Fire retardant coatings based on biomacromolecules: towards a sustainable approach

This work is aimed at describing the feasibility of the use of biomacromolecules (such as proteins and nucleic acids) as sustainable flame retardant coatings for textiles and also plastic materials. In fact, such compounds as caseins, hydrophobins, whey proteins and nucleic acids could represent a valuable potential alternative to the flame retardants (based on phosphorus or phosphorus/nitrogen compounds) currently available for textiles and plastic substrates. It is worthy to mention that some of the selected biomacromolecules are by-products deriving from the agro-food industry: in this context, their utilization as effective flame retardants could contribute to their further valorization. In addition, it is possible to overcome the problems related to the high cost of some of the selected biomacromolecules (such as nucleic acids) by recovering them from exhausted biomasses or vegetable scraps, using low environmental impact methods. Finally, the fireproof features provided by coatings based on these biomacromolecules are discussed, also taking into account the possible strategies for overcoming some of their current limitations.