Preparation and Characterization of a Cyclophosphamide-Core PAMAM Dendritic Montmorillonite

Polyamidoamine modified organo-montmorillonites (OMMT) bearing flame-retardant elements were prepared through montmorillonite (MMT) and polyamidoamines with different generations. These materials turned out to be a possible use for the flame-retardency of polymers. Different generations of dendrimers, G1.0, G2.0, and G3.0, were synthesized from a cyclotriphosphazene core. Characteristics of these dendrimers were studied by Fourier transform infrared (FTIR) spectroscopy, hydrogen nuclear magnetic resonance ( 1 H-NMR), ultraviolet (UV-Vis) spectroscopy, and intrinsic viscosity (IV). It was demonstrated that different generations of dendrimers had been well synthesized. These dendrimers were used as an organic intercalation agent to modify natural clay, Na + -MMT. Different generations of flame-retardant dendrimer modified OMMT, G1.0-OMMT, G2.0-OMMT, and G3.0-OMMT, were prepared. The interlayer spacing, thermal stability, and surface morphology of these dendritic MMTs were investigated by FTIR, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM) as well as energy dispersing spectrometry (EDS). It was seen that the thermal stability of G1.0-OMMT, G2.0-OMMT, and G3.0-OMMT was obviously improved with the increase of generations compared with that of MMT. In addition, an exfoliated structure existed in these dendrimer modified silicate layers.