Carbon Nanotubes Networking in Styrene‐Butadiene Rubber: A Dynamic Mechanical and Dielectric Spectroscopy Study

Abstract

The study of the reinforcement network in elastomer compounds is one of the most relevant issues for the application of these materials because their properties are strongly dependent on the obtained morphology. To this regard, the viscoelastic and dielectric behavior of vulcanized styrene butadiene rubber (SBR) reinforced with different amounts of carbon nanotubes (CNT) have been investigated and compared with the vulcanized unfilled SBR and the vulcanized SBR samples reinforced with a conventional amount of carbon black (40 phr). Differential scanning calorimetry (DSC) measurements have been carried out to highlight possible differences of the glass transition temperatures for all the reinforced compounds. The percolation threshold value of the nanocomposite samples has been estimated by dielectric analysis. Finally, dynamic mechanical analysis (DMA) measurements have been performed in tensile mode in the temperature range of −60 to 80 °C to obtain both E′ and E′′. From these experimental data, the master curve for each sample has been estimated by using the time–temperature superposition principle in combination with the vertical shift approach. From the analysis of this latter, the activation energy, associated to the thermal movement of the reinforcement network, has been calculated to better elucidate the reinforcement mechanism in the nanocomposites.

The Time–Temperature Superposition of Polymeric Rubber Gels Treated by Means of the Mode-Coupling Theory

“…The material studied here consists of a "doped" styrene-butadiene rubber (SBR rubber) [25]. In particular, it is considered a rubber filled with carbon nanotubes (CNT) at different concentrations with 40 phr carbon black (CB).…”

“…The relative CNT concentration (C) is reported as phr-parts per hundred rubber (phrCNT). Their viscoelasticity was measured through a series of DMA experiments evaluating the complex modulus E via a series of tensile strength tests in the following parts: the shear E ′′ , the loss E ′ , and the relative loss angle δ (see [25] for details).…”

“…Therefore, only by taking these specific peculiarities into account can an appropriate description of this material be possible. The data we analyze here have been previously published in cooperation with the National Institute of Industries and Technology (INTI, Argentina) [25]. The reader is referred to [25] for full experimental details.…”

“…The data we analyze here have been previously published in cooperation with the National Institute of Industries and Technology (INTI, Argentina) [25]. The reader is referred to [25] for full experimental details. Furthermore, it should be noted that CNTs have a remarkable influence on the physical/chemistry properties of polymeric materials, including viscoelasticity and thermal characteristics.…”

The Time Temperature Superposition in Polymeric Rubber Gels Treated by Means of the Mode-Coupling Theory

“…Starting from these considerations, we have considered to give, in the present work, a new contribution to the TTS investigation by considering the dynamic mechanical analysis (DMA) to characterize the viscoelastic behavior of cross-linked Styrene-Butadiene rubbers (SBR) filled with Carbon Nanotubes (CNT) at different concentration, in the gel phase, and with 40 phr Carbon Black (CB). The data we analyze here have been previously published by some of the authors in cooperation with the National Institute of Industries and Technology (INTI, Argentina) [23]. The reader is referred to [23] for full experimental details.…”