Synergistic Effect Between Nano-Sb₂O₃ and Brominated Epoxy Resin on the Flame Retardancy of Poly(butylene terephthalate)

Abstract

Bromine antimony synergistic flame retardants had excellent flame retardancy and were widely used in the field of polymer flame retardancy. When the synergistic flame retardant antimony particles were reduced from micrometer to nanometer, the composite exhibited excellent comprehensive physical properties and flame retardancy. Nano-Sb2O3/BEO/PBT composites were prepared by melt blending method. The effects of nano-Sb2O3 and BEO content on the flame retardancy of composites were studied. The crystallization properties, thermal stability, mechanical properties, residue morphology and flame retardancy of nano-Sb2O3/BEO/PBT composite were analyzed, using DSC, TGA, SEM, coupled with EDX analysis, tensile test machine and flammability tests (LOI, UL94). The results showed that the thermal stability of PBT was improved when adding nano-Sb2O3. Moreover, the degree of crystallinity and tensile strength were improved, due to the superior dispersion and interfacial interactions between nano-Sb2O3 and PBT. But, the impact strength decreased gradually with the increase of BEO. At the same time, the limiting oxygen index and flame retardant grade were increased as the nano-Sb2O3 content increases. Meanwhile, residues SEM-EDX analysis indicated that more C elements were left, thus the charring layer of nanocomposites was compact. This showed that nano-Sb2O3 could promote solid phase flame retardancy of PBT matrix, improving thermal stability.