Biological and technical materials for building structures need special properties to provide protection and security for their inhabitants. Especially resistance against the thermo-oxidative forces of fire limits the material selection. Actual solutions for increasing fire resistance are using low molecular, halogenated flame retardants especially in polymers. These additives are persistent and bio-accumulative, volatile and can migrate to the environment [1]. Additionally, the flame retardancy of these substances is enhanced by the use of Antimony(III)-oxide which is classified as potential cancerogenic for humans [2]. As a consequence, toxicologically less harmful and more environmentally friendly alternatives are needed.
Since the nests of social insects like wasps are also prone to fire in their habitats, they also require protection to enable the survival of their inhabitants. Thus, these problems may already have been “addressed” by evolution. Wasps are building their nests using a mixture of masticated wood particles and their saliva, which they can influence by the protein composition to change the properties of the paper like material [3]. Whether this is also influencing the flame resistance of their nests has not been investigated yet.
We investigated the fire behavior of different parts of the wasp nests and showed that their flammability is significantly reduced in comparison to synthetic papers. To reveal the incorporated flame retardant mechanisms, we produced biomimetic papers based on the same design principle as the wasp papers using wood particles from different tree species as well as different commercial proteins mimicking the main component of the saliva. The materials were flame tested and their thermal properties have been investigated using TG-FTIR in order to understand which component reduces the flammability.
We thereby aim for a fundamental characterization and evaluation of biogenic materials with regard to flame retardant properties in order to obtain more environmentally compatible flame retardant concepts and materials for technical applications in the long term.

References
[1] Q. Li, K. Yang, K. Li, X. Liu et al. Environmental Pollution 2017, 224, 679-688.
[2] S. Kemmlein, O. Hahn, O. Jann Environmental Research Programme of the Federal Ministry for Environment, Nature Conservation and Nuclear Safety, 2003.
[3] M.R. Cole, M.H. Hansell, C.J. Seath Insectes sociaux 2001, 48, 33–39.