Interfacial polarization mode

In this study, both the normal mode relaxation of the siloxane network and the MWS processes arising from the interaction of the dispersed nanoclay platelets within the polymer network have been observed. Although it is routine practice to observe the primary alpha relaxation of a polymeric system at temperatures below Tg, in this work it is the MWS processes associated with the clay particles within the polymer matrix that are of interest. Therefore, all BDS analyses were conducted at 40°C over a frequency range of 10 to 6.5x10 Hz. At these temperatures, interfacial polarization effects dominate the dielectric response of the filled systems and although it is possible to resolve a normal mode relaxation of the polymer in the unfilled system (see Figure 2), MWS processes arising from the presence of the nanoclay mask this comparatively weak process. 

The cross-axis CPC produces a unique mode of planetary motion, such that the column holder rotates about its horizontal axis while revolving around the vertical axis of the centrifuge.This motion provides satisfactory retention of the stationary phase for viscous, low-interfacial tension, two-phase solvent systems, such as aqueous-aqueous polymer phase systems. Our previous studies demonstrated that the cross-axis CPC equipped with a pair of multiplayer coils or eccentric coil assemblies in the off-center position was very useful for the separation of proteins with polyethylene glycol-potassium phosphate solvent systems.The apparatus is also useful for the separation of highly polar compounds such as sugars,hippuric acid, and related compounds, which require the use of polar two-phase solvent systems. 

The interfacial tension between the various polymer phases in the composite latex particles is of paramount importance in determining their final morphology. Other factors, such as the mode of monomer addition, the surface polarity of the polymer particles, initiator type, surfactant type, the presence or absence of crosslinking of one or more of the polymer phases, and the presence of chain transfer agents will also strongly influence the final particle structure. In addition, a survey of methods used to characterize the composite latex particles has been given. 

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