Table 8.

Flammability behavior of recently developed hybrid biocomposites.

Matrix	Fibers	Manufacturing Process	Flammability	Ref.
Novolac type Phenolic formaldehyde	PALF/kenaf Triethoxy (ethyl) silane treatment	Hot press	Phenolic resin formed a protective layer of char on the surface of composites. Combustion rates of the untreated hybrid composite were higher than the treated one.	[281]
Epoxy	Sisal/coir	Cold pressing	Increasing the fibers wt % increased flammability. This hybrid biocomposite was not suitable where the fire response is a serious consideration.	[275]
PLA	Banana fiber and nanoclay fillers (3 wt %)	Melt blending technique followed by injection molding Silane treatment	Improvement of thermal stability and fire retardancy by nanoclays that produced char as a thermal barrier to reduce combustion rate.	[311]
Cardanol	Kenaf fibers with recycled carbon filler Alkali treatment with 2% NaOH	Compression molding	Hybridization of kenaf fibers with recycled carbon filler improved the thermal stability and flammability property.	[312]
Epoxy	Banana short fiber and Al (OH)3 filler	Hand lay-up	Incorporation of Al (OH)3 particles reduced the rate of propagation of flame.	[313]
Polypropylene	Bamboo/glass	Compression molding	19% reduction of heat release rate and increase in the thermal stability.	[314]
Polypropylene	Biochar/wool fibers	Melt blending followed by injection molding	Improving fire resistance properties: 5 wt % wool fiber caused a delay in the onset of ignition and the time to reach peak heat release rate.	[287]
Polypropylene	Kenaf fibers with exfoliated graphite nanoplatelets	Melt extrusion	Graphene nanoplatelets improved the flame retardancy of composites: the fire performance index enhanced, the time to ignition prolonged, and the fire growth index reduced.	[315]
Epoxy Resin	pineapple/coir (1:1)	Hand lay-up	Layering pattern of coir/pineapple/coir (CPC) had higher resistance to burning.	[276]
High crystalline block copolymer polypropylene	Kenaf/wool with ammonium polyphosphate as a flame retardant and with ultraviolet ray stabilizer and colorant combination (UVC)	Thermal blending followed by injection molding	Reduction of sustained and forced combustion of the composite. Improvement of material response to the fire hazard.	[316]
Epoxy	Bamboo/kenaf/nanoclay Nanoclay types: halloysite nanotube (HNT), montmorillonite (MMT), and organically modified MMT (OMMT)	Hand lay-up	Flame retardancy improved with the loading of all types of nanoclay (OMMT was the best one). Improvement in flame properties in terms of peak heat release rate, total heat release, fire growth rate index, and the maximum average rate of heat emission and smoke growth rate.	[317]
Polyester	Banana peduncle fiber (BPF) with aluminum hydroxide (AH) particles Fiber treatment with vinyltriethoxysilane (VTS) and 3-aminoproply triethoxysilane (APTES) solutions	Hand lay-up	The addition of 10 wt % AH:10 wt % BPF to polyester composite retarded its burning. The ignition time and end of burning time delayed by 22.94% and 13.15%, respectively. The total heat release rate decreased by 29.68%.	[318]
Epoxy	Kenaf with nano oil palm empty fruit bunch (OPEFB) filler (3 wt %)	Hand lay-up	Hybrid nanocomposites presented better (and satisfactory) flame retardancy properties in comparison to kenaf/epoxy composites.	[319]
Epoxy	Arenga pinnata fiber (APF)/polyester yarn (PET)	Lay-up APF:PET ratio = 0:5, 20:5, 35:5 and 50:5 wt %	Mg(OH)2 as flame retardant. Hybrid composite of APF35/PET5/E55 with 5 wt % Mg(OH)2 exhibited a lower burning rate.	[236]
Ethylene propylene diene monomer (EPDM) rubber	Kevlar fiber (KF)/Nano-silica (NS)	Roll milling followed by compression molding	By increasing the KF loading, he flame retardant properties enhanced. Hybridization of KF and NS increased the TTI 1 noticeably.	[237]
PLA	Coir fiber (CF)/PALF Alkaline treatment of fibers	Internal mixer followed by compression molding CF:PALF ratios = 3:7, 1:1 and 7:3	Fibers loading: 30 wt %. C1P1 and C7P3 (CF:PALF = 7:3) exhibited higher thermal stability and char content.	[238]

¹ Time to ignition.