Filler Networking of a Nanographite With a High Shape Anisotropy and Synergism With Carbon Black in Poly(1,4-Cis-Isoprene)–based Nanocomposites

Abstract

A nanoGraphite (nanoG) having a high surface area and a high shape anisotropy, defined as the ratio between the crystallite dimensions in a direction orthogonal and parallel to structural layers, was used to prepare nanocomposites based on poly(1,4-cis-isoprene) (IR), in the neat polymer matrix and in the presence of carbon black (CB). Tensile and dynamic-mechanical measurements showed that nanoG forms a filler network at a relatively low concentration in neat IR and a hybrid filler network at a lower nanoG concentration in the presence of CB. A synergistic effect between the two carbon allotropes was found: composites containing both fillers present initial modulus values much higher than those calculated through the simple addition of the initial moduli of the composites containing only CB or nanoG.

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

“…The number of stacked layers appears to increase also for CNT, from the pristine allotrope to the crosslinked composite. As already commented in previous publications [25,26], a remarkable pressure is applied on the rubber sheet, during the crosslinking step. As a consequence, the rubber composite moves towards a minimum of energy and the graphitic aggregates achieve a higher degree of order.…”

“…All the composites were finally homogeneized by passing them 5 times on a two roll mill operating at room temperature. Such mixing procedure has been already adopted in previous works [24][25][26] and allowed to obtain even distribution and dispersion of the carbon fillers, both nano-and nano-structured, as revealed by transmission electron microscopy. In particular, composites based on synthetic poly(isoprene) were prepared with amount 30 phr of the same CB and CNT used in the present work and with 33.3 phr of HSAG.…”

“…Musto, V. Barbera, V. Cipolletti, A. Citterio, M. Galimberti reinforcement of nanosized carbon allotropes and CB has been clearly shown [25,26] and correlation has been established between the filler-polymer interfacial area and the initial modulus of composites with CNT, CB and with the hybrid filler system: a master curve was obtained, able to fit all the experimental points [25,26]. It is well known that elastomeric composites, in order to find large scale application, have to be not only reinforced but also crosslinked.…”

“…The intensities of reflections were not corrected for polarization and Lorentz factors, to allow a better visibility of (00ℓ) peaks. d-spacings were calculated using Bragg's law [26]. The D hkℓ correlation length of CNT and HSAG crystals was determined applying the Scherrer equation (Equation (1) [29]): (1) where: K is the Scherrer constant, λ is the wavelength of the irradiating beam (1.5419 Å, CuKα), β hkℓ is the width at half height, and θ hkℓ is the diffraction angle.…”

“…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]. In particular, in poly(1,4-cis-isoprene) as the polymer matrix, the synergistic effect on the mechanical…”