Investigation Of New Composite Process And Properties For The Polyurethane/Montmorillonite Nanocomposites

In this dissertion, the novel composition process of Polyurethane/Montmorillonite (PU/MMT) nanocomposites and their properties were investigated respectively. The dissertion consists of two parts, one part dealed with the preparation, characterization and properties for the water based PU/MMT composites, another part concerned the effect of MMT content on the mechanical properties of PU/MMT elastomers.With assistant of ultrasonic, the novel water based PU nanocomposed resins exfoliated by cationic polyurethane polyelectrolyte, which suspends amount of the amine cations, were prepared. The characterization of the intercalative effect was performed by Fourier Transition Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Transition Electron Microscopy (TEM).The result of FTIR indicated that the band site of the stretching mode for the Si-0 bond shifted from 1037cm^-1 to the lower wavenumbers(1015cm^-1), the band site of the bending mode for the OH group attached on the Si atom shifted from the 915cm^-1 to 918cm^-1. The strong interaction between the MMT clay and the PU molecule was present. The images of the TEM showed that the cationic polyurethane polyelectrolyte had the better intercalative behavior. DSC data showed that the glass transition temperature of PU/MMT increased because of the presence of MMT solids, and the PU/MMT composite performed the better thermal stability than the pure PU. The result of TGA revealed that the strong interaction resulted the big increase in thermal stability improvement of the PU polymer.The PU/MMT composites were prepared by diisocyanate, polyol, OMMT and diamino-extender. With an increase in the content of OMMT, both the strength and elongation of PU/MMT composites increased. When the content of OMMT was at 6%, the strenth and tear stress reached the maxium, and then decreased. However the elongation increased monotonously. Compared with the pure PU elastomer, the strength of PU/MMT composite with 6wt% of OMMT increased by 78%, and the elongation of the PU/MMT composite increased by 113%.