Selective Orientation of Needlelike Sepiolite Nanoclay in Polymer Blend for Controlled Properties

[Image: see text] Sepiolite nanoclay needles have been selectively localized either in the natural rubber (NR) phase or in the carboxylated nitrile rubber (XNBR) phase of the XNBR/NR (50/50) blend prepared by the solution casting method. In a systematic manner, the role of the difference value between the interaction parameter of individual blend components (NR or XNBR)/solvent and the interaction parameter of sepiolite nanoclay/solvent in selectively localizing the sepiolite nanoclay to the NR phase or the XNBR phase of the XNBR/NR (50/50) blend has been explored. A higher percentage of sepiolite nanoclay resides in the dispersed NR phase when the difference value between the interaction parameter of NR/solvent and the interaction parameter of sepiolite nanoclay/solvent is lower than the difference value between the interaction parameter of XNBR/solvent and the interaction parameter of sepiolite nanoclay/solvent. On the other hand, a higher percentage of sepiolite nanoclay resides in the continuous XNBR phase when the difference value between the interaction parameter of XNBR/solvent and the interaction parameter of sepiolite nanoclay/solvent is lower than the difference value between the interaction parameter of NR/solvent and the interaction parameter of sepiolite nanoclay/solvent. It has been shown that by judiciously choosing different solvent combinations to prepare the blend and to disperse nanoclay, it is possible to fine-tune the difference value between the interaction parameter of individual blend components (NR or XNBR)/solvent and the interaction parameter of sepiolite nanoclay/solvent and dictate the selective localization of sepiolite nanoclay to the NR phase or the XNBR phase of XNBR/NR (50/50) blend. This study shows that it is possible to generate a rubber blend with controlled properties by selectively localizing needlelike sepiolite nanoclay in the dispersed phase or the continuous phase of the rubber blend prepared by the solution casting method.