Flexural modulus, polymer clay

The procedure to obtain nanocomposites based on unsaturated polyester resins leads to improvements in the order of 120% in the flexural modulus, 14% in flexural strength and 57% increase in tensile modulus with 4.7% of clay slurry content. Thermal stability augments and the gelation temperature increases to 45 °C, as compared to that of the resin (Fig. 31.6). It seems that adding water to the MMT allows better intercalation of polymer chains into the interlamellar space. Because clay is first suspended in water, this improves dispersion and distribution of the particles in the resin matrix. Longer gelation times lead to more uniform and mechanically stronger structures and to yield stresses (Fig. 31.7). Enhanced polymer-clay interactions are revealed by XPS in this case (Fig. 31.8). 

The highest heat distortion temperature of 400°C flexural modulus (1.1 x 10 psi) and flexural strength (30,000 psi) of polyimide-montmorillonite clay nanocomposites made this polymer composite outstanding. 

With up to 40% clay, the compatibilized polymer/clay composites exhibit lower water vapor permeability than typical unfilled polyethylene. The compatibilized composites containing the clay particles were crosslinked, with the anhydride-grafted polyethylene bonded to the clay particles and uncrosslinked polyethylene. The composites exhibited improved flexural modulus, break strength, and notched Izod impact properties. 

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