Preparation And Properties Of The Polyurethane/organic-montmorillonite Nanocomposites

Layered silicates/polymer nanocomposites have recently attracted a great deal of attention because of the improvements in the mechanical and thermal properties of the polymer. These improvements are brought about by having a small amount of layered silicates dispersed at the nanometer scale. In this article, we prepared the polyurethane/Organic-MMT nanocomposites based on toluene-2,4-diisocyanate(TDI) and glycerol polyoxypropylene ether (GPO3) as the raw materials, methylene-bis-orthochloroanilline (MOCA) as chain extender and acetone as solvent, by two-step polymerization. The nanocomposites were cured under room temperature.The tensile strength, elongation at break, anti-strength and hardness were measured by on a REGER Universal Testing System, DKZ-500 electric anti-fold instrument and LX-A instrument. The results showed that when the Organic-MMT content was 2 wt%, the nanocomposites had best anti-fold strength and tensile properties.The dispersion of the Organic-MMT was measured by X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM). The results indicate that the nanocomposites were intercalative materials and the dispersion of the Organic-MMT was very good when the organic-MMT content was ≤2 wt%.The thermal properties of the nanocomposites were measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the onset-degradation temperature of the nanocomposites was improved but the glass temperature of the nanocomposites were changed little.The apparent viscosity of the PU/ C16C18-MMT nanocomposite solutions which were primiparous just from the reactor, was measured by a NJ-79 Viscometer at 25°C. The apparent viscosities of the PU/C16C18-MMT in liquid state increase with increasing the C16C18-MMT in the PU/C16C18-MMT nanocomposites.Finally, we also prepared polyurethane/Oganic-MMT/SiO2 nanocomposites. It was found out that the nanocomposites have best mechanical properties when the content of the Oganic-MMT and SiO2 was 2 wt% and ratio of the oganic-MMT : SiO2 was 1: 4orWSiO2=0.8.