Modification And Property Of Inorganic Nanomaterials By Graftting With Pamam-based Dendrimer

Dendrimer is a class of perfect tree structure macromolecules with controlled surface functionality and size,highly branched and three-dimensional architecture,which has attracted a lot of scientific attention and provided a number of potential applications in the past decade. Polyamidoamine (PAMAM) dendrimer grafted nano-scale SiO2 improved the dispersibility of nano-particles in polymer-base composites and provided certain functionality.This study introduced a novel organic intercalation agent used for Montmorillonite (MMT) modification. The special agent involved three generations of dendrimer and dendron PAMAM-quatemary ammonium salts (S-QAS and HS-QAS based on PAMAM). This work studied the variation of the layer spacing of MMT with adjusting the generation or the feed of dendritic macromolecules and the different capacity of the intercalation agent by changing the charge or the generation. A novel theoretical model of intercalation was proposed to interpret the phenomena which appeared in the course of study. The organo-modified MMT (OMMT) and the Polystyrene (PS)/OMMT composites were characterized by X-ray diffraction (XRD), fourier transform infrared spectrometer (FTIR), transmission electron microscope (TEM), thermogravimetric analyzer (TG) and differential scanning calorimeter (DSC).The results show that the resulting layer spacing increased with the amount of G1-S-QAS in the intercalating process. Thus this study proposed a conceptual representation of conformations based on the variation of the layer spacing. The TEM pictures show that the modified OMMTs formed intercalation structure in the PS matrix, yet the unmodified MMTs still remained to be agglomeration. Though the hydrophobic molecules were introduced into the gallery, the strong Coulomb force and Van der Waals force were raised by the QAS molecules and prohibited the further intercalation or exfoliation. DSC curves show that the PAMAM-QAS were restricted by the layered silicates without sufficient free volume for molecular chain relaxation. TGA curves show that the Hoffman elimination of QAS in OMMTs begins at 170℃and 200℃, and the decomposition of the bulk PAMAM begins at higher temperature.Moreover , A series of poly(amidomine) dendrimers were sucessfully synthesized by divergent method using nanoscale silica as the core. In order to prepare dendrimer-grafed silica with a hydrophilic core and a hydrophobic shell, amino end-groups were terminated with benzaldehyde.The dendrtic skeleton and schiff-base structure were analyzed by FTIR and UV-vis spectra. Moreover, We investigated the hydrophilic and hydrophobic property of p, G3, S0, S1, S2 and S3. And We also discussed the adsorption properties to Cu2+ and antibacterial performance.The results showed that G3, S2 and S3 had great amphipathic property at the beginning of the precipitation test. It was interesting that the hydrophilic and hydrophobic property of G3, S2 and S3 were changed with time. G3 showed good hydrophilic property, however, S2 and S3 showed great hydrophobic property. And we also found that S3, G3 possessed the adsorption properties to Cu2+ and good antibacterial performance.