Abstract

Cetyltrimethylammonium bromide (CTAB) and 3-aminopropyltriethoxy-silane (APTES) were used as modifiers to prepare a reactive and organophilic montmorillonite (O-MMT), then from this waterborne polyurethane (WPU)/O-MMT nanocomposite dispersions for leather flame retardant finishing were prepared through in-situ intercalation polymerization. Qualitative evidence of the presence of chemically-attached APTES on O-MMT is confirmed by FT-IR and an exfoliated structure of O-MMT in WPU matrix is confirmed by X-ray diffraction (XRD). The SEM analysis reveals that the O-MMT platelets are homogeneously dispersed throughout the polymer matrix when the O-MMT content is lower than 4wt%, whereas over 4wt%, inhomogeneous dispersion of the O-MMT platelets is observed. Performance study indicates that the incorporation of O-MMT, on one hand, is capable of enhancing the thermal stability and mechanical properties of WPU efficiently; on the other hand, enhancing the flame retardancy of finished leathers. From the analysis of vertical flame and oxygen index (OI) test, the nanocomposite with 4wt% O-MMT loading shows the optimum flame retardant effect, the OI value increases by 3.6 units.