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Functional elastomer nanocomposites have found numerous applications in diverse hi-tech areas. Transport phenomena, such as electrical conductivity, thermal conductivity and gas/liquid barrier properties, have been the major focus of functional elastomer nanocomposite research. Despite essential progress in these areas, a summary and discussion of state-of-the-art strategies for regulating the transport performances of nanocomposites based on the transportation mechanisms of electrons, phonons and mass are lacking. In the present review, a brief introduction of transport mechanisms in elastomer nanocomposites precedes a systematic summary of the important progress in elastomer nanocomposites with electrical/thermal conductivities and lowered mass permeabilities, with emphasis on the latest structural control strategies for tuning transport properties. Key applications of functional elastomer nanocomposites related to transport phenomena are also introduced. Overall, this review summarizes the state of the art in the design and performance enhancement of elastomer nanocomposites based on the relationships between their structures and transport properties, governed by the components/composition, interface/dispersion and fabrication. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride)(PVC)/halloysite nanotubes (HNTs) nanocomposites were prepared by melt blending. The effects of HNT content on the mechanical properties, morphology, and rheological properties of the nanocomposites were investigated. The results showed that HNTs were effective in toughening and reinforcing PVC nanocomposites. The notched impact, tensile and flexural strength, and flexural modulus of the nanocomposites were remarkably increased compared with those for the pure PVC. Scanning electron microscopy (SEM) results illustrated the ductile behavior of the nanocomposites, with a possible cavitation mechanism. Transmission electron microscopy (TEM) results showed that HNTs were uniformly dispersed in the PVC matrix. Interfacial interaction of hydrogen bonding between the HNTs and PVC matrix was substantiated. The plasticization times of PVC/HNTs nanocomposites were found to be shorter and the equilibrium torque was higher than that for the pure PVC. [ABSTRACT FROM PUBLISHER]

Graphical abstract Highlights • A novel hydrothermal self-assembled strategy is proposed for constructing 3D segregated graphene network in polymer matrix. • The shape of the products can be controlled by changing the types of reactors. • The nanocomposites present unique mechanical properties and competitive electrical conductivity. • The post-impregnation process can significantly improve the electrical conductivity of the nanocomposites. Abstract Constructing three-dimensional segregated graphene (3DG) network in polymer matrix is very effective in fabricating highly conductive polymer composites. However, it remains challenging to control the distribution of graphene with a concise and efficient method though the past efforts have been made. In this contribution, we propose a novel hydrothermal self-assembled strategy in combination of the post-impregnation process to prepare highly conductive polymer/graphene composites. Specifically, styrene-butadiene rubber/graphene nanocomposites with a three-dimensional graphene network (3DG-SBR) were prepared by employing the hydrothermal self-assembling, followed by impregnating by silver nitrate. The resultant graphene/styrene-butadiene rubber/silver particle (3DG-SBR-Ag) nanocomposite with 1.66 vol% of graphene exhibits the conductivity of 512 S m−1, which is competitive to those prepared by template-guided assembly strategy. Impressively, the polymer composite possesses mechanical robustness due to the strong interfacial reaction between graphene and polymer matrix. This synthetic approach for graphene-based nanocomposites is generic, scalable, flexibility in complex geometry and cost-effective. The as-prepared products could potentially be applied as competitive candidates for practical application in electromagnetic wave absorption and electromagnetic interference shielding. [ABSTRACT FROM AUTHOR]

It remains a huge challenge to realize the homogeneous graphene dispersion in elastomer matrix by a simple and general compounding method. Herein, we develop a straightforward slurry compounding method for preparation of rubber/graphene composites with well-dispersed graphene. Specifically, TPG (tea polyphenol reduced graphene)/ethanol slurry was first collected by solvent exchange after the reduction of graphene oxide by tea polyphenol and then directly melt compounded with chlorosulfonated polyethylene (CSM) in a two-roll mill to produce the composites. As revealed by the XRD and morphological studies, TPG homogeneously dispersed in CSM matrix, which together with the strong interfacial interaction between TPG and CSM contribute to the remarkable improvement in mechanical properties of the resulted composites. We envision that the present work offers a straightforward yet effective methodology for preparing high-performance elastomer/graphene composites via conventional melt compounding. [ABSTRACT FROM AUTHOR]

The energy loss of tires during service is closely related to the hysteresis of tire tread, which is governed by the dispersion and interface of the elastomer nanocomposites. However, traditional undeformable spherical fillers have approached a bottleneck in regulating the viscoelasticity and lowering the hysteresis loss. Herein, the designed covalent interface in the graphene/elastomer nanocomposite maximizes the reinforcement of the nanomaterial as well as minimizes the dynamic energy loss. The reinforced interfacial interaction, an ultralow percolation threshold of tensile strength and high reinforcement synergistically benefit these nano-organized rubber nanocomposites. The energy losses under dynamic loading are largely suppressed in this material, due to the reduced nano-scale frictions. The developed graphene/elastomer nanocomposites are applied to typical dynamic rubber product - auto tires, and the tests indicate that these tires possess energy efficiency close to the highest “A-grade”, which gave great economic and environmental improvements. The critical role of interface structure in the performance of the elastomer nanocomposites was revealed and new design strategy for low dynamic energy losses in rubber products was suggested. [ABSTRACT FROM AUTHOR]

Layered inorganics are promising in the fabrication of elastomeric nanocomposites with enhanced barrier property. Recently, boehmite (BM) nanoplatelets have emerged as alternative layered inorganics to clays and double hydroxylates as the functional reinforcement for rubbers. In the present paper, natural tannic acid (TA) is introduced as a novel interfacial modifier in BM-filled styrene–butadiene rubber (SBR) nanocomposites. The modification mechanism and interfacial interactions in the nanocomposites are fully characterized. Due to the strengthened interface and the comparatively finer dispersion state of BM in the nanocomposites, significantly enhanced mechanical properties are found in the modified system. At higher BM loadings (higher than 40 phr), the modified system possesses a much lower gas permeability compared with the unmodified counterpart. Very interestingly, the TA-modified SBR/BM nanocomposites exhibit high tensile strength yet impressively low moduli compared with previously reported rubber nanocomposites filled with other nanofillers. [ABSTRACT FROM AUTHOR]

Vulcanization accelerant N-cyclohexyl-2-benzothiazole sulfenamide (CZ) was used as a surface modifier and chemically grafted on the surface of halloysite nanotubes (HNTs) to obtain CZ-functionalized HNTs (HNTs-s-CZ). It was found that HNTs-s-CZ could be homogeneously dispersed into styrene-butadiene rubber (SBR). The grafted CZ molecules, exactly located at the filler-rubber interface, reduced the activation energy of vulcanization of SBR/HNTs-s-CZ compounds. Besides, the density of chain segments introduced by the interfacial phase of SBR/HNTs-s-CZ nanocomposites was higher than the other nanocomposites with silane-modified HNTs (m-HNTs) or pristine HNTs, manifesting an indication of enhanced filler-rubber interfacial interaction in SBR/HNTs-s-CZ nanocomposites. Consequently, SBR/HNTs-s-CZ nanocomposites showed excellent mechanical properties. The tensile strength could be enhanced by as much as 38.6% and 102.5% compared to those of SBR/m-HNTs and SBR/HNTs nanocomposites, respectively, though containing equivalent accelerant component. The value of this work lies in the fact that apparent properties improvement of elastomer composites has been achieved by the incorporation of vulcanization accelerant-functionalized HNTs, which may be fruitful for the rational design of filler surface treatment and offer new scientific and technological opportunities for the preparation of high performance elastomer composites. [ABSTRACT FROM AUTHOR]

Abstract: Graphene oxide/carboxylated acrylonitrile butadiene rubber (GO/XNBR) nanocomposites with high mechanical and gas barrier properties were fabricated by using a simple and environment-friendly latex co-coagulation method. The oxygen-containing groups attached to the surface of GO generate strong interactions with the XNBR chains through hydrogen bonding (H-bonding), as confirmed by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) results. The morphology of the nanocomposites was characterized by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD), which show highly exfoliated and uniform dispersion of GO sheets in the matrix. The tensile strength and tear strength of the nanocomposite with 1.9vol% of GO increased by 357% and 117%, respectively, over those of the matrix. The gas permeability of the nanocomposite is significantly lower than that of the matrix. The high mechanical properties and low gas permeability of the nanocomposite are correlated to the homogeneous dispersion of the GO sheets and strong interfacial interactions, which facilitate the load transfer from XNBR to the GO sheets. [Copyright &y& Elsevier]

Abstract: Methacrylic acid (MAA) is investigated as a novel in situ interfacial modifier for styrene-butadiene rubber (SBR)/boehmite (BM) composite via a direct blending method. The reaction mechanism for the modification was revealed to be the BM/MAA coordination and MAA/rubber grafting reaction. The substantiated BM/MAA coordination can improve the dispersion of BM in rubber matrix. It is illustrated that the ultimate mechanical performance and interfacial interaction are significantly enhanced by the in situ modification. The strong interaction between BM and SBR and the improved dispersion of BM in the rubber matrix are responsible for the largely enhanced mechanical properties. [Copyright &y& Elsevier]

Abstract: In this contribution, halloysite nanotubes (HNTs), a kind of natural hydrophilic nanoclay, are incorporated into polypropylene (PP) for tailoring the surface microstructures of the composites prepared by solution casting. HNTs act as heterogeneous nuclei for PP, which leads to the change of phase separation process during drying of the composites and consequently the microstructures of composite surfaces. Micro-papilla like hybrid spherulites with nanostructures are formed on the PP/HNTs composite surfaces. The rough surfaces demonstrate superhydrophobicity with a maximum water contact angle as nearly 170° and sliding angle of about 2°. The spherulites size, surface roughness, and wetting property of PP can be tuned by HNTs. HNTs can significantly improve the thermal degradation behavior of the composites which is attributed to the well-dispersed HNTs and the improved interfacial interactions by the nucleation effect. The present work provides an alternative routine for preparing polymer superhydrophobic surfaces via tailoring the surface microstructures by adding nanoparticles in a solution process. [ABSTRACT FROM AUTHOR]