Enhanced flame retardancy and mechanical performance of PLA/PBAT composites by ionomer modified silica compatibilizer...

The flame retardancy and mechanical properties of polylactic acid (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) composites were significantly enhanced by incorporating ionomer-modified silica (IPU-SiO₂) as compatibilizer and microencapsulated ammonium polyphosphate (KH560@APP). The addition of 2 wt% IPU-SiO₂ facilitated interfacial compatibility of the two polymer phases. Meanwhile, the incorporation microencapsulated KH560@APP and IPU-SiO₂ effectively promoted char formation, enhanced barrier properties, and reduced the release of combustible volatiles. The synergistic effect of IPU-SiO₂ and KH560@APP led to a remarkable increase in the limiting oxygen index (LOI) to 29.9 %, achieving a UL-94 V-0 grade. The peak heat release rate (pHRR) and total heat release (THR) were reduced by 61.2 and 26.4 %, respectively, compared to the control sample. This combination not only enhanced flame retardancy but also improved the mechanical properties, with tensile toughness reaching 107.9 MJ/m³ and impact strength increasing by 33 % to 11.8 kJ/m². The enhanced interfacial bonding and the stable network formed by the fillers promoted better stress transfer and energy dissipation, leading to significant improvements in both strength and toughness.