Constructing a biomass flame retardant for fire-safe, thermal management, and compressive strength application of polybutylene adipate terephthalate/ polylactic acid foams

Poly (butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA) as a biodegradable thermoplastic material have been expected to replace traditional undegradable plastics. However, PBAT resins are highly flammable and have poor thermal stability and lower compressive strength performance. For enhancing PBAT compressive strength, thermal stability, and flame retardancy performance, polylactic acid (PLA) resin was used to mix with the PBAT matrix. Meanwhile, a biomass additive (PA@CS) was prepared through phytic acid (PA) solution as the grinding medium modifying cellulose (CS) particles by the ball milling process. As the PBAT/10PLA/PA@CS foam presented, PA@CS implanted into pore walls which supported the structure integrity of foams and presented the lowest surface temperature when heating at 170 °C for 180 s. The compressive strength of PBAT/10PLA/PA@CS foam with 5 wt% of PA@CS addition reached 1.05 MPa at 20 % strain. During the combustion process, PA@CS, as flame retardants, demonstrated excellent suppressing heat dispassion and fire-resistance performance. For instance, 5 wt% of PA@CS presented the highest ultimate oxygen index (LOI) (27.9 %), and UL-94 V-0 rating. In detail, 5 wt% of PA@CS also reduced the peak of heat release rate (PHRR) from 851.47 kW m⁻² to 524.45 kW m⁻² by 38 %, total heat release (THR) from 84.34 MJ m⁻² to 66.45 MJ m⁻² by 21 %. In this work, PA@CS as an efficient biomass flame retardant provided technical support for the development of high-performance compressive strength, thermal insulation, and flame retardancy PBAT/PLA foams.