Functionalized mannan carbamates for compostable high-moisture barrier coatings

Overview

This technology centers on functionalized mannose and oligomeric mannan carbamates derived from abundant plant polysaccharides. These biosourced materials serve as polymer building blocks for compostable skin coatings used on flexible packaging substrates such as cellophane, aluminum foil, and blends with PHA and PLA bioplastics. The carbamate chemistry enables tunable amphiphilic properties, allowing the materials to act as effective moisture barriers while remaining fully biodegradable under home composting conditions within five to eight weeks.

The value proposition addresses growing demand for sustainable packaging alternatives to synthetic polymer coatings. By converting low-value biomass and agricultural or industrial waste streams containing mannans into high-performance functional materials, the approach supports circular economy goals and reduces reliance on fossil-derived barrier films.

Technical specifications

Key features:

• Chemo-modification via carbamate chemistry applied to mono-, oligo-, and polysaccharides of mannan
• Thermoplastic behavior enabling extrusion processing below 150°C
• Exceptional flexibility for skin coating applications on cellophane, aluminum foil, and PHA/PLA blends
• Demonstrated water vapor transmission rates of 6 g/m²·24h at 38°C and 90% relative humidity on coated cellophane
• Projected tunability of WVTR down to 0.3 g/m²·day through modulation of degree of functionalization
• Compostable in home composting conditions with deconstruction occurring within a five-to-eight-week window
• Formulation compatibility with PHA and PLA bioplastics for multilayer coating structures

How it works:

Mannans extracted from softwood and agricultural or industrial residues are chemically modified through carbamate functionalization to adjust amphiphilicity and chain interactions. Enzymatically cleaved oligomeric mannans with a degree of polymerization between three and twenty are used to increase crystallinity, improving barrier performance while preserving compost-labile glycosidic bonds. The resulting carbamates can be co-extruded with conventional bioplastics to produce multilayer barrier films.

Technology readiness level

The technology has progressed through laboratory validation of chemical, thermal, rheological, film, and barrier properties. Biodegradability and compostability have been confirmed under home composting conditions. Coated substrates have been fabricated and characterized, with initial WVTR measurements establishing a performance baseline. The current proposal targets proof-of-concept work to optimize oligomeric mannan formulations and push barrier performance toward sub-0.3 g/m²·day targets, with formulation analysis planned for PHA, PLA, and mannan carbamate blends. The material is positioned for scale-up and pilot demonstration with industry partners in flexible packaging and barrier film applications.