Flame retardance behaviour and degradation of plant-based natural fiber composites – A comprehensive review

Abstract

In recent times, a pertinent effort has been made by researchers to seek for biodegradable and environmentally friendly reinforcements to manufacture composite-based products. Carbon footprints and emissions of greenhouse gases have been considerably minimized by the increased use of biomaterials lately. Consequentially, reinforcement of natural fibers in polymer matrices is widely preferred owing to the striking of a remarkable balance between cost and performance and ease of processing. However, these materials have their limitations in terms of poor fire resistance and retarded flammability behaviour which restricts the use of natural fiber polymer composites widely in industrial sectors. The end-of-life conditions favour the use of natural fibers as potential reinforcements. Besides physical, chemical, and mechanical properties, the thermal properties of the composites must be given equal importance as they widen the application background of natural fiber polymer composites. Thermal properties are also important in structural applications which include the assessment of capability of a composite to transfer temperature from end to end, material behaviour, stability at elevated temperatures, and load-carrying capability at high temperatures. Degradation of composite materials is considered to be important during their service life as the composites will be subjected to various outdoor environmental conditions. All these parameters are important for any functional composite during its service life. After their use, the problem of disposal of these materials arises which ends up in various environmental hazards such as pollution and landfills. Hence, the assessment of biodegradability of green composites is also important which mostly happens with the action of microorganisms. Therefore, it could be deduced that the understanding of the flammability and degradation of biocomposites along with their testing methods is important for developing biocomposites with better fire-resistant, thermal degradation, and biodegradation characteristics. Hence, this review focuses on the flame retardance behaviour, thermal stability, and degradation of plant-based natural fiber polymer composites during and after their service life.