Rubber-filler Interaction Research Articles

Fabrication of High-Performance Natural Rubber Composites with Enhanced Filler-Rubber Interactions by Stearic Acid-Modified Diatomaceous Earth and Carbon Nanotubes for Mechanical and Energy Harvesting Applications.

Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites made of stearic acid-modified diatomaceous earth (mDE) and carbon nanotubes (CNTs). The obtained mechanical properties were significantly better than those of unfilled rubber. Compared to pristine diatomaceous earth, mDE has higher reinforcing efficiencies in terms of mechanical properties because of the effective chemical surface modification by stearic acid and enhanced filler-rubber interactions. The addition of a small amount of CNT as a component in the hybrid filler systems not only improves the mechanical properties but also improves the electrical properties of the rubber composites and has electromechanical sensitivity. For example, the fracture toughness of unfilled rubber (9.74 MJ/m3) can be enhanced by approximately 484% in a composite (56.86 MJ/m3) with 40 phr (per hundred grams of rubber) hybrid filler, whereas the composite showed electrical conductivity. At a similar mechanical load, the energy-harvesting efficiency of the composite containing 57 phr mDE and 3 phr CNT hybrid filler was nearly double that of the only 3 phr CNT-containing composite. The higher energy-harvesting efficiency of the mDE-filled conductive composites may be due to their increased dielectric behaviour. Because of their bio-based materials, rubber composites made by mDE can be considered eco-friendly composites for mechanical and energy harvesting applications and suitable electronic health monitoring devices.

Investigating the impact of nanoparticle geothermal silica loading on the mechanical properties and vulcanization characteristics of rubber composites

The present study investigates the effects of nanoparticle geothermal silica (NGS) on the mechanical properties and vulcanization characteristics of rubber compounds with various filler loadings. The rubber compounds were filled with 0, 20, 30, and 40 phr of silica. The properties of NGS were analyzed using transmission electron microscopy, particle size analyzer, and BET surface area analysis to examine its morphology, size distribution, and surface area. The mechanical properties and vulcanization characteristics of the rubber compounds reinforced with NGS were evaluated using a universal testing machine and moving die rheometer. The results showed that NGS possessed the primary particle sizes below 20 nm and a surface area of 168.35 m2/g. The interaction between silica and rubber determined the modulus of the rubber composites and the vulcanization characteristics. The tensile strength of the rubber compounds, meanwhile, showed a significant increase more than threefold as the filler loading increased from 0 phr to 30 phr, followed by a slight decline at 40 phr loading. The addition of 20 phr of silica led to a prolonged scorch time compared to the filler-free compound due to the adsorption of activators and accelerators. However, the scorch time decreased after reaching 30 phr of silica loading, which could be attributed to the higher amount of bound rubber covering a portion of the silica surface, thereby reducing its ability to adsorb the activator. The presence of silica with good thermal conductivity enabled a better heat transfer during the vulcanization process, resulting in shorter curing times for higher loading. Rubber compounds with an NGS loading of 30 phr demonstrated a favorable balance between filler-rubber interactions, vulcanization characteristics, and mechanical properties in the rubber compounds.

Optimized End Functionality of Silane-Terminated Liquid Butadiene Rubber for Silica-Filled Rubber Compounds.

As the world is shifting from internal combustion engine vehicles to electric vehicles in response to environmental pollution, the tire industry has been conducting research on tire performance to meet the requirements of electric vehicles. In this experiment, functionalized liquid butadiene rubber (F-LqBR) with triethoxysilyl groups at both ends was introduced into a silica-filled rubber compound as a substitute for treated distillate aromatic extract (TDAE) oil, and comparative evaluation was conducted according to the number of triethoxysilyl groups. The results showed that F-LqBRs improved silica dispersion in the rubber matrix through the formation of chemical bonds between silanol groups and the base rubber, and reduced rolling resistance by limiting chain end mobility and improving filler-rubber interaction. However, when the number of triethoxysilyl groups in F-LqBR was increased from two to four, self-condensation increased, the reactivity of the silanol groups decreased, and the improvement of properties was reduced. As a result, the optimized end functionality of triethoxysilyl groups for F-LqBR in silica-filled rubber compound was two. The 2-Azo-LqBR with the optimized functionality showed an improvement of 10% in rolling resistance, 16% in snow traction, and 17% in abrasion resistance when 10 phr of TDAE oil was substituted.

Precise role of zirconia to boost up the mechanical, thermal, viscoelastic, dielectric, and chemical resistance properties of natural rubber-nitrile rubber blend

Silica and other metal oxides have been emerged as potential substitutes of conventional carbon black (CB) to reinforce elastomeric materials. It not only steers clear of the ill-effects of CB such as issues like carcinogenicityand carbon footprint but they can impart rich thermal, optical, dielectric, and antimicrobial properties to the composites in addition to appreciable reinforcement. Silica is of special mention in this context while titania and zirconia to follow next. In this work, we report efficacy of zirconia towards property enhancement of a rubber blend comprised of non-polar natural rubber (NR) and polar nitrile rubber (NBR). Designed and controlled incorporation of zirconia in rubber matrix via an in-situ approach offers appreciable reinforcement to the composites. This is due to the fine dispersion of zirconia in elastomer matrix (SEM), efficient rubber-filler interaction (DMA) and increased crosslinking densities (swelling study). Analysis by atomic force microscopy (AFM) and differential scanning calorimetry (DSC) indicates that in-situ zirconia acts in favour of improved blend compatibility as well. All these factors offer notable impact on the other composite properties viz. improved thermal stability, enhanced flame retardancy and excellent chemical resistance to the blend composites. Additionally, dielectric properties become better upon incorporation of in-situ zirconia. The enhancement of composite properties becomes more prominent upon surface modification of in-situ zirconia by an organosilane Bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT). Superiority of in-situ zirconia over externally filled zirconia has been established by a comparative analysis. Hence, current study offers valuable insights on the potential of in-situ zirconia as a substitute of CB to reinforce the rubber blends. The findings have important implications for the development of high performance elastomeric composites that can sustain in harsh service conditions.

Fill two needs with one deed: Simultaneous devulcanization and silica reinforcement of waste rubber for green tyre tread compound

The proper disposal of waste rubber without disturbing the environment is one of the most challenging tasks towards the researchers and scientists in the 21st century. The existing disposal techniques other than recycling of waste rubber goods, does not add any value either on the waste polymeric material or in the raw material from which those polymeric materials are originated. The mechanochemical devulcanization of waste natural rubber by bis(3-triethoxysilylpropyl)tetrasulfide and its subsequent dispersion in fresh natural rubber-silica composites in various proportions ranging from 20% to 70% wt% are both addressed in this investigation. The mechanical performance of the composites clearly indicates that tensile strength, tear strength and elongation at break gradually increases with increasing devulcanized rubber (r-NR) content up to a certain proportion and the values are much superior to that of the control formulation. The evaluated mechanical properties clearly specify that the optimum level of r-NR in the composite is 40 phr. The developed green composites showed superior thermal behavior compared to that of its control formulation. The rubber filler interaction between devulcanized natural rubber (r-NR) and silica was further explored by measuring the fraction of immobilized polymer chains using differential scanning calorimetry. Scanning electron microscopic images (SEM) of the r-NR based NR/r-NR/SiO2 composites reveal a homogeneous and uniform dispersion of the silica filler.

Recycling waste polyurethane from the refrigeration industry as filler in SBR/NR composites for industrial applications

AbstractThe refrigeration industry produces millions of tons of waste polyurethane (PU) every year, which can cause environmental damage and human health problems. This article analyzes the use of waste PU as filler in composites made of styrene butadiene rubber (SBR) and natural rubber (NR) to produce shoe soles. The interfacial interaction of said filler was evaluated by the Flory–Rehner method (swelling) using the equation developed by Lorenz–Park. The results of this evaluation were later compared with those obtained by the Mooney–Rivlin method using the data from stress–strain tests. According to the results of the tensile strength tests, the composites filled with waste PU present stress–strain curves that are like those of metallic materials that have low elastic strength but high plastic strength. Using the Lorenz–Park equation, the filled composites examined in this study exhibited values above 0.7, which means a strong filler–rubber interaction. Scanning Electron Microscopy and Fourier‐Transform Infrared Spectroscopy were used to investigate the morphology of the composites in detail.

Characterization of recycled end-of-life rubber tire filled with black slag

To date, discarded tires are reused in many applications, however, because of the enormous quantity decommissioned annually, it is essential to continue researching new recycling methods as well as applications to reduce waste and preserve new resources. In the present study, a simple recycling technology of end-of-life tire (ELT) powder is proposed, and the influence of steel slag as filler is assessed. Europe produces about 7 Mt of steel slag annually, and although most of it is reused as an artificial aggregate, about 15% is still landfilled. Also in the case of steel slag, the study of new applications is mandatory so that the combination of these two waste materials, in a 100% recycled composite fits across different industrial sectors facing the same environmental issue. It was found that the leaching of the slag incorporated in the rubber matrix is reduced and that the ELT powder recycled by this technology gives rise to a well-cohesive material. A good rubber-filler interaction was found by swelling test and differential scanning calorimetry (DSC) analysis. The slag reduces the friction coefficient and increases the thermal conductivity. The experimental results showed how some properties of recycled ELT can be improved by adding the steel slag.

Utilization of palm oil as an alternative processing oil in carbon black-filled natural rubber compounds

Due to the toxicity of distillate aromatic extract (DAE), palm oil (PO) being environmental friendliness, renewability, and sustainability, was used as an alternative processing oil in this study. The properties of carbon black-filled natural rubber compounds containing PO were investigated and compared with the DAE-added rubber compound. The results revealed that the presence of PO in the rubber compound gave the same degree of filler–filler interactions but higher filler-rubber interactions compared with the one with DAE. Payne effect as referred to filler-filler interactions of the rubber compounds with DAE and PO was 191 and 189 kPa, respectively. In addition, the presence of PO not only accelerated the vulcanization reaction but also reduced the crosslink density within the rubber matrix. The crosslinking type of PO-added rubber compounds consisted only of polysulfidic linkages, whereas the DAE-added rubber compound contained various crosslinking types, i.e., mono-, di-, and polysulfidic linkages. On the other hand, the presence of PO in rubber compounds promoted a positive effect on elastic properties, as indicated by the temperature scanning stress relaxation (TSSR) index and tan δ at 60 °C. The TSSR index of rubber compounds with DAE and PO was 0.69 and 0.71, respectively. Given the low tan δ at 60 °C of the PO-added rubber compounds, PO promoted a low rolling resistance when applied in tire applications, providing tires with safe energy.

Effect of Alumina Modified by Silane on the Mechanical, Swelling and Dielectric Properties of Al2O3/EPDM/SBR Blend Composites

Rubber blending has been widely used to improve various properties in finished rubber products. The purpose of this paper is to investigate the effect of filler size, type, concentration, and surface treatment on the mechanical, swelling, dielectric, and morphology properties of ethylene propylene diene rubber (EPDM)/styrene-butadiene rubber (SBR) rubber blend nanocomposites filled with alumina (Al2O3) nanoparticles. Bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT) was used as a silane coupling agent. Rubber blend nanocomposites containing Al2O3 nanoparticles were compared to carbon black (CB). The results indicate that the nanocomposites prepared, in particular with the TESPT, had better properties than the composites without the TESPT. Mechanical properties of the CB-filled EPDM/SBR rubber blend were noticeably improved, indicating CB's inherent reinforcing potential. We found that rubber nanocomposites' crosslink density and filler–rubber interaction increase, and the swelling coefficient decreases with increasing filler content. The dielectric properties of the nanocomposites showed a significant enhancement with fillers. SEM images showed that the CB sample had a higher distribution than Al2O3 due to good interaction and dispersion. This study's experimental data will help design and manufacture outdoor insulators.

A new testing strategy based on the wetting concept for characterizing rubber-filler interaction in rubber compounds and its application to the study of the influence of epoxy groups and non-rubber components on rubber-filler interaction in natural rubber compounds

A new testing strategy based on the wetting concept for characterizing rubber-filler interaction in rubber compounds and its application to the study of the influence of epoxy groups and non-rubber components on rubber-filler interaction in natural rubber compounds

Structural analyses of the bound rubber in silica-filled silicone rubber nanocomposites reveal mechanisms of filler-rubber interaction

Although the reinforcing effect of fumed silica on silicone rubber is always better than that of precipitated silica, their enhancement mechanism is still controversial due to the cognitive defects of the interface effect and filler network effect of polymer nanocomposites with the limited experimental study. Herein, significant entanglement network structure differences were revealed in the fumed and precipitated silica-filled phenyl silicone rubber by removing the physisorbed rubber gradually via 90 °C-ultrasonic solvent extraction method, which eventually obtained tightly bound rubber to explain filler-rubber interaction. The silica wrapped by tightly bound rubber was observed by SEM and TEM, where fumed silica is entangled with tightly bound rubber to robust dendritic structure, while precipitated silica is entangled with tightly bound rubber to the irregular agglomerate structure. Low-field 1H NMR confirmed that the mobility of the tightly bound rubber was significantly lower than loosely bound and free rubber. Furthermore, during the US treatment, the Si–O–Si infrared peaks of fumed silica-filled rubber exhibited "blueshift-redshift-blueshift" while the precipitated silica one only "blueshift" appears, which directly confirmed that different nanoporous structures of nanofiller induced diversity of filler-rubber entanglement network. The tightly bound rubber of precipitated silica (16.71%) was much more than that of fumed silica (3.72%) (40 phr). Although fumed silica adsorbs less tightly bound rubber than precipitated silica, the prominent nanofiller networks formed by fumed silica-rubber greatly enhanced the Payne effect and damping properties. This work can help to deeper understand the formation of the filler-rubber entanglement network and its contribution to the physical properties.

Understanding the Reinforcement Effect of Fumed Silica on Silicone Rubber: Bound Rubber and Its Entanglement Network

In this work, fumed silica was compounded with silicone rubber and processed under two different extraction conditions to quantitatively analyze bound rubber for studying filler–rubber interaction. When nanocomposites were treated with toluene at 90 °C under ultrasonic (US) irradiation, physisorbed polymer chains were more substantially removed when compared to the traditional room temperature (RT) extraction method. The bound rubber fraction of silicone rubber filled with 40 phr of silica was 32.85% by RT treatment, while the US-treated one was reduced to 6.20%. A thin layer of tightly bound rubber adsorbed on the silica surface could be obtained by US treatment as observed by scanning electron microscopy and transmission electron microscopy. Low-field 1H NMR results confirmed that the obtained tightly bound rubber chains were strongly constrained. The attenuated total reflectance-infrared spectra showed that the formation of tightly bound rubber caused redshift of the Si–O–Si characteristic peaks of silica, and the obtained tightly bound rubber has lower total surface energy than the rubber matrix, indicating the formation of a more stable structure. The reagglomeration potential energy of silica during the curing process was significantly reduced due to the presence of the bound rubber layer. In addition, the amount of tightly bound rubber is mainly related to the surface physical and chemical properties of silica and is less affected by the concentration. Fumed silica tends to form nanofiller networks in rubber that are woven of multiple fillers entangled with bound rubber chains to reinforce the rubber. Therefore, fillers with higher bound rubber content and a better-dispersed aggregate structure in the rubber could more significantly enhance the physical properties of nanocomposites.

Improvement of nanosilica effects on the performance of mechanically processed styrene-butadiene rubber by rational hybridization with nanodiamond

Hybrid nanoparticle comprising of nanosilica (NS) and nanodiamond (ND), denoted by [email protected], was synthesized by a two-step chemistry route and then incorporated into styrene-butadiene rubber (SBR) at low concentrations up to 5 phr by a two-roll mill. Physical hybrids of NS and ND, i.e., ND&NS, with a weight ratio similar to chemical hybrid (80:20 for NS:ND), were also incorporated into SBR. Field emission scanning electron microscopy observations revealed very fine dispersion of nanoparticles in the case of physical hybrids (ND&NS). In contrast, agglomerations and aggregation of nanoparticles were evidenced for [email protected] Tensile and dynamic mechanical analyses exhibited a higher reinforcing effect of hybrid nanoparticles with respect to single nanoparticles; however, ND&NS showed even better performance compared with [email protected] due to better filler-rubber interaction caused by improved filler dispersion. So, tensile strength, elastic modulus, and elongation at break of unfilled SBR increased about 23 %, 40 %, and 110 %, respectively, in the case of ND&NS. It was also realized that the incorporation of [email protected] and ND&NS, both at 5phr, enhanced the thermal conductivity of SBR by around 46 % and 31 %, respectively, with slightly better influence of [email protected] on thermal conductivity due to the improvement of the phonon energy transfer mechanism in this case.

Research on Dynamic Mechanical Properties of Different Silane Coupling Agent In-situ Modified SSBR/Silica Composites

Hydroxyl density of silica surface will reduce and the compatibility of silica with rubber matrix will be improved through the modification of silica by silane coupling agent (SCAs). The silica-silica and silica-rubber interaction of silica filled solution polymerized styrene butadiene rubber (SSBR) in-situ modified by silane coupling agent TESPT and Si747 are studied by Dynamic Mechanical Analyzer (DMA). The effect of different types and loading amounts of SCAs on the dynamic mechanical properties of silica filled SSBR is investigated. The results show that the novel silane coupling agent Si747 has a more apparent effect on lessening the silica network than that of silane coupling agent TESPT, Hysteresis factor (tanδ) measured by DMA reduces, and the heat-built improves. It could also be found that Si747 modified composites have the lowest apparent activation energy, which is used to characterize the filler-rubber interaction, indicating the lowest temperature dependence.

Ferric Ions Crosslinked Epoxidized Natural Rubber Filled with Carbon Nanotubes and Conductive Carbon Black Hybrid Fillers.

Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe3+) as a crosslinking agent. The ENRs filled exclusively with CNTs, and CNT–CCB hybrid fillers exhibited typical curing curves at different CCB loadings, i.e., increasing torque with time and thus crosslinked networks. Furthermore, the incorporation of CNT–CCB hybrid fillers and increasing CCB loadings caused an enhancement of tensile properties (modulus and tensile strength) and crosslink densities, which are indicated by the increasing torque difference and the crosslink densities. The crosslink densities are determined by swelling and temperature scanning stress relaxation (TSSR). Increasing CCB loadings also caused a significant improvement in bound rubber content, filler–rubber interactions, thermal resistance, glass transition temperature (Tg) and electrical conductivity. A combination of 7 phr CNT and CCB with loading higher than 2.5 phr gave superior properties to ENR vulcanizates. Furthermore, the secondary CCB filler contributes to the improvement of CNT dispersion in the ENR matrix by networking the CNT capsules and forming CNT–CCB–CNT pathways and thus strong CNT–CCB networks, indicating the improvement in the tensile properties, bound rubber content and dynamic properties of the ENR composites. Moreover, higher electrical conductivity with a comparatively low percolation threshold of the hybrid composites was found as compared to the ENR filled with CNTs without CCB composite. The superior mechanical and other properties are due to the finer dispersion and even distribution of CNT–CCB hybrid fillers in the ENR matrix.

Effect of black sand nanoparticles on physical-mechanical properties of butyl rubber compounds

A novel type of silica namely black sand (BS) with silane coupling agent was chosen as reinforcing filler in butyl rubber (IIR). BS was obtained from the beach area of Rosetta in Egypt. The filler was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM). The XRD analysis showed that BS is composed mainly of Albite (Sodium Aluminium Silicate) up to 64% approximately. Novel nanocomposites were prepared via a two-roll mill by incorporating different concentrations of BS nanoparticles (5,10, 15, 20,30 and 40 phr) in IIR. The effects of filler loading on shape factor, curing characteristics, and mechanical and dynamic properties of IIR vulcanizates were investigated. The modulus of IIR vulcanizates was used to predict the shape factor of BS aggregation in the polymer. The data indicated that cure time decreased with the increase in filler loading, and the change in scorch time is less. It was found that the shape factor is independent of the concentration. With an increase in the filler loading, tensile and elongation of the composites were significantly increased, especially at 30 phr. The bound rubber content increased with increasing BS content up to 30 phr exhibiting the rubber-filler interaction. The reinforcing factor, R (related to the difference in tan δ peak height at the glass transition temperature (Tg) for the filled and unfilled rubbers), also demonstrated that the BS-IIR interaction was stronger than for unfilled rubber. Since 30 phr black sand loaded IIR composite showed superior physical-mechanical properties. In general, the results indicated that the black sand filler was an effective reinforcement material for the butyl rubber.

The Effects of Carbon-Silica Dual-Phase Filler on the Crosslink Structure of Natural Rubber.

Carbon–silica dual-phase filler (CSDPF)/natural rubber (NR) vulcanizate was prepared by mechanical blending, followed by a hot-press vulcanization. The dispersion of CSDPF in the NR matrix and the effects of CSDPF on the filler–rubber interaction and structure of the rubber network were studied. Scanning electron microscope results showed that CSDPF dispersed uniformly; however, there were some aggregates of CSDPF when loading too many fillers. With an increase in CSDPF, the interaction between CSDPF and NR chains increases, which was detected by bound rubber in the CSDPF/NR compound. The spectra of solid-state nuclear magnetic resonance revealed that CSDPF could promote the formation of poly-sulfidic crosslink in the rubber vulcanization network. Further, the molecular chain movement ability of vulcanizates decreases according to the spin–spin relaxation of 1H nuclei in CSDPF/NR compounds. The crosslink density of vulcanizate increases, while the chemical crosslink and physical crosslink in the vulcanization network also increase according to the tube model.

Protein-based biochars as potential renewable fillers in styrene-butadiene rubber composites

In this study, chicken feather meal (CFM) and canola protein (CP) were converted into biochar and their suitability as reinforcing fillers in styrene-butadiene rubber (SBR) composites was evaluated. The protein-based feedstocks were pyrolyzed at 700 °C for 1 h, at a heating rate of 50 °C/min under different pyrolysis atmospheric conditions (N2, CO2, and steam). The flow rate of N2 and CO2 was 700 ml/min, while that of steam was 31 ml/min. Also, biochar was produced under N2 and CO2 gas flow and subsequently activated using steam. The physicochemical properties of the resulting CFM and CP biochars were characterized based on elemental and proximate analyses, surface area, Fourier-transform infrared spectroscopy (FTIR), and thermal field emission scanning electron microscopy. Results showed that activated CP, pyrolyzed under nitrogen and subsequently steam cooled (CP N2 + SC), had enhanced physicochemical properties such as lower ash content, higher fixed carbon content, and reduced polar surface functional groups compared to the other studied biochars in this study. Results also showed that CFM and CP pyrolyzed under nitrogen and subsequently steam cooled displayed higher final moduli and better filler dispersion in rubber than the other biochar samples produced in this study. Given that results showed favorable physicochemical properties and higher final moduli for CP N2 + SC, this sample was further tested using dynamic mechanical analysis (DMA) and results showed slight differences with carbon black regarding the temperature dependence of the shear storage modulus (G′) and the loss tangent (tan δ). These differences were attributed to increased filler-filler interactions, reduced filler-rubber interactions, and a lower dispersion in rubber than carbon black. The observed differences were not large enough to explain the inability of the biochar to adequately reinforce the rubber. However, the biochar filled rubber sample had a comparable viscoelastic behavior to carbon black over the studied temperature range.

Mechanical and magneto-mechanical properties of styrene-butadiene-rubber-based magnetorheological elastomers conferred by novel filler-polymer interactions

This study was undertaken to explore the mechanical and magneto-mechanical properties of styrene butadiene rubber (SBR) based magnetorhelogical elastomers (MREs) reinforced with carbonyl iron particles (CIP) as a primary filler. Nanocarbon materials such as nano carbon black (NCB) and few layer graphene (FLG) were used as secondary fillers to reinforce the rubber matrix. The key purpose of this study is to demonstration how the mechanical and magneto-mechanical properties of MREs are related with filler-rubber interactions. CIP can reinforce rubber, although it contains micron size particles, and improvements in moduli and fracture toughness values indicate the formation of filler-rubber networks and interactions between the π-electrons of benzene and the d-orbital electrons of iron. Optimization of CIP filler loadings in SBR was performed using mechanical properties. Tensile strength and elongation at break were increased by increasing CIP loadings up to 15 vol%, and the addition of FLG at 2 vol% further improved mechanical and magneto-mechanical properties as compared with 17 vol% CIP in SBR-based MREs. The study shows that the addition of nano reinforcing filler and an optimum amount of magnetic filler enhances magnetic and mechanical properties, which would be useful for high-energy smart damping systems.

Preparation and reinforcement performance of RGO-CNTs-SiO2 three-phase filler for rubber composites

Rubber reinforcement technology is developing towards the direction of high efficiency and multi-functionality, and the reinforcement of rubber by a single-component filler can no longer meet the requirements. Nanocomposite fillers have become the development trend of high-performance reinforcing fillers due to the complementary advantages and synergistic reinforcing effects of each component. Reduced graphene oxide-carbon nanotubes (RGO-CNTs) composites were prepared by a method of electrostatic assembly. The non-covalent modified RGO-CNTs was used as a substance to grow in situ SiO2 nanoparticles (RGO-CNTs-SiO2), and the RGO-CNTs-SiO2 three-phase fillers were obtained. The RGO-CNTs-SiO2 three-phase fillers were further used to study the reinforcing properties of hydrogenated nitrile rubber (HNBR). Furthermore, the effects of RGO-CNTs-SiO2 with different component contents on the reinforcing properties of HNBR were systematically studied. The TEM images of RGO-CNTs-SiO2 show that the RGO and CNTs promotes mutual dispersion, and the SiO2 nanoparticles (average diameter 7 nm) are highly dispersed on the surface of RGO-CNTs. The characterization of RGO-CNTs-SiO2/HNBR indicates that the RGO-CNTs-SiO2 efficiently weaken the filler network and improve the filler-rubber interaction. The results show that the three-phase fillers produce obvious synergistic reinforcing effects. The highest tensile strength (30.1 MPa) of RGO-CNTs-SiO2/HNBR is achieved at the RGO:CNTs mass ratio of 1:5, the RGO-CNTs mass percentage of 2%, and the filler loading of 50 phr. This work demonstrates the considerable promise for developing three-phase filler-based rubber composites.