Ancient adhesives revisited: Unlocking potential for sustainable and renewable modern applications

Abstract

ABSTRACT Conventional petroleum-based adhesives present environmental challenges due to their toxicity, limited recyclability, and reliance on finite resources. Because ancient technology may serve as an inspiration for future solutions, the BiDebA (BioBased Debondable Adhesives) Interreg NWE project, systematically evaluated three archaeo-inspired bio-based adhesives –birch tar, rosin-beeswax blends and hide glue. The aim is to generate performance data relevant for future sustainable adhesive development. Natural additives used historically and in contemporary bio-based formulation research, including hematite and biochar, were incorporated to assess their influence on mechanical and thermal behaviour. A multi-analytical approach combining single lap-shear testing, thermal and rheological characterisation, and structural analysis was performed. The adhesives exhibited average lap shear strengths between 1.5 and 3.5 MPa, consistent with other light-duty bio-based systems. Birch tar showed the broadest substrate compatibility, including effective bonding to plywood and carbon-fibre composites, while rosin-beeswax blends and hide glue demonstrated material-specific strengths and limitations. Among the fillers tested, hematite provided the most consistent enhancements, improving mechanical strength and thermal stability while lowering debonding temperatures, particularly in birch tar and rosin-based systems. This identifies hematite as a dual-function additive capable of tuning performance while maintaining reversibility, supporting the development of repairable and recyclable bio-based adhesive systems. These findings highlight the value of archaeological adhesive technologies as informative material models rather than direct formulations. The dataset produced here also provides a scientific foundation for tailoring the mechanical and thermal behaviour of natural adhesives and supports ongoing efforts toward sustainable innovation in adhesive technology.