Impact of nanohybrid on the performance of non-reinforced biocomposites and glass-fiber reinforced biocomposites: Synthesis, mechanical properties, and fire behavior.

Biobased polymers are gaining increasing popularity particularly within key industries such as construction and building materials. However, glass fiber-reinforced polymer composites (GFRCs) based on biobased epoxy thermoset are inherently vulnerable against fire, producing huge fire hazards and eventually loss of structural integrity. In this work, a cobalt-based nanohybrid filler (CNH) was designed and synthesized to act as a high-performance synergist for biobased epoxy resin when combined with phosphorous flame retardants (FRs). An optimized formulation was found, resulting in a flame-retarded epoxy resin with a limiting oxygen index (LOI) value of 39.7 % and a V 0 rating in the vertical burning test. The GFRCs were then fabricated with optimized formulation. Interestingly, results showed that the percentage of peak heat release (PHRR) rate reduction was retarded from 74 % for the mixed resin to 36 % for GFRCs, potentially due to the interference of glass fiber. The optimized laminate with CNH showed improved mechanical properties at ambient temperature. Additionally, delayed time-to-failure values were found when sample coupons with CNH were subjected to a constant axial force loading while being ignited and burning, indicating higher resistance against fire for mechanical integrity. • Nanohybrid were first used for flame retarded fiber-reinforced biocomposites. • Interesting flame retardancy mode transfer was found from resin to composites. • Optimized laminate showed delayed failure time under simultaneous fire and load. [ABSTRACT FROM AUTHOR]