Biodegradable PBS tie layer for improved moisture barrier in metalized films
A co-extrusion approach using polybutylene succinate (PBS) as a biodegradable tie layer to reduce microcracks in aluminum-based metalized films, enhancing moisture barrier performance for compostable food packaging applications.
Overview
This solution addresses a critical performance limitation in aluminum-based metalized films used for food packaging. Microcracks in the metal layer compromise the moisture barrier, reducing shelf life and product protection. The proposed approach introduces a biodegradable polybutylene succinate (PBS) tie layer between the metal layer and brittle core layers such as PLA. PBS serves two functions: shielding the aluminum from chemical attack by residual monomer in PLA and cushioning the metal film against mechanical stress caused by flexibility mismatches. Optional incorporation of superabsorbents such as silica gel into the PBS layer provides additional moisture management. The technology targets compostable and biodegradable packaging applications where high moisture barrier performance is essential.
Technical specifications
Core innovation:
- PBS tie layer with strain at break around 580 percent, suitable as a flexible skin or protective layer
- Co-extrusion process compatible with both blown and cast film extrusion
- Optional integration of superabsorbents (e.g., silica gel) within the PBS layer for enhanced moisture scavenging
- Multilayer laminate structure: compostable sealant-core film laminated to PBS layer and metalized
- Designed to protect aluminum metallization from hydrolyzed monomeric PLA components
Research capabilities available at Auburn University:
- Compounding capability for mixing superabsorbents in various polymers
- Cast film line with lamination capability
- Experience in plastic food packaging from the principal investigators
Technology readiness level
This concept is at an early stage and has not yet been validated. The proposed validation plan involves three stages: first, establishing baseline moisture vapor transmission rate (MVTR) of metalized PLA/PHA films under time and mechanical deformation; second, evaluating MVTR of metalized PBS films and developing a metallization process optimized for PBS; and third, laminating the standard compostable sealant-core film to a PBS layer, metalizing the structure, and measuring MVTR performance with and without moisture scavenger additives. The research team includes expertise from industry leaders in plastic packaging, positioning the project for practical translation toward compostable high-barrier packaging solutions.
About Auburn University
Auburn University is a comprehensive public land‑grant research university serving industry from its main campus in Auburn, Alabama. Companies engage through a research and technology park offering on‑site convening space and services, and via a Huntsville Research and Innovation Campus embedded in Cummings Research Park near Redstone Arsenal. A long‑standing cooperative education program and a statewide extension network link employers to student talent and field deployment across Alabama. Research is supported by competitive federal funding from agencies such as NSF, USDA, DoD, and NASA. The university’s Intellectual Property Exchange provides IP management, licensing, and commercialization support.
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