Control of organoclay structure in hydrocarbon polymers

Abstract

Two different kinds of organoclays were prepared by mixing a pristine montmorillonite and a double‐chain ammonium salt in many different thermoplastic or elastomeric polymers. Independently of the chemical nature of the considered polymers, the obtained organoclays presented a basal spacing of 4 or 6 nm, when the mixing occurred in the absence or in the presence of a small amount of stearic acid (SA), respectively. X‐ray diffraction and Fourier transform infrared measurements support the hypothesis that these two kinds of organoclays correspond to paraffin‐type tilted and perpendicular bi‐layer intercalates, respectively. The co‐intercalation of SA molecules with the double‐chain amphiphile is suggested, to explain the observed expansion of the clay interlayer distance. The obtained results suggest an easy way to control the organoclay structure in polymer composites. Moreover, the authors on the basis of these results propose a criticism to the extensive literature that systematically explains most d basal spacing increase observed for clays in polymer with the penetration of apolar polymer chains in the clay interlayer space. Copyright © 2010 John Wiley & Sons, Ltd.

Recent Advancements in Rubber Nanocomposites

“…As already reported, 4,5 the introduction of the ammonium cation in the interlayer space leads to the expansion of the d 001 basal spacing and, in the case of 2HT as the ammonium cation, to a high degree of order, as revealed by the presence of some (00') reflections. 32,33 Figure 4 shows the XRD patterns of the carbon fillers formed by layers of sp 2 -bonded carbon atoms: CB (Figure 4a), CNT ( Figure 4b), and nanoG ( Figure 4c), to confirm what was reported above on the presence of the identical crystalline repeating unit in the three carbon allotropes, which are, however, endowed with different degrees of order.…”

The Role of CNTs in Promoting Hybrid Filler Networking and Synergism with Carbon Black in the Mechanical Behavior of Filled Polyisoprene

“…However, the dispersion of CNTs (and clays) in a polymer matrix as individual particles is still a main issue and is the subject of major research efforts,5–7 as CNTs are not available as individual tubes but as tangled webs. Some of the authors have been actively investigating aspects such as interaction, dispersion, and structure of nanofillers in polymer matrices, focusing the attention on the preparation of tailor‐made nanostructures based on either layered silicates23, 24 or CNTs 25…”

Rubber‐Clay Nanocomposites

“…A strong reduction of the dynamic modulus was observed also by increasing the temperature [50]. The 2-D melting of the paraffinic chains substituents of the compensating ion [105] was commented as a possible explanation [66,101].…”

“…The preparation of the organoclay in situ in the rubber matrix was reported by Galimberti [57,[64][65][66][67], by adopting the melt blending approach, with all the processing technologies mentioned in paragraph 5.2. An even clay dispersion was achieved in the rubber matrix and the organoclays revealed a lower number of stacked layers.…”