The effect of expanded graphite/clay nanoparticles on thermal, rheological, and fire-retardant properties of poly(butylene succinate)

In this study, the effect of clay nanoparticles on the flame retardancy, thermal stability, thermal degradation kinetics and rheological properties of poly(butylene succinate) (PBS)/expanded graphite (EG) composites were investigated. The composites were prepared by melt blending, followed by melt compression. The results indicated that the presence of clay, improved the dispersion of the EG, as confirmed by exhibited significant increases in the rheological properties (storage modulus (G′), loss modulus (G″) and complex viscosity (η)) when compared to the pristine PBS. The presence of Cloisite 15 A organoclay, however, decreased the overall thermal stability of the composite material, due to its catalytic effect. The degradation kinetics revealed that the presence of EG can impede the clay's catalytic effect on the degradation process of PBS. Based on the comparison between PBS and PBS/EG composites, the flame retardancy improved after the addition of clay due to formation of char, which acted as barrier layer against heat, oxygen, and flammable gases.