Rubber nanocomposites based on compatibilized NBR/SBR blends using a series of amphiphilic montmorillonites

Abstract

The montmorillonite (MMT), Mont-0, was treated with different levels of appropriate corresponding amounts of cetyltrimethylammonium bromide to yield a variety of biphasic MMTs exhibiting different hydrophilic-lipophilic balance ranging gradually up to the highly hydrophobic form (Mont-100), which was proved using Fourier transform infrared spectra as well as x-ray diffraction, thus the produced forms can be arranged in the following order according to the decrease in hydrophilicity: Mont-0 > Mont-25 > Mont-50 > Mont-75 > Mont-100. In a following step, the obtained MMTs were attempted for use as reinforcing fillers that may exhibit in the mean time a compatibilizing effect, for acrylonitrile-butadiene rubber (NBR)/styrene-butadiene rubber (SBR) (50/50) rubber blend, which is known to be physically incompatible. The mechanical performance of the blends comprising different loadings of MMT forms demonstrated advancement in most of the cases accompanied by acceleration in rheometric characteristics indicating enhancement by different extents in compatibility between the phases. The results were explained on the light of the potential of these MMT forms to bind both phases of the blend through hydrophobic-hydrophobic interactions with the nonpolar part (SBR) and polar-polar interactions with the polar part (NBR) of the blend, which diminishes the molecular mobility of the macromolecular chains thus preventing progress in phase separation. These findings were additionally proved using scanning electron microscopy and XRD that confirmed a dependent contribution of both phases in interfacial interactions with the biphasic fillers as a function of the hydrophobization level.

Novel interpenetrating amphiphilic Co‐networks based on compatibilized NBR/SBR‐montmorillonite composites: A study on the oil absorption characteristics

“…The basal spacing (d001) of the virgin montmorillonite was originally about 1.42 nm as calculated from the corresponding diffraction peak at 6.22°, expanded proportionally with the amount of modifier to 1.52 nm (5.82°) for Mont‐50, 1.77 nm (4.99°) for Mont‐75 and finally reached around 1.88 nm (4.71°) at complete cation exchange, which is in coherence with the proposed scheme . These montmorillonite forms were applied as compatibilizing agents beside their main filling role and proved to be efficient.…”

“…As a result the overall properties of the resulting blend can be enhanced. Recently, we reported the possibility of using a wide range of organic‐inorganic hybrid structures based on montmorillonite, treated with a cationic surfactant to different levels, according to its original cation exchange capacity (CEC) so that it can acquire amphiphilic character, as compatibilizing agents (Scheme ) .…”

“…Na‐Montmorillonite was dispersed in a suitable amount of distilled water containing a proportional calculated amount of a cationic surfactant (CTAB) based on the originally determined cation exchange capacity (CEC) of the montmorillonite, 68.7 meq/100 g . Generally, the treatment is accomplished via cation exchange between the cationic surfactant and montmorillonite's exchangeable sodium content.…”

“…Thus, these advantageous features of rubber materials have encouraged us recently to develop novel amphiphilic interpenetrating co‐network structures based on acrylonitrile−butadiene rubber (NBR) and SBR following the conventional system of vulcanization while the introduction of wide range of montmorillonites, according to their hydrophilic/hydrophobic character beside their filling function, was to ensure effective networks interpenetration. This would broaden the applicability of these materials as sorbents for oils with a wide range of polarity.…”

Influence of the hybrid materials based on carbon nanotubes and tannic acid on the rheological, thermal and mechanical performances of nitrile butadiene rubber composites

“…Unfortunately, the reinforcing effect of CNT has been limited due to the difficulties associated with homogeneous dispersion in the matrix and the lack of interfacial interaction between CNTs and polymer matrix . In general, using organic‐modifiers or silane coupling agents to modification the inorganic filler is the most common method to improve mechanical properties of rubber composites . However, the reinforcing effect is less effective and the coupling agents are not environment‐friendly.…”