Natural Rubber Nanocomposites Research Articles

Conductive epoxidized natural rubber nanocomposite with mechanical and electrical performance boosted by hybrid network structures

Stretchable conductive elastomers have aroused great interest in recent years as candidates for smart rubber materials. A single conductive filler embedded in an elastomer matrix has been demonstrated to provide electrically conductive pathways, but the filler network can be improved by adding a second conductive filler. Herein, reinforced conductive epoxidized natural rubber (ENR) composites were designed to have hybrid nanostructures of multiwalled carbon nanotubes (MWCNT) with few-layer graphene (FLG) nanofillers. With both MWCNT and FLG, the ENR nanocomposites exhibited improved mechanical performance, filler dispersion, and electrical properties. The tensile strength of ENR filled with MWCNT and FLG was remarkably improved, and the Halpin-Tsai model revealed effective reinforcement by the MWCNT/FLG hybrid filler. Meanwhile, the electrical percolation threshold was decreased by 70% from 1.19 vol% for single nanofiller to 0.36 vol% for hybrid nanofiller. The main reasons for remarkable boosting of desirable characteristics of the hybrid nanocomposites are the uniform filler dispersion and the bridging between MWCNT and FLG through π-π interactions and filler-rubber interactions. Thus, ENR reinforced with hybrid nanostructures is a highly promising advanced conductive elastomeric material for smart rubber applications.

A Review of Natural Rubber Nanocomposites Based on Carbon Nanotubes

A Review of Natural Rubber Nanocomposites Based on Carbon Nanotubes

Green Nanocomposites of Natural Rubber/ Olivine Nanosilica: Viscoelastic, Mechanical, Transport and Thermal Characterizations

Green Nanocomposites of Natural Rubber/ Olivine Nanosilica: Viscoelastic, Mechanical, Transport and Thermal Characterizations

A Review of Natural Rubber Nanocomposites Based on Carbon Nanotubes

A Review of Natural Rubber Nanocomposites Based on Carbon Nanotubes

Green and sustainable biosynthesis of iron oxide nanoparticle (ION) from pomegranate seed and the development of highly reinforced ION based natural rubber (NR) nanocomposite in presence of epoxidized natural rubber (ENR) as compatibilizer

This research article explores a green and sustainable approach for the biosynthesis of iron oxide nanoparticles (ION) from a natural source of non-edible waste part, seed of pomegranate fruit and the studies its application in natural rubber (NR) as reinforcing filler along with a compatibilizer, ENR. The formation of naturally deep brown colored ION was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM) analysis and Energy dispersive X-ray (EDX) microanalysis. The experimental studies shows that the combination of only 1 part per hundred parts of rubber (phr) of the ION and 3phr of ENR can outstandingly increase the overall tensile strength (TS) by nearly 41% and improve others cure and mechanical properties of the NR composite. The cure properties like the maximum rheometric torque (R∞) and the cure rate index (CRI) are increased and the vulcanization time is saved by nearly 24%. The mechanical properties like the modulus at 100%, 300% elongation and the EB (%) are improved in presence of 1phr ION and 3phr of ENR. The thermal aging resistance and thermal stability of the NR composites are also improved in presence of both the ION and the ENR. The compatibility among the ION, ENR and NR was confirmed by analyzing the thermodynamic parameters ΔG and ΔS. The morphology of the nanocomposite was studied by FESEM analysis which confirms the uniform distribution of ION throughout composite matrix. The improvement in the thermal stability of the NR composite is confirmed by the oxidative thermal aging behavior and thermogravimetric analysis (TGA) & derivative thermogravimetric analysis (DTG).

Use of visible pulsed photoacoustic technique for the non-destructive measurements of absorption coefficients, thermal diffusion and viscosity properties of natural and clay-blended rubber nanocomposites

Use of visible pulsed photoacoustic technique for the non-destructive measurements of absorption coefficients, thermal diffusion and viscosity properties of natural and clay-blended rubber nanocomposites

Optimization of graphene nanoplatelets dispersion and nano-filler loading in bio-based polymer nanocomposites based on tensile and thermogravimetry analysis

The incorporation of graphene nanoplatelets (GNPs) has attracted massive attention in polymer nanocomposite production. In this work, GNPs reinforced nanocomposites of liquid natural rubber (LNR) toughened poly (lactic acid) (PLA)/poly (aniline) (PANi) were fabricated through melt-mixing using internal mixer. The effects of ultrasonic treatment period, mixing rotor speed and GNPs loadings in PLA-LNR/PANi was investigated. A premix ultrasonication of LNR/PANi with GNPs for 1 h was found to be the most effective period as compared to the longer sonication time. The best melt-mixing of the materials was achieved at 100 rpm, in accordance to the tensile properties as well as homogeneous dispersion and distribution of nano-filler as shown in thermogravimetry analysis. Results revealed that the optimum loading was found at 0.4 wt.% of GNPs with excellent enhancement in tensile strength (25 MPa), tensile modulus (1188.9 MPa) and thermal stability of the nanocomposite, as proven by ANOVA statistical analysis.

Cellulose nanocrystal‐mediated assembly of graphene oxide in natural rubber nanocomposites with high electrical conductivity

AbstractThis study reports a green and powerful strategy for preparing cellulose nanocrystal (CNC)/graphene oxide (GO)/natural rubber (NR) nanocomposites hosting a 3D hierarchical conductive network. Due to good dispersibility and amphiphilic nature of CNC, well dispersed CNC/GO nanohybrids were prepared. Hydrogen bonding interactions between CNC and GO greatly enhanced the stability of the CNC/GO nanohybrids. CNC/GO nanohybrids were introduced into NR latex under sonication and the mixture was cast. Self‐assembled CNC/GO nanohybrids preferentially dispersed in the interstice between latex microspheres allowing the construction of a 3D hierarchical conductive network. By combining strong hydrogen bonds and 3D conductive network, both electrical conductivity and mechanical properties (tensile strength and modulus) have been significantly improved. The electrical conductivity of the nanocomposite with 4 wt% GO and 5 wt% CNC exhibited an increase of nine orders of magnitude compared to the nanocomposite with only 4 wt% GO; meanwhile, the electrical percolation threshold was 3‐fold lower than for NR/GO composites.

Payne effect of carbon black filled natural rubber nanocomposites: Influences of extraction, crosslinking, and swelling

Rubber nanocomposites experiencing dynamic shears at large strain amplitudes (γ) exhibit the nonlinear Payne effect featured by decays of storage and loss moduli (G′ and G″) or by G′ decay accompanied with G″ overshoot near a critical strain amplitude. The occurrence of the Payne effect has been assigned to damages of “filler network” and rubber-filler interfacial interactions for a long time and to Rouse dynamics of rubber chains recently. To solve the dispute, influences of extraction, crosslinking, and paraffin swelling on the Payne effect of carbon black filled natural rubber nanocomposites are investigated systematically. Master curves of G′ as a function of γ could be always created, and overshoot of G″ in the filled vulcanizates weakens with increasing filler content and intensifies by dilution via paraffin swelling, suggesting that the Payne effect is not mainly rooted in the “filler network” and rubber-filler interfacial interactions. The filler reduces the onset strain amplitude of the Payne effect by amplifying microscopic strain amplitude of the rubber phase, irrespective of whether the matrix is crosslinked or not and whether the crosslinked matrix is swollen or not. Partial removal of bound rubber by compounding the paraffin swollen compounds could lower modulus and eliminate G″ overshoot of the deswollen vulcanizates without influence on the mechanism of G′ decay accompanying Payne effect. The overshoot is found to be closely related to the overall viscous characteristic of the vulcanizates in the linear viscoelastic regime. Provided herein are new insights for recognizing the important roles of the viscoelastic rubber phase on the Payne effect of the nanocomposites.

Natural rubber nanocomposites: effect of carbon black/multi-walled carbon nanotubes hybrid fillers on the mechanical properties and thermal conductivity

ABSTRACT This work presents the effect of carbon black (CB)/multiwall carbon nanotubes (MWCNT) hybrid filler system on the mechanical properties and thermal conductivity of natural rubber (NR) based nanocomposites. A 30 phr (parts per hundred of rubber) of CB nanocomposite was used as a reference for which various amounts (0.5, 1, 2 and 5 phr) of MWCNT were incorporated as a CB replacement. Scanning electron microscopy (SEM) was used to investigate the state of dispersion of the CB/MWCNT fillers inside the NR matrix, while dynamic mechanical analysis (DMA) was performed to characterize their storage and loss moduli, Payne effect and loss factor (tan δ). The scorch time (t10) and optimum curing time (t90) gradually increased with increasing MWCNT content due to the shape difference between CB and MWCNT, as well as the adsorption of curatives onto the MWCNT. Finally, due to the intrinsic properties of MWCNT and its synergy with CB, substantial improvements in thermal conductivity and mechanical properties were achieved by the substitution of 5 phr CB with MWCNT. For example, a thermal conductivity of 0.602 W/m.K was achieved, which corresponds to a 80% increase compared to the reference sample. Furthermore, a 72% and 54% increase of the modulus at 100% and 300% strain (M100 and M300) was respectively achieved, while the elongation at break decreased by only 20%.

A Compressive Review on Swelling Parameters and Physical Properties of Natural Rubber Nano composites

The research covered most of the recent scientific research related to strengthening the natural rubber and improving its physical properties. The swelling properties played a substantial role in decreasing the efficiency of the elastomer compounds as a result of immersing or contacting these compounds with organic solvents. Using nanoparticles for inorganic fillings is absolutely essential with a view to expanding the industrial applications of natural rubber Nano-composites. The research covered the latest methods that researchers have used to reduce rubber swelling to the lowest levels. The paper discussed the relationship between swelling properties and mechanical, electrical, curing, and morphology properties. The research also discussed the relationship between swelling properties and the concentration of the filter used to harden the rubber matrix, the swelling capacity, and the type of Nano-composite. All results, which discussed by previous studies showed that improving the thermal, electrical and mechanical properties of the Nano-composites of natural rubber leads to a reduction in the swelling problems of the natural rubber compound, and that selecting or modifying the properties of the filler material gives encouraging and strong results towards reducing the rates of swelling.

Influence of Dual Filler Reinforcement on the Curing and Tribo-Mechanical Behaviour of Natural Rubber Nanocomposite for Tire Tread Application

Influence of Dual Filler Reinforcement on the Curing and Tribo-Mechanical Behaviour of Natural Rubber Nanocomposite for Tire Tread Application

Effect of SiO2 Particles on the Relaxation Dynamics of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy.

The rheological behavior of an epoxidized natural rubber (ENR) nanocomposite containing 10 wt.% of silica particles was examined by time-resolved mechanical spectroscopy (TRMS), exploiting the unique capability of this technique for monitoring the time-dependent characteristics of unstable polymer melts. The resulting storage modulus curve has revealed a progressive evolution of the elastic component of the composite, associated with slower relaxations of the ENR macromolecular chains. Two major events were identified and quantified: one is associated with the absorption of the epoxidized rubber macromolecules onto the silica surface, which imposes further restrictions on the motions of the chains within the polymer phase; the second is related to gelation and the subsequent changes in rheological behavior resulting from the simultaneous occurrence cross-linking and chain scission reactions within the ENR matrix. These were quantified using two parameters related to changes in the storage and loss modulus components.

Influences of carbon nanotubes and graphite hybrid filler on properties of natural rubber nanocomposites

Natural rubber (NR) vulcanizates reinforced by carbon nanotubes (CNT, 3 phr), graphite particles (GP) and CNT/GP hybrid filler (varied GP 0–50 phr) were prepared. The stress relaxation behaviors of various filled samples were characterized by the novel temperature scanning stress relaxation (TSSR) technique to elucidate the state and degree of filler dispersion based on initial relaxation modulus, bound rubber, and thermal stability. The incorporation of CNT/GP hybrid filler in NR matrix improved relaxation modulus, bound rubber, and thermal stability of the nanocomposites. The CNT particles in the hybrid composites prevented the re-agglomeration of dispersed GP after mixing by a thermodynamic effect. It was found that a combination of 3 phr CNT and 30 ph GP gave superior properties to NR vulcanizates. That is, good dispersion and distribution of CNT and GP in the NR matrix provided further significant improvements in electrical conductivity and dielectric constant of the nanocomposites. The NR nanocomposites with high conductivity and low dielectric constant seems to be a semi-conductive substrate to be used in many electrical devices.

Dimensional and Thermal Reliability of Multi-Walled Carbon Nanotube Filled Natural Rubber Nanocomposites

The exceptional mechanical and thermal properties, conceivable with carbon nanotubes (CNTs) make a distinction of them as excellent choices for natural rubber nanocomposite reinforcement. Nigeria, in recent years, has been awash with foreign prostheses, many of which fail to meet the criteria of the International Society of Prosthetics and Orthotics (ISPO) for developing countries. However, there are major marked gaps that make them susceptibility to premature failure and dimensional instability, caused by a high rate of water absorption in a humid environment; owing to the dynamic nature of human gait. This paper critically examines the effect of water absorption, thermogravimetric and dynamic mechanical properties, on carbon nanotube-reinforced natural rubber nanocomposite (NC) for prosthetic foot application. CNTs were synthesised via catalytic chemical vapour deposition (CCVD) technique and the NCs were produced by using an electrically heated hydraulic press. Thermogravimetric analysis (TGA), water absorption rate and dynamic mechanical analysis (DMA) of the nanocomposites were carried out with a view to comparing the various compositions used in this paper. Of the five NCs developed (NR/MWCNT-0, NR/MWCNT-3, NR/MWCNT-6, NR/MWCNT-9, NR/MWCNT-12 and NR/MWCNT-15), NR/MWCNT-3 (3 g of MWCNT in 100 g of natural rubber) showed the highest thermal stability of 260 °C, optimal water absorption rate of 0.1% and highest quality energy storage and dissipation capacity, as indicated by 2.239 DMA loss factor curve amplitude, hence giving it a comfortable edge over its existing counterparts. The results of the various analyses carried out indicated, therefore, that reinforcing natural rubber with multi-walled carbon nanotube offers a reliable alternative material for the prosthetic industry.

Preparation and Characterization of Reduced Graphene Oxide Based Natural Rubber Nanocomposites

Abstract This work describes the effect of reduced graphene oxide (RGO) addition in natural rubber (NR). Firstly, RGO was synthesized based on the improved Hummer's method then characterized by Fou...

Toughening of natural rubber nanocomposites by the incorporation of nanoscale lignin combined with an industrially relevant leaching process

Strong and tough nanocomposite materials based on natural rubber (NR) latex demonstrate increasing potential to be used in advanced engineering applications and personal care products. Among many approaches for improving the toughness of NR-based products, the use of renewable and bio-based nanofillers is persuaded by environmental and economic trends. In this study, we report the preparation and incorporation of nanoscale organosolv lignin (OSL) particles in NR latex to improve its mechanical properties. We showed that the tensile strength, toughness, and Shore hardness of NR films reinforced with 5 wt % nanoscale OSL were improved by 39 %, 53 % and 12 %, respectively, while retaining high elongation at break (∼1800 %). This substantially improved mechanical property profile can be attributed to the enhanced nanoscale dispersion of OSL and the associated favourable interfacial adhesion of OSL with the NR matrix. Furthermore, the impact of an industrially applicable leaching process on the toughness and thermo-oxidative stability of rubber films is also discussed. For an instance, after the leaching process, the tensile strength, elongation, and toughness of 1 wt % OSL/NR were increased by 27 %, 9 %, and 32 %, respectively.

Preparation and Characterization of Reduced Graphene Oxide Based Natural Rubber Nanocomposites

Abstract This work describes the effect of reduced graphene oxide (RGO) addition in natural rubber (NR). Firstly, RGO was synthesized based on the improved Hummer’s method then characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) to confirm that the RGO surface contains hydroxyl, epoxy, and carboxyl functional groups to improve graphene interaction with the NR matrix. In a second step, the synthesized RGO was predispersed in NR latex using the co-coagulation technique then added at different amounts (0 to 2 parts per hundred rubber (phr)) to a basic NR formulation and compounded in an internal mixer. The results show that the crosslink density of the developed NR/RGO nanocomposites increased by 65% for RGO concentration of 2.0 phr. For the same RGO concentration, a significant increase in tensile strength (53%) and Young’s modulus (31%) were also observed. Finally, a significant improvement (26%) of the thermal conductivity was obtained with the addition of only 0.5 phr of RGO.

Studies on natural rubber nanocomposites by incorporating amine functionalised graphene oxide

ABSTRACT The present study reports the synthesis of amine functionalised Graphene Oxide by two different methods, one by a modified Bucherer reaction and the other by using dodecyl amine. The synthesised amine functionalised Graphene oxide by modified Bucherer reaction (AGO) and by using dodecyl amine (DGO) was characterised by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Raman spectroscopy. A series of natural rubber (NR)-AGO and NR-DGO nanocomposites with varying compositions of AGO and DGO were prepared by the latex mixing method. The morphological, mechanical, and dielectric properties of the nanocomposites were analysed by SEM, TEM, universal testing machine (UTM), and impedance analyser. The results obtained for NR-AGO and NR-DGO nanocomposites revealed enhancement in mechanical and dielectric properties from neat NR and NR-Graphene Oxide (GO) nanocomposites. The tensile strength of NR has been improved by almost 70%, tensile modulus (300% elongation) by 85%, and tear strength by 67% on the addition of 0.5 phr of AGO and by the addition of 0.5 phr DGO, the tensile strength of NR has been improved by 74%, tensile modulus (300% elongation) by 87% and tear strength by 73%.

Studies on natural rubber nanocomposites by incorporating zinc oxide modified graphene oxide

To obtain an efficient performance of the natural rubber/graphene oxide nanocomposites, it is essential to enhance the interfacial interaction between the filler and the polymeric matrix. The present study aims to improve the interfacial interaction between natural rubber (NR) and graphene oxide (GO) by modifying GO with zinc oxide nanoparticles (ZGO) using the coprecipitation method. The structural and morphological properties of ZGO nanocomposites were characterised by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, UV–visible spectrophotometry (UV–vis), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). The characterisation results show that zinc oxide (ZnO) nanoparticles were synthesised and randomly decorated on the surfaces and edges of GO sheets. A series of NR-ZGO nanocomposites with varying compositions of ZGO were prepared by the latex mixing method. The morphological, mechanical, and dielectric properties of the nanocomposites were analysed by SEM, UTM, and impedance analyser. The results obtained for NR-ZGO nanocomposites revealed enhancement in mechanical and dielectric properties from neat NR and NR-GO nanocomposites.