Flame retardancy of carboxylated polyhedral oligosilsesquioxane modified layered double hydroxide in the process of leather fatliquoring

Carboxyl polyhedral oligomeric silsesquioxane(P[POSS-MAA]) modified layered double hydroxides (LDHs) (P[POSS-MAA]-LDHs) was prepared by exfoliating and recombination method, which used P(POSS-MAA) and LDHs attracted each other through electrostatic force and hydrogen bond. The structure and morphology of P(POSS-MAA)-LDHs were characterized by X-ray diffraction and transmission electron microscope, which showed that LDHs was exfoliated and P(POSS-MAA) was on the surface of LDHs. Then it was introduced into the modified zanthoxylum bungeanum seed oil(MZBMSO) to obtain MZBMSO/P(POSS-MAA)-LDHs and applied it in leather fatliquoring process. The effect of the introduction of P(POSS-MAA)-LDHs on the flame retardancy, thermal stability, thermal insulation and smoke suppression of leather was investigated. Compared to the MZBMSO treated leather, the after flame time of MZBMSO/P(POSS-MAA)-LDHs treated leather decreased from 84 s to 32 s, and the limiting oxygen index increased from 23.1% to 27.5%, which exhibited improvement on flame retardancy of the leather. The temperature at 50% mass loss of MZBMSO/P(POSS-MAA)-LDHs treated leather increased from 375.1 to 408.3°C, which showed improvement on thermal stability of the leather. And the leather treated by MZBMSO/P(POSS-MAA)-LDHs had reduction of the total heat release and the total smoke production around 26.8% and 65.7%, respectively, which showed that MZBMSO/P(POSS-MAA)-LDHs treated leather had heat insulation and smoke suppression. Flame retardant mechanism of MZBMSO/(P(POSS-MAA)-LDHs) treated leather involved a combination of the gaseous phase and condensed phase flame retardancy. This work provided a new material for the flame retardant field and expanded the application range of polyhedral oligomeric silsesquioxane(POSS).