Abstract:

The glass transition temperature of ternary systems containing epoxy, PMMA grafted natural rubber and organic chemically modified montmorillonite (Cloisite 30B) were studied. Differential Scanning Calorimetry (DSC), Transmission Electron Microscopy (TEM), Infrared spectroscopy (FTIR) and Wide Angle X-ray Diffraction (WAXD) analysis were used. The following 4 materials were cured at 40°C for 20 h with and without postcuring at 125°C for 3 h. The samples were cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/cloisite 30B nanocomposites and cured toughened epoxy/cloisite 30B nanocomposites. Mixing process was performed by mechanical stirring. Poly (etheramine) was used as the curing agent. From the DSC analysis we found that the postcured samples possessed higher onset of glass transition temperature (T ). The presence of rubber can either increase or decrease the T of epoxy-rubber blend. The addition of 5 phr g g cloisite 30B, however, does not change the T , compared to the neat epoxy. The increase in T was observed g g for rubber toughened epoxy clay nanocomposite. The TEM images show the agglomeration of silicate and intercalated structure of silicate in binary and ternary nanocomposites. The WAXD results indicate the presence of crystalline structure in both unpostcured and postcured epoxy.