Silica interactions, polymer

The phenyl modified polymers possess the optimum combination of high temperature and elastomeric properties and were used in the study of formulation parameters These variables can have an important effect on the thermal stability and property profile of vulcanized systems For example, the use of reinforcing silicas, peroxide content, and oxidative stabilizers have been shown to be important ( 3, 10, in However, polymer-silica interactions had the most pronounced effect on retaining properties during high temperature aging studies ... 

The sol-gel technique to generate nanosilica particles within a polymer matrix has been a useful process which gives specific interphase impact between the organic matrix and inorganic component. The incorporation of the filler particles into polymers using this process avoids the aggregation of the nanofiller within the polymer matrix [17]. The polymer-silica interaction depends on the size and shape of the nanofiller particles, their volume fraction, and the interparticle interaction [18]. What s more, these parameters also strongly influence the properties of the nanocomposites. 

The effect of polymer-filler interaction on solvent swelling and dynamic mechanical properties of the sol-gel-derived acrylic rubber (ACM)/silica, epoxi-dized natural rubber (ENR)/silica, and polyvinyl alcohol (PVA)/silica hybrid nanocomposites was described by Bandyopadhyay et al. [27]. Theoretical delineation of the reinforcing mechanism of polymer-layered silicate nanocomposites has been attempted by some authors while studying the micromechanics of the intercalated or exfoliated PNCs [28-31]. Wu et al. [32] verified the modulus reinforcement of rubber/clay nanocomposites using composite theories based on Guth, Halpin-Tsai, and the modified Halpin-Tsai equations. On introduction of a modulus reduction factor (MRF) for the platelet-like fillers, the predicted moduli were found to be closer to the experimental measurements. 

For sub-micron silica particles with grafted PDMS (up to 22 K), a different result was obtained (Yates and Johnston, 1999). The particles were unstable and flocculated well above the UCSD of the PDMS-C02 binary system. These results may suggest that it is necessary to raise the density to the UCSD for PDMS at infinite molecular weight (theta density). Another possibility is that the parameters used in the theory and simulation are not applicable to PDMS, since the polymer-polymer interactions are far stronger than the polymer-C02 interaction, unlike the case for PFOA. 

Direct experimental data providing the temperature dependence of are not available in the literature. However, as discussed earlier, the dependence of 0 on the quality of the solvent (change in the values of the polymer-solvent interaction parameter) is expected to suggest the trend with temperature also. The experimental determination of

silica particles having polystyrene as the free polymer, indicated [5] that the amount of polymer required to produce phase separation decreased by a factor of three when the theta solvent cyclohexane (x = 0.5) is replaced by the good solvent toluene (x < 0.5). This implies that increased temperatures (reduced values for x) should lead to lower values of the amounts of polymer required for phase separation. It can be safely concluded that the available experimental and theoretical information thus far, exhibits the trend of smaller values of the limiting polymer concentration at higher temperatures. 

This study is devoted to the investigation of porous methacrylate polymeric systems filled with chemically modified fumed silicas. IR and 13C NMR spectroscopies combined with AFM was applied to characterize changes in the material structure, and also the effect of surface functional groups of inorganic particles on the polymer-filler interaction. 

For structuring, the IL has to be immobilised. This can be done using i.e. zeolitic structures or molecular sieves. It is obvious that with increasing surface area of the solid phase, the motion of the liquid and the proton transport will be hindered. From polymerisation experiments it is known that the stiffening of polymers by cross-linking can be compared with the polymer-surface interaction. Electrode surfaces and solids such as silica, carbon black or cathode powder also stiffen the polymer [52]. This can be explained by different transport properties at the interfaces. As a consequence it must be expected that at the surface of the added particles the ionic liquid will behave in a different way than in the immobilised liquid phase. 

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