Effect of the Phase Modifier Concentration on the Mechanical Properties
Inclusion of the rubber phase modifier has prominent effect in bringing up the [T.sub.g] for the elastomer phase modified TPEs, (from -54.7[degrees]C for A to -52.6[degrees]C for [E.sub.8] and to -41.2[degrees]C for [B.sub.8]) as revealed in tan [delta] versus temperature plot (Fig.
Incorporation of SEBS into EPDM-iPP as phase modifier shows an interesting observation in AFM surface morphology for EPDM-iPP-SEBS ternary blends.
Another phase modifier, SEBS, being a block copolymer, follow order-disorder transition (ODT) at the temperature (190[degrees]C) and high shear (40 rpm with sigma rotors) of blending.
Therefore, silica surface must simultaneously contain both groups, being their relative amount dependent on the amount of the cationic groups which came from the phase modifier (e.g., ammonium hydroxide or salts), which are interacting with the silanol groups, decreasing the retention trend of the stationary phase toward the metabolites that are being separated by the TLC technique .
Besides, to make a pseudo-reverse phase that allows compounds with a high polarity to be resolved more adequately, a small amount of phase modifier (N[H.sub.4]OH) was added to the last three systems (MP-4a, b, and c), which promoted a considerable improvement in the chromatographic separation behavior (Figure 1).
The proposed experimental system allowed a suitable separation and localization of such type of components, whose dispersion on the plate was favored by the use of N[H.sub.4]OH as a phase modifier. The last system was intentionally designed to be scaled to preparative TLC plates, which is a preliminary stage to the identification of components; at this time, we are working on that stage.
Some amines have been used as phase modifiers, since they are able to mask silanol groups, reduce the silanophilic interactions with analytes, and, therefore, increase their retention factors ([R.sub.F]) [20,26,27].