Biomacromolecules as novel green flame retardant systems for textiles: an overview

The field of flame retardancy of polymeric materials (i.e. plastics, foams and in particular textiles) is currently facing several changes and challenges, as some of the current halogenated or phosphorus-based flame retardants (FRs) have proven to be persistent, bioaccumulative, carcinogenic and/or toxic for animals and humans. Thus, the seeking for highly efficient green flame retardant products, exploitable by using simple and environmentally-friendly techniques (i.e. impregnation/exhaustion, layer-by-layer), is driving the research towards the development of worthy alternatives. In this context, very recently, biomacromolecules (in particular proteins and deoxyribonucleic acid) have been thoroughly investigated since they exhibit significant potentialities as novel green FRs for selected fabrics (cotton, polyester and their blends), as well as for bulk polymers (ethylene vinyl-acetate copolymers) and foamed polyurethane substrates. This work aims to review our recent results related to the “unconventional” use of these biomacromolecules as low-environmental impact FRs for fabric substrates, as well as the still open challenges and the perspectives that these products may offer in the forthcoming years in the field of flame retardancy for textiles. In order to provide the Reader with the basic knowledge necessary for understanding the role of biomacromolecules as FRs for textiles, first of all a description of the structure, main properties and conventional application of proteins and deoxyribonucleic acid will be given; the thermal and thermo-oxidative stability, the reaction to a flame exposure or to an irradiative heat source of selected fabrics – cotton, polyester and their blends – will be discussed, as well