Recent Advances in Bio-Based Additive Flame Retardants for Thermosetting Resins

Abstract

Thermosetting resins are used in many applications due to their great mechanical properties, chemical resistance, and dimensional stability. However, the flammability of thermosets needs to be improved to minimize fire risk and meet fire safety regulations. Some commercially available flame retardants have an adverse effect on people’s health and the environment. Thus, the development of novel, more sustainable flame retardants obtained or derived from biomass has become an objective of contemporary research. The objective of this study is to summarize recent progress on bio-based flame retardants for thermosetting resins so as to promote their prompt development. Groups of biomass compounds with a potential for flame retardant industrial applications were introduced, and their thermal degradation was investigated. The authors focused mostly on the thermal degradation of composites containing bio-based flame retardants determined by thermogravimetric analysis, their tendency to sustain a flame determined by a limiting oxygen index, and fire behavior determined by a cone calorimeter test. The results showed that the mode of action is mostly based on the forming of the char layer. However, in many cases, there is still a necessity to input a high amount of additive to achieve significant flame retardancy effects, which may adversely impact mechanical properties.

Strategies towards Fully Recyclable Commercial Epoxy Resins: Diels–Alder Structures in Sustainable Composites

“…Among thermosets, epoxy resins have shown to be one of the most promising structural materials [ 12 ], with growth exceeding 6% from 2021 to 2028 thanks to their efficient contribution to the green transition as light materials with high mechanical properties that are helping industries to reduce GHG emissions. In addition, comprehending the chemistry that underlies the resin’s structure has allowed us to adapt the material’s structure to meet the requirements of different processes while enhancing their characteristics [ 13 ] and application in potential sectors. Nevertheless, these thermoset polymeric structures cannot be efficiently recycled as their tridimensional stability does not allow for their reprocessability, and most of the materials are recycled by pyrolysis processes or landfilled.…”

Achieving superior fire safety for TPU 3D‐printed workpiece with EP/PBz/PDMS coating

“…Fire not only destroys material property, causes disruption of social order and ecological balance, but also endangers lives directly or indirectly. Of these, many big fires were caused by the combustion of polymeric materials 1 . In view of the flammability of polymers, the improvement of their combustion behavior is urgent and necessary so as to diminish fire hazards 2 …”

“…Of these, many big fires were caused by the combustion of polymeric materials. 1 In view of the flammability of polymers, the improvement of their combustion behavior is urgent and necessary so as to diminish fire hazards. 2 With the rapid development of the automotive industry, some automotive components are becoming more complex, precise, and personalized, making it difficult for traditional molding methods to achieve flexible production of automotive components with complex shapes and structures.…”

Chitosan as a Polyfunctional Crosslinker for a Renewable-Based Resorcinol Diglycidyl Ether

“…Sharif et al prepared chitosan-encapsulated graphene oxide to obtain diglycidyl ether of bisphenol A (DGEBA)-based nanocomposites with significant improvements in mechanical and thermal properties. In addition, chitosan was studied to achieve flame retardancy in thermosetting resins. − …”