Chemically Reduced Graphite Oxide with Improved Shape Anisotropy

Abstract

Chem. reduced graphite oxide with strongly improved shape anisotropy was prepd. by Staudenmaier oxidn. of high surface area graphite, followed by hydrazine monohydrate redn. Selection of the starting graphite was effected on the basis of the highest shape anisotropy of the crystallites. The overall oxidn.-​redn. procedure preserves the in-​plane order of graphite and dramatically increases the out-​of-​plane disorder, which becomes similar to that one of carbon black. In particular, the overall procedure led to aggregates of few piled structural layers (D⊥ ≈ 2 nm) with increased periodicity perpendicular to the layers (from 0.339 nm up to 0.362 nm) and with high shape (D‖/D⊥ ≈ 13) and strain (ε⊥/ε‖ ≈ 15) anisotropy

Interactive effects between carbon allotrope fillers on the mechanical reinforcement of polyisoprene based nanocomposites

“…By applying the Scherrer equation (see Equation (1)) to the 002 reflection at 26.5° as 2# value in the pattern of CB-15-nanoG, the number of layers stacked in a crys- curve averaging the three fitting curves of the systems in a) is shown as well talline domain was calculated to be about 72. Interestingly, this number is higher than the one detected in the pristine nanoG sample [21]. It could be commented that the high pressure applied in the crosslinking step brings nanoG to a minimum of energy, that means to a higher crystallinity.…”

“…In ref. [20], CB was used in combination with a nano-graphite with a high shape anisotropy [21] (hereinafter nanoG), defined as the ratio between the crystallites dimensions in directions orthogonal and parallel to structural layers. Hybrid nanoG-CB networks were observed in TEM micrographs from a nanoG level of about 8 php and synergistic effects between nanoG and CB were observed on the initial moduli values of the nanocomposites containing the hybrid filler network.…”

Master curves for the sulphur assisted crosslinking reaction of natural rubber in the presence of nano- and nano-structured sp2 carbon allotropes

“…Correlation between surface area and oil absorption appears for CNT, CB N110 and for the CB grade with lower surface area, CB N326, whereas the oil absorption for HSAG appears relatively low. The number of graphene layers stacked in crystalline domains was calculated by applying the Scherrer equation (see experimental section) to the (002) reflection in the XRD pattern, as already reported [23]. For HSAG, such number is about 35 in its pristine state and increases to about 70 in the crosslinked composite.…”

“…Carbon black and carbon nanofillers have been separately investigated for quite a long time. Recently, features such as crystallinity, shape anisotropy, density, surface area and oil absorption of CNT, a nanosized graphite and CB have been comparatively investigated [23,24]. Moreover, studies on synergistic effects have been performed, both in thermoplastic [15] and elastomeric matrices [24][25][26][27].…”

sp2 carbon allotropes in elastomer matrix: From master curves for the mechanical reinforcement to lightweight materials

“…Indeed, increasing interest is on hybrid systems based on CB-CNT and CB-GRM [24], developed by partially substituting CB with nanometric carbon allotropes. In most studies, CB and carbon nanofillers have been separately investigated and only recently [25,26] crystallinity, shape anisotropy, density, surface area and oil absorption of CNT, a nanosized graphite and CB have been compared. Interestingly, synergistic effects on mechanical reinforcement, between CB and nanofillers, have been shown in both elastomeric [17,24,25,[27][28][29][30] and thermoplastic [31] matrices.…”