Synergistic effect of different nanoparticles on flame retardant poly(lactic acid) with bridged DOPO derivative

摘要

This study aimed to examine synergistic effect of nanoparticles including nano silica (SiO2), organic montmorillonite (OMMT) and zinc borate (ZnB) on flame retardant poly(lactic acid) (PLA) composites containing a phenethyl-bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative (DiDOPO). 2% was the optimal addition content for these nanoparticles in PLA/DiDOPO composites, and nano SiO2 showed higher limiting oxygen index value (27.0%) than OMMT (25.8%) and ZnB (26.5%) at the same content. When compared with that of PLA/DiDOPO, the peak heat release rate was decreased dramatically after introducing nanoparticles, and the smoke was significant suppressed by adding SiO2. Among these nanoparticles, SiO2 had an obvious enhancement in the thermal stabilities of PLA composites both under nitrogen and air conditions resulting from its barrier effect. Moreover, a compact char was formed after combustion for PLA/DiDOPO/SiO2. In addition, high-resolution electron microscope and rheology results showed that SiO2 had a well dispersive quality in PLA/DiDOPO composites. Consequently, SiO2 shows the best synergistic effect with DiDOPO toward improving the flame retardancy of PLA. POLYM. COMPOS., 40:1043-1052, 2019. (c) 2018 Society of Plastics Engineers