids accumulation, and mold growth. This scalable, eco-friendly fabrication approach offers a biodegradable multifunctional cellulose material as a promising alternative to petroleum-based plastic films for fresh fruit preservation.