Poly(diallyldimethylammonium chloride)/clay nanocomposites: effect of molecular weight and concentration of polymer on the structural, thermal, and dielectric properties

Poly(diallyldimethylammonium chloride), PDADMAC, with low and high molecular weight and with concentrations 0.5, 1, and 2 times the cation exchange capacity (CEC) of the clay was used to modify sodium bentonite clay to prepare hybrid PDADMAC/clay nanocomposites using solution-intercalation method. The prepared hybrids were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Data analysis showed that PDADMAC/clay nanocomposites have intercalated structure. The results showed also that the nanocomposite prepared using high molecular weight PDADMAC with concentration one times the CEC of the clay has the most intercalated structure and the highest thermal stability between the prepared nanocomposites. The room temperature dielectric properties were studied as a function of frequency in which the values of real (ε1) and imaginary (ε2) parts of relative permittivity are calculated and discussed. Higher values of ε1 and ε2 are obtained using PDADMAC with high molecular weight. Increasing the concentration of polymer affects the values of ε1 and ε2 towards lower values.