Simultaneous thermal analysis of cationic, nonionic and anionic polyacrylamide.

Polyacrylamide (PAM) and its derivatives are the most commercially available water-soluble polymers and are frequently used for the production of clay-polymer composites. The characterization of their thermal behavior and decomposition was carried out mainly under reduced conditions by using N, He or Ar gas flow. The object of this study was to investigate the thermal decomposition of cationic (PAMCl), nonionic (PAM°), and anionic (NaPAM) polyacrylamide under synthetic air (SynA) in detail using a thermogravimetry/differential scanning calorimetry (TG/DSC) system connected to a quadrupole mass spectrometer (MS).

Impact of Intrinsic Structural Properties on the Hydration of 2:1 Layer Silicates.

Several 2:1 layer silicates comprising di- and trioctahedral smectites of different layer charge between 0.2 and 0.4 per formula unit and a trioctahedral vermiculite were studied by an method that allowed Fourier transform infrared spectroscopy (FTIR) spectra and water vapor sorption isotherms to be obtained simultaneously.

Microscopic structure and properties of discrete water layer in Na-exchanged montmorillonite.

In this work, we focus on the atomic structure of the water interlayer of Na-exchanged montmorillonite. For two different surface charge densities, namely -0.086 and -0.

Low-frequency dielectric properties of three bentonites at different adsorbed water states.

Three bentonites of varying smectite content were investigated by dielectric spectroscopy in the frequency range 10(-4) to 10(6) Hz after storage at well-defined humidities. The identification of relaxation processes from complex permittivity measurements was difficult, since conductivity effects were superimposed on the underlying relaxations. Relaxation peaks revealed by the dissipation factor indicated the occurrence of interfacial processes between 10(2) and 10(6) Hz.

Correlation between the extent of catalytic activity and charge density of montmorillonites.

The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.