Bio-based flame retardants to polymers: A review

Due to environmental concerns, some of the conventional halogenated flame retardants have been banned. In this context, both the industrial and academics have made efforts to develop more eco-friendly and sustainable flame retardant materials. Among new flame retardants, bio-based groups have attracted plenty of attention. In this review, varied types of bio-based flame retardants are systematically described, including the structural characteristics, flame retardant behaviors, and an over-view of flame retardant mechanism. Recent research progress on various bio-based materials such as flame retardants (e.g., chitosan, lignin, phytic acid, polydopamine, Tannic acid, b-cyclodextrin, etc.) applied to different polymers are adequately summarized. Finally, the opportunities and challenges for the future development of bio-based flame retardants are briefly outlooked.(c) 2022 Kingfa Scientific and Technological Co. Ltd. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).