Parts Of Rubber Research Articles

Effect of Short Banana Fiber on Hardness and Tensile Properties of Natural Rubber Composites

Banana fiber (BF) was utilized as a reinforcing filler for natural rubber (NR). BF/NR composites containing banana fiber contents of 5, 10, and 15 parts per hundred parts of rubber (phr) were mixed on a two-roll mill machine. The hardness, tensile properties of BF/NR composites were studied. It was found that the hardness and moduli of BF/NR composites are higher than that of NR. Despite tensile strength and strain at break of BF/NR composite lower than NR. Moreover, hardness and moduli of BF/NR composites increased, while tensile strength and strain at break decreased with the increase in banana fiber content. Thus, banana fiber exhibited improvement in the stiffness significantly of NR composites

Effect of particle size of leather wastes on the processing, vulcanization, and physico-mechanical properties of natural rubber/leather wastes composites

In this work, the effect of particle size and the content of leather wastes on the processability, vulcanization, and mechanical properties of a natural rubber/leather wastes composites was studied. From a reduction process, leather waste was later sieved to classify particles smaller than 0.6 mm and particles between 0.84 and 2 mm, hereafter called fine and coarse residues, respectively. The morphology of the wastes was analyzed from scanning electron microscopy micrographs. Natural rubber/leather wastes composites with 20, 40, 60, 80, and 100 phr (parts per 100 parts of rubber) of treated leather wastes were obtained in a torque rheometer. Mixtures with coarse wastes exhibited a slightly higher torque than mixtures with the fine wastes; additionally, increasing the wastes content yields in an increased torque during the final stage of the process. The addition of leather wastes increased the vulcanization time and stiffness of the composites; additionally, materials with fine wastes showed lower vulcanization times compared to materials with coarse wastes. Composites with fine leather wastes exhibited higher density and tensile modulus than materials with coarse wastes; however, only the composites with 80 and 100 phr of wastes showed a statistically significant difference in hardness values. The specific energy consumption (SEC) was calculated from the results obtained with the torque rheometer; it was found that for all the formulations the SEC decreased as the phr of leather residues increased. It was found that it is possible to use leather wastes in natural rubber composites, to obtain adequate materials feasible for some applications.

Manifestation of the silicate filler additives and electron beam irradiation on properties of SBR/devulcanized waste tire rubber composites for floor tiles applications

AbstractVirgin styrene‐butadiene rubber (SBR) was replaced by devulcanized waste tire rubber (DWR) 50/50 and used as a rubber base for preparing composites to depend on different silicate types at fixed content 40 phr (part per hundred part of rubber). All composites were mixed on a rubber roll mill and then subjected to electron beam irradiation to induce cross‐linking at a dose of 100 kGy. Different silicate fillers were used in this study such as precipitated silica (PS) 40 phr, waste glass window (WG) – PS 20/20 phr, fly ash (FA)‐PS 20/20 phr, and micaosilica (MS)‐PS 20/20 phr. Waste silicate was treated with (3‐aminopropyl) trimethoxysilane (APTMS) and blended with PS. Mechanical properties were measured for the composites like ultimate tensile strength, elongation at break, tensile modulus, and the cross‐link density was calculated from the mechanical study. As well as, application for floor tiles included compression set and abrasion resistance measurements. All results indicated an enhancement in ultimate tensile strength, modulus, and cross‐link density by adding silicate fillers and more enhanced in the electron beam irradiated samples. For the application of floor tiles, the MS filler gave a good compression set and abrasion resistance followed by other silicate fillers (PS, FA), except WG.

Significantly reinforced and long serviceable acrylonitrile butadiene rubber/graphitic carbon nitride composites for future industrial applications

The application of graphitic carbon nitride (g-C3N4) as non-black reinforcing filler is very little-known part in rubber technology. In the present study, g-C3N4 filled acrylonitrile butadiene rubber (NBR) composites were prepared by conventional two-roll milling process to investigate the influence of g-C3N4 on the mechanical and thermal performances of NBR formulations. NBR composite with 3 phr (parts per hundred parts of rubber) g-C3N4 presents considerably higher cure rate index, hardness, tensile strength, storage modulus and thermal stability than unfilled NBR composite. Also, the addition of g-C3N4 successfully enhances the thermal oxidative aging resistance and fuel consumption efficiency of NBR composites. Thus, g-C3N4 can be used in the near future as interesting filler for developing long serviceable NBR composites with good mechanical properties.

Silicone Rubber Composites Reinforced by Carbon Nanofillers and Their Hybrids for Various Applications: A Review.

Without fillers, rubber types such as silicone rubber exhibit poor mechanical, thermal, and electrical properties. Carbon black (CB) is traditionally used as a filler in the rubber matrix to improve its properties, but a high content (nearly 60 per hundred parts of rubber (phr)) is required. However, this high content of CB often alters the viscoelastic properties of the rubber composite. Thus, nowadays, nanofillers such as graphene (GE) and carbon nanotubes (CNTs) are used, which provide significant improvements to the properties of composites at as low as 2–3 phr. Nanofillers are classified as those fillers consisting of at least one dimension below 100 nanometers (nm). In the present review paper, nanofillers based on carbon nanomaterials such as GE, CNT, and CB are explored in terms of how they improve the properties of rubber composites. These nanofillers can significantly improve the properties of silicone rubber (SR) nanocomposites and have been useful for a wide range of applications, such as strain sensing. Therefore, carbon-nanofiller-reinforced SRs are reviewed here, along with advancements in this research area. The microstructures, defect densities, and crystal structures of different carbon nanofillers for SR nanocomposites are characterized, and their processing and dispersion are described. The dispersion of the rubber composites was reported through atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effect of these nanofillers on the mechanical (compressive modulus, tensile strength, fracture strain, Young’s modulus, glass transition), thermal (thermal conductivity), and electrical properties (electrical conductivity) of SR nanocomposites is also discussed. Finally, the application of the improved SR nanocomposites as strain sensors according to their filler structure and concentration is discussed. This detailed review clearly shows the dependency of SR nanocomposite properties on the characteristics of the carbon nanofillers.

Mechanical and magnetic response of magneto‐rheological elastomers with different types of fillers and their hybrids

AbstractThe use of secondary reinforcing fillers such as graphene or multi‐wall carbon nanotube (CNT) for improving mechanical properties is an effective strategy to obtain high performance magneto‐rheological elastomers (MREs). Therefore, MREs were prepared via solution mixing of room‐temperature‐vulcanized silicone rubber (RTV‐SR) and iron oxide (Fe3O4), and hybridized with iron wire, Few‐layer graphene (FLG), and CNT as secondary nanofillers. The isotropic mechanical properties were studied through compressive tests, and their compressive moduli and reinforcing factors were determined. From these studies, it was found that CNT‐based hybrid MREs show the highest compressive mechanical properties. For example, at 80 per hundred parts of rubber (phr), the compressive modulus was 3.5 MPa (RTV‐SR/Fe3O4), 4.1 MPa (RTV‐SR/Fe3O4‐FLG), 5.5 MPa (RTV‐SR/Fe3O4‐CNT), and 3.7 MPa (RTV‐SR/Fe3O4‐iron wires). A nanofiller with higher aspect ratio (CNT), has a strong effect on the isotropic mechanical properties, whereas a lower aspect ratio nanofiller (FLG) has a greater effect on magnetic sensitivity. Although iron wires with lower specific surface areas can only improve the mechanical properties slightly, they can improve the magnetic sensitivity of MREs because of its stronger magnetic behavior.

Enhanced X-ray shielding properties of NRL gloves with nano-Bi2O3 and their mechanical properties under aging conditions

This work investigated X-ray shielding and the mechanical, morphological, and physical properties of natural rubber latex (NRL) gloves vulcanized using either a sulfur or gamma curing system, with the addition of varying nano-Bi2O3 contents from 50 to 200 parts per hundred parts of rubber by weight (phr) for potential use in the fabrication of lead-free X-ray-protective latex gloves. The results showed that the addition of nano-Bi2O3 fillers enhanced the X-ray shielding ability and density of the composites. The results also revealed that nano-Bi2O3 slightly increased the tensile modulus but decreased the tensile strength and elongation at break in both curing systems. Furthermore, 90–170 phr of nano-Bi2O3 provided the optimum contents that produced gamma-vulcanized natural rubber latex (GVNRL) gloves having both X-ray shielding and mechanical properties greater than the minimum requirements for commercial X-ray protective gloves and examination gloves (ASTM D3578-19). In addition, it was found that gamma and thermal aging affected the mechanical properties, with sulfur-vulcanized natural rubber latex (SVNRL) gloves having increased overall mechanical properties, while GVNRL gloves exhibiting lower properties. The overall results suggested that the developed GVNRL gloves had great potential for use as effective X-ray protective gloves with nano-Bi2O3 acting as a suitable X-ray protective filler.

Treasuring waste lignin as superior reinforcing filler in high cis-polybutadiene rubber: A direct comparative study with standard reinforcing silica and carbon black

There has been ever raising concern in last few decades about the utilization of biomass for different commercial applications such as filler materials in rubber composites. In this context, an interesting pathway has been proposed to develop such composites by introducing waste lignin as a reinforcing constituent in high cis-polybutadiene rubber (BR). With a judicious selection of rubber curing ingredients and, simultaneously, adopting suitable solid-state mixing protocols, particularly, a relatively high-temperature multi-steps melt-mixing process (above the glass transition temperature of lignin), rubber composites with an outstanding mechanical performance were prepared. The reinforced rubber composites with 50 (weight) parts lignin loading per hundred parts of rubber (phr) offer ∼10 MPa tensile strength (TS), ∼276% elongation at break (EB), and ∼3.51 MPa tensile stress at 100% elongation (so-called rubber modulus M100). These values are superior when compared with the composites comprised with standard reinforcing carbon black (∼8.5 TS, ∼224% EB, ∼2.79 M100) and even with a silica-silane system (∼7.34 TS, ∼229% EB, ∼2.44 M100) with same filler loading. The unique combination of the curing packages and four-stage mixing process allowed us to establish a homogeneous and fine dispersion of lignin. Furthermore, this is the first time that available models of rubber reinforcement are applied to the description of the reinforcement mechanisms of lignin in a soft elastomer involving various aspects like filler-filler interaction, rubber-filler interactions, critical strains for destroying the filler-filler network, effective filler volume fractions, shape factor, etc. The developed compounding methods for BR and their characterization and modeling can be easily applied to other commercial rubbers facilitating a real breakthrough in developing cheap and bio-based high-performance rubber composites.

Theoretical Determination of High-Energy Photon Attenuation and Recommended Protective Filler Contents for Flexible and Enhanced Dimensionally Stable Wood/NR and NR Composites.

This work aimed to theoretically determine the high-energy-photon-shielding properties of flexible wood/natural rubber (NR) and NR composites containing photon protective fillers, namely Pb, Bi2O3, or Bi2S3, using XCOM. The properties investigated were the mass attenuation coefficient (µm), linear attenuation coefficient (µ), and half value layer (HVL) of the composites, determined at varying photon energies of 0.001–5 MeV and varying filler contents of 0–1000 parts per hundred parts of rubber by weight (phr). The simulated results, which were in good agreement with previously reported experimental values (average difference was 5.3%), indicated that overall shielding properties increased with increasing filler contents but decreased with increasing incident photon energies. The results implied the potential of bismuth compounds, especially Bi2O3, to replace effective but highly toxic Pb as a safer high-energy-photon protective filler, evidenced by just a slight reduction in µm values compared with Pb fillers at the same filler content and photon energy. Furthermore, the results suggested that the addition of 20 phr wood particles, primarily aimed to enhance the rigidity and dimensional stability of Pb/NR, Bi2O3/NR, and Bi2S3/NR composites, did not greatly reduce shielding abilities; hence, they could be used as dimensional reinforcers for NR composites. Lastly, this work also reported the optimum Pb, Bi2O3, or Bi2S3 contents in NR and wood/NR composites at photon energies of 0.1, 0.5, 1, and 5 MeV, with 316–624 phr of filler being the recommended contents, of which the values depended on filler type and photon energy of interest.

Effect of Pre-Blending and Phase-Mixing Methods on Properties of Natural Rubber and Acrylonitrile Butadiene Rubber Blends Filled with Nano Silica Extracted from Rice Husk Ash

Properties of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) blends are varied due to blending method. The literature is evident that the pre-blending and phase-mixing methods affect the properties of blends while opposite arguments are also available. Hence, that fact was interested to study using NR/NBR blends filled with rice husk ash nano silica (RHANS) having an average particle size of 50 nm - 100 nm with some micro-scale agglomerates. The structure of RHANS was proved using X-ray diffraction and Fourier transform infrared spectrophotometric analyses. Blends were prepared following both blending methods by varying NR to NBR ratio as 0:100, 20:80, 40:60, 60:40, 80:20, and 100:0 while filling 25 parts per hundred parts of rubber of RHANS. The control was the ASTM formulation for oil seals. Vulcanization properties of blends showed acceptable levels with extended scorch and cure times and high torque properties. Blends indicated less tensile and tear strength compared to the control while showing acceptable hardness, compression set, and swelling properties. Overall, there is a possibility to use RHANS in NR/NBR blends and it was found that the blending method does not affect the properties of the NR/NBR blends.

Effect of titanium carbide powder as a filler on the mechanical properties of silicone rubber

Silicone rubber is the most commonly used polymer. The properties include high and low temperature stability, inertness, odourless, high elasticity, durability, electrical properties and transparency. Silicone rubber is composed of silicone polymer and molecules like carbon, hydrogen and oxygen. Recent times, some drawbacks like hardness, have emerged and there have been extensive efforts in research to improve its properties. This work is intended to study the effect of Titanium Carbide in particle form on the mechanical properties of Silicone Rubber. The amount of Titanium Carbide is 0, 1, 2 and 5 parts by weight per hundred parts of rubber [phr] taken in 4 samples. An experimental study has been conducted on all the samples to determine the mechanical properties of all the samples. The obtained results indicate the cure time increases at 1% TiC and reduces gradually, specific gravity increases constantly, tensile strength has maximum value at 1% TiC, tear strength shows its peak at 2% TiC, hardness of the samples increases gradually as the percentage of Titanium Carbide increases, elongation percentage has a peak value for 1% TiC sample.

Investigation of Physical and Mechanical Properties of Rubbers Reinforced by Carbon Nanostructured Components

The work presents investigation results of physical and mechanical properties of rubber mixtures based on SKI-3 and SKS-30-ARKM-15 rubbers reinforced with hybrid filler carbon black/carbon nanotubes (CB/CNT). Elasticity, hardness and strength were measured according to standard procedures presented in GOST. The content of the carbon nanotubes in rubber mixtures was 0,5 wt. %. parts per 100 wt. parts of rubber. According to experiments, it was found that the introduction of CB/CNT masterbatches into the structure of both investigated rubbers reduces their elasticity and increases Shore A hardness. During uniaxial tension of the tested rubbers, it was found that the presence of the nanostructured CB/CNT filler in the rubber structure leads to an increase in the nominal strength for SKI-3-based rubber by 19,6 %, and on SKS-30-ARKM-15 by 22,5 %. Therefore, the use of CB/CNT nanostructures as a rubber filler is a promising method of improving rubber performance characteristics.

Ablation and thermal properties of ethylene propylene diene rubber/carbon fiber composites cured by ionizing radiation for heat shielding applications

In this study, new composites were prepared from ethylene propylene diene rubber (EPDM) that loaded with various concentrations of short carbon fibers (SCFs) ranged from 5 up to 20 part per hundred part of rubber (phr). Aluminum trihydroxide (ATH) was added by two concentrations, namely 10 and 30 phr to EPDM/SCFs composites to enhance its heat shielding. Foaming agent, azodicarbonamide (ADC) was added to increase ablation resistance. Composites were prepared on open rubber roll mills, and then the rubber composites were gamma ray irradiated at different doses of 25, 50, 75, 100 and 150 kGy. Fiber incorporation into rubber matrix has been proven as a key factor in enhancing tensile strength and flame retardant properties of fabricated composites. The prepared composites were characterized by using various analytical methods counting physico-mechanical properties, thermal gravimetric analysis (TGA), Ablation test (oxy acetylene test) and propagation flame test. The utmost mechanical performance was reported for the incorporated 5 phr of carbon fiber into EPDM at 100 kGy. Also, the flame retardancy and ablation properties for composites were enhanced by increasing addition of carbon fibers and ATH in presence of ADC.

Boron nitride and hyperbranched polyamide assembled recyclable polyisoprene vitrimer with robust mechanical properties, high thermal conductivity and remoldability

Rubber has huge potential applications for thermal management due to its outstanding softness and elasticity, however, its low thermal conductivity limits its applications, and the vulcanized rubber also has the problem of being unrecoverable. Therefore, the development of recyclable rubber-based material with good mechanical properties, high thermal conductivity remains a challenge. Herein, the dynamic β-hydroxyl ester bonds were introduced into the composites of the epoxidized boron nitride (EBN) and the epoxidized polyisoprene (EPI) matrix via carboxyl-terminated hyperbranched polyamide (HBPA), forming dynamic covalently cross-linking rubber-based vitrimers. The covalent-bonds-mediated interface reduces the phonon scattering and enables the material to have a relatively high thermal conductivity of 0.51 W/mK under a loading of 50 phr (parts per one hundred parts of rubber) of EBN. In addition, the introduction of exchangeable bonds brings the materials the capability to change the network topology at high temperatures, exhibiting excellent recyclability and remoldability.

Ablation behavior of elastomeric insulator based on nitrile rubber containing silica or silica-clay aerogels

Nitrile-based nanocomposite heat insulators are very attractive materials, due to their higher deformation bearing in special applications such as high temperature and turbulent media, compared to their non-elastomeric counterparts. Ablation behavior of nitrile rubber-based insulators containing silica and silica-clay aerogels was investigated in comparison with those containing fumed silica. An oxyacetylene flame test under a standard condition with a heat flux of 2500 kW m−2 for 15 s was used for observation of ablation behavior of the samples. The results showed that the incorporation of 15 phr (part per hundred parts of rubber) silica aerogel into the compound decreased the mass of insulator and its linear ablation rate by 15% and 29%, respectively. The incorporation of 5 wt% organoclay in silica aerogel successfully reduced the linear ablation rate to nearly 41%. The results indicated that the insulation index number (I80) of the insulators increased about 29% and 20%, at this loading levels of silica and silica-clay aerogels, respectively. Therefore, silica aerogel played more effective role in reduction of the back-face temperature of insulators. Modeling of these ablative nanocomposites enables us to determine the exact thickness required for the insulator and the temperature distribution across it at pre-determined thermal conditions. The experimental results confirmed modeling results of the back-face temperature of the insulators.

Nanohydroxyapatite embedded blends of ethylene‐co‐vinyl acetate and millable polyurethane as piezoelectric materials: dielectric, viscoelastic and mechanical features

AbstractWe report the piezoelectric, dielectric and dynamic mechanical features of nanohydroxyapatite (nHA) embedded ethylene‐co‐vinyl acetate (EVA)/millable polyurethane (MPU) elastomer blends. The EVA/MPU/nHA systems were prepared by two‐roll milling followed by compression moulding. The piezoelectric features were probed by dynamic contact electrostatic force microscopy (EFM).The neat EVA/MPU blend was not found to exhibit ferroelectric properties. However, upon incorporation of nHA, butterfly loops of EFM amplitude signals as well as complementary hysteresis curves were obtained, confirming the introduction of ferro‐piezoelectric properties. The ferro‐piezoelectric features were found to be improved with an increase in nHA loading which recorded highest signals for 8 parts per hundred parts of rubber (phr) loaded composites. The fabricated devices generated a peak voltage of 4.02 V and 4.89 V respectively with 6 phr and 8 phr nHA loaded composites. Electrical properties such as dielectric constant, volume resistivity and loss factor as well as dynamic mechanical properties were examined. The viscoelastic features of the systems support the reinforcing feature with filler loading. TEM analysis of the composites indicated a uniform distribution of filler particles in the blend matrix, complementing the observed ferro‐piezoelectric, dielectric and dynamic mechanical properties. The simultaneous modulation of piezoelectric and viscoelastic properties is a preferred feature for fast‐responsive dielectric elastomers for their applications in various piezoelectric devices. © 2020 Society of Chemical Industry

EXPLORING THE SUITABILITY OF SOL-GEL–SYNTHESIZED NANO ZnO AS A CURE ACTIVATOR IN CARBON BLACK– AND SILICA-FILLED NR COMPOSITES

ABSTRACT Sol-gel–synthesized nano zinc oxide (ZnO) is introduced as a cure activator in carbon black (CB)– and silica-filled natural rubber (NR) composites. The performance of sol-gel–synthesized nano ZnO was systematically compared with conventional ZnO for various filled NR composites in terms of cure, mechanical, aging, and thermal properties. At a filler loading level of 40 parts per hundred parts of rubber (phr), only 1 phr nano ZnO provided a better cure rate index and tensile strength as compared with 5 phr conventional ZnO in CB-filled NR composites. On the other hand, at a 40 phr filler loading level, the cure and mechanical properties of the 1 phr nano ZnO cured NR/silica composite were comparable with the properties of the 5 phr conventional ZnO cured NR/silica composite. At the same filler loading level, both 1 phr nano ZnO and 5 phr conventional ZnO had a similar effect on the thermal stability of NR/CB and NR/silica composites. As a whole, 1 phr sol-gel–based nano ZnO could be used as an efficient cure activator instead of 5 phr conventional ZnO in CB- and silica-filled NR composites with successive reduction of ZnO level.

HAZOP Methodology Based on the Health, Safety, and Environment Engineering.

In existing risk analysis techniques like the hazard and operability study (HAZOP) and the safety integrity level (SIL), design for operator safety is not considered. The health, safety, and environment (HSE) engineering depicts a detailed design directly related to the operator safety. However, the human risk had not been comprehensively analyzed. This paper proposes HSE-HAZOP as a technique for examining the systematic and efficient application of HSE engineering by exploiting the HAZOP systematic risk analysis technique and a quantitative risk derivation method, which is an advantage of the SIL. The analysis consists of four steps: the HSE-HAZOP preparation phase, risk analysis phase, risk assessment phase, and risk reduction phase. One part of a solution styrene butadiene rubber (SSBR) plant was used for a case study. In this case study, the items that handle with heptanoic acid were the study scope. After the risk assessment, we introduced the HSE engineering technique that should be applied for the risk reduction. Since there is no existing risk analysis method for HSE engineering, this proposed HSE-HAZOP is meaningful because it suggests systematic analysis method of the operator safety.

Effect of Carbon Black Nanofiller on Adhesion Properties of SBS Rubber Surfaces Treated by Low-Pressure Plasma.

Studies on the surface modification of commercial styrene-butadiene-styrene (SBS) rubber with different carbon black (CB) nanofiller content (10–80 parts per hundred parts of rubber (phr)) performed by low-pressure oxygen plasma are presented in this paper. The adhesion properties of the rubber were determined by the peel test for adhesive-bonded joints prepared with a water-based polyurethane (PU) adhesive. The chemical structure and morphology of the SBS rubber surface before and after plasma treatment were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The peel tests showed that the plasma treatment significantly improved the strength of adhesive-bonded joints in the entire range of CB tested, revealing a clear maximum for approximately 50 phr of CB. It was also found that as a result of plasma treatment, functional groups that are responsible for the reactions with the PU adhesive, such as C−OH and C=O, were formed, and their concentration, similar to the peel strength, showed maximum values for approximately 50 phr CB. The occurrence of these maxima was explained using the bound rubber model.

ELASTOMERIC NANOPARTICLES: EFFECTIVE ADDITIVE FOR HIGH PERFORMANCE RUBBER NANOCOMPOSITES

ABSTRACT The “magic triangle” is the most important challenge to rubber composites for the automobile industry. According to the magic triangle, it is difficult to improve the rolling resistance (energy saving), wet skid resistance (safety), and wear (life) of a tire simultaneously. However, ∼5% decrease of rolling resistance, >20% increase of wet skid resistance, and 15% decrease of wear were achieved after adding a small amount of elastomeric nanoparticle (ENP). The effect of ENP on the performances of rubber composites was expounded by characterization of the dispersion of filler and the relationship between filler and rubber. The main difference between ENPs and other nanoparticles was that ENPs acted as not only a part of filler but also as a part of rubber in rubber composites.