Objective As a historical natural material, parchment paper has long been esteemed for its unique aesthetic appeal, distinctive texture, and inherent physical strength, reflecting centuries of traditional craftsmanship. Despite these qualities, its application in modern packaging is severely limited due to inadequate barrier properties and insufficient resistance to environmental factors such as moisture and oxygen. To overcome these constraints and bridge the gap between tradition and contemporary sustainability demands, this research focused on the modification of traditional parchment paper using advanced bio-based materials. The primary objective is to enhance its barrier functionality—specifically against water vapor and gases—while simultaneously improving its mechanical performance. Crucially, this modification process was designed to preserve the material’s eco-friendly nature and biodegradability. By integrating renewable biomaterials into the parchment paper structure, the study aims to transform a heritage medium into a high-performance packaging solution suitable for modern applications. Ultimately, this approach seeks to significantly expand the potential of parchment paper as a sustainable, high-functionality material in the evolving landscape of green packaging technologies.

Methods Dialdehyde carboxymethyl cellulose (DCMC) was synthesized through the controlled oxidation of carboxymethyl cellulose using sodium periodate as the oxidizing agent, introducing aldehyde groups with enhanced reactivity. Utilizing DCMC, along with gelatin and chitosan as key bio-based components, a ternary DCMC-gelatin-chitosan base solution was meticulously prepared. The formulation involved precise regulation of the mass ratio, pH level, and reaction temperature to ensure optimal compatibility and cross-linking potential. This functional solution was then applied to parchment paper via impregnation, enabling deep penetration and effective modification of the material’s internal structure. To evaluate the structural and morphological changes, the modified parchment paper was analyzed using scanning electron microscope (SEM) to observe surface topography, Fourier transform infrared spectroscopy (FTIR) to identify chemical interactions, elemental analysis to determine composition, and X-ray photoelectron spectroscopy (XPS) to examine surface chemistry. Physical performance was assessed using an electronic tensile tester and tear tester, while barrier properties were measured via gas and water vapor permeability testers. Environmental reliability was further investigated through yellowing and aging tests, moisture resistance evaluations, heavy metal migration assays, and accelerated oxidation experiments to simulate long-term stability under real-world conditions.

Results The optimal physical and barrier properties of the composite film were achieved when the mass ratio of DCMC-gelatin-chitosan was 1∶10∶1. Consequently, a base solution with this ratio was selected for parchment paper modification. The aldehyde groups of DCMC underwent Schiff base reactions with the amino groups of gelatin and chitosan within the base solution. Furthermore, the aldehyde groups formed covalent cross-linkages with amino groups present in the parchment paper itself. SEM analysis revealed that the impregnated parchment paper exhibited a smoother surface compared to the untreated sample. The modification successfully enhanced the parchment paper’s properties: tensile strength reached 16.60 kN/m; tearing index reached 10.47 mN·m²/g; water vapor permeability was 0.059 mg/(cm²·h); gas permeability was 5.98 mL/(cm²·h). Heavy metal migration was significantly below 1 mg/kg; yellowing resistance was rated 3-4; the moisture content of packaged salt after ten days was 0.21%; the total oxidation value after 7 days at 60 ℃ was 1.4. These results indicate a notable improvement in environmental reliability.

Conclusions Impregnation treatment with a DCMC-gelatin-chitosan base solution markedly could improve the physical strength, barrier effectiveness, and overall stability of parchment paper when exposed to complex environmental conditions. This modification technique can enhance the material’s durability, significantly reinforcing its resistance to tearing and stress. It also can greatly reduce permeability, thereby improving protection against water vapor and oxygen transmission. As a result, the treated parchment paper exhibited superior environmental reliability and longer functional life. These advancements highlight its broad application potential in sustainable packaging. The modified parchment paper shows great promise in meeting future market demands for high-strength, high-stability, and eco-friendly biomass-based materials, offering a viable alternative to conventional synthetic packaging solutions.