Properties Of Rubber Research Articles

Development of sansevieria trifasciata/natural rubber composites for a soft body armor application

Body armor is an indispensable material in the military and defense. The development of body armor nowadays has shifted to lower-cost material with comparable ballistic properties. This research studied the potential of sansevieria trifasciata (ST) fiber as a reinforcement in soft body armor composite. The ST fiber was treated with various NaOH concentrations to achieve the highest tensile strength. The result showed that the highest ST fiber strength was achieved at 1.2GPa by treating the fiber with 1 wt% NaOH solution. The rebound resilience properties of the natural rubber (NR) matrix were optimized by varying the accelerator and carbon black content and were tested according to ISO 4662. The optimum energy absorption of the NR matrix was obtained using 0.4 part per hundred rubber (phr) accelerator and 30 phr carbon black. The ballistic performance of ST/NR composites was evaluated through a simulation using LS-DYNA software. The ballistic simulation revealed that the minimum thickness of ST/NR composite was 15mm to stop a bullet with a velocity of 436m/s. The results of this study indicated that ST/NR green composite was a promising candidate for a soft body armor application.

무수 말레이산 함량에 따른 말레인산 천연고무의 열적 기계적 물성 연구

무수 말레이산 함량에 따른 말레인산 천연고무의 열적 기계적 물성 연구

Dynamic properties of butadiene styrene rubbers with layered silicates

In our study, modification of SBR-1705 butadiene styrene latex using a variety of bentonite clay variants was carried out Among them were domestic sodium bentonite, domestic bentonite pretreated with surfactants (surfactants), as well as organoclays based on foreign layered silicates and also treated with surfactants at the coagulation stage with subsequent rubber release. Further, within the framework of our study, we carried out a detailed comparative study of physical and mechanical properties of rubbers produced using modified butadiene-styrene rubbers. We considered rubbers containing different variants of bentonite, including both domestic origin and imported bentonite. The dynamic properties of these rubbers, including elastic modulus and mechanical loss angle tangent, were analyzed using dynamic thermomechanical analysis (DTMA). The study found that the rubber samples containing PT clay and Cloisite 30B showed a 20% reduction in mechanical loss tangent within the operating temperature range. This indicates an improvement in the mechanical properties of the rubber under a variety of operating conditions. In addition, rubber samples containing imported layered silicates and treated with surfactants exhibited increased strength both before and after thermo-oxidative aging at 150°C. These results emphasize the importance of silicate and surfactant composition selection in developing rubbers with improved mechanical properties and durability. The findings of this study have important implications for industry and academia, emphasizing the role of proper bentonite selection and processing in creating rubbers with optimal performance for a variety of applications

Synthesis of sonochemical chloroacetated natural rubber and its potential use in passenger car tire tread

This article describes the preparation of chloroacetated natural rubber (CNR) through the epoxidation of natural rubber (NR) latex with performic acid, followed by the reaction with chloroacetic acid. Ultrasound waves were utilized to accelerate the epoxidation reaction. The CNR samples obtained at various epoxidation durations were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. Results showed that the chloroacetate content in CNR increased with increasing epoxidation time, i.e., the chloroacetate contents were 17.4, 18.5, and 19.7% at epoxidation times of 30, 45, and 60 min, respectively. The prepared CNR samples were then employed to replace NR in silica-filled tire tread compounds based on a 70/30 solution styrene butadiene rubber (SSBR)/NR blend. It was found that, compared with NR, CNR provided significantly higher rubber-silica interaction, leading to improved mechanical and dynamic properties. Such replacement not only reduced heat build-up and rolling resistance, but also increased the wet grip index, which is highly beneficial for the production of high-performance passenger car tires. It could be observed that the improvements in rubber properties and tread performance were more obvious when the chloroacetate content of CNR was increased, probably due to the enhanced rubber-filler interaction, as demonstrated by the increased bound rubber content.

Underwater sound-absorbing performance of composite structure under hydrostatic pressure by considering constitutive models

Underwater vessels face significant challenges as the high hydrostatic pressure of deep water affects their stealth performance. Linear models may not accurately depict the deformation of structures under hydrostatic pressure due to its non-linear properties of rubber and therefore, influence the results. This study utilized uniaxial tension and compression test data of styrene-butadiene rubber to fit four constitutive models and the optimal was selected to calculate the sound-absorbing performance under hydrostatic pressures,. Results showed that the Yeoh model fitted by uniaxial compression with r2 of 0.9928. Viscous losing, waveform conversion and locally resonance are main sound-absorbing mechanisms. The maximum sound-absorbing coefficient of structure at 0 MPa is 0.8914 at 7.6 kHz and the sound-absorbing performance mostly decreases with increasing hydrostatic pressure, Maximum reduction of 32 % was achieved at 3.2 kHz. Experiments verified the accuracy of simulation results, and the mean relative errors between the simulated results and the experimental results are 15.28 % (0 MPa), 16.91(0.5 MPa) %, 16.67 % (1 MPa) and 16.38 % (2 MPa), respectively. These findings can provide guidance for development of underwater sound-absorbing structures in hydrostatic pressure conditions.

Enhancement of hydrophobic properties of HTV silicone rubber by CF4 plasma treatment

In this paper, a superhydrophobic surface of silicone rubber was fabricated by plasma treatment method. Modification of the surface chemistry under CF4 atmosphere at different times (3, 5, and 7 min) and powers (50, 75, and 100 W) of plasma process has been investigated. A superhydrophobic surface with contact angle of 151.3° was obtained for plasma treated sample at 100 W for 7 min. X-ray photoelectron spectroscopy (XPS) results indicated that the surface fluorination of silicone rubber increased as the time and power of plasma exposure increased. Investigation of the F 1s and Si 2p spectra approved the formation of F-C and F-Si bands. Also, the roughness of the surface increased from about 42 nm for untreated to 55 nm for treated sample (7 min at 100 W) due to the emergence of the ceramic fillers in degraded silicone rubber matrix after plasma treatment. Both of the surface fluorination and roughness increment are the reasons of superhydrophobicity properties. Examination of the hydrophobic recovery by surface contamination method indicated that a contact angle of 101° was recovered after 9 days.

Influence of oligomeric resins on natural rubber-carbon black-silica composites for tire tread application

The investigation aims to understand the impact of different resins on properties of natural rubber (NR) based tire tread composites, providing valuable insights for the optimization of tire performance. In current research six different types of resins, namely rosin modified dicyclopentadiene(DCPD), gum rosin, C5 aliphatic resin, alpha methyl styrene (AMS) resin, koresin and terpene phenol resin, were selected for assessing structural influence of resins on cure characteristics, reinforcement, abrasion resistance, cut-tear resistance, heat-build-up, viscoelastic properties of carbon black-silica loaded NR composites. During mixing of rubber composites, condensation reaction between hydroxyl groups of silica with phenolic groups of koresin and terpene phenol resin, leading to elimination of water molecules was confirmed by Fourier transform infrared spectroscopy. The addition of resins led to a reduction in crosslink density, maximum torque and delta torque. The compounds with gum rosin and rosin modified DCPD showed lower crosslink densities translating into lower tensile strength, lower stress at 100%, 200%, 300% strain, and higher elongation at break among the resins. Rosin modified DCPD based composite exhibited the highest cut growth resistance and tear strength. Rolling resistance indicator (tanδ@70 °C) of resin-based composites followed the order: gum rosin > rosin modified DCPD > koresin > C5 resin > terpene phenol resin > AMS resin. The snow traction (tanδ@-15 °C), the order was: AMS = C5 > gum rosin > terpene phenol = koresin > rosin modified DCPD. The dynamic stiffness (É) of the gum rosin-based compound was significantly increased at low strain (0.1%) and low temperatures (-80–20 °C) compared to other resins. Furthermore, atomic force microscopy was employed to analyze surface topography and roughness of the resin-based NR composites, providing valuable insights into interfacial characteristics.

Effect of zinc oxide/layered double hydroxide on friction properties of silicone rubber at low temperature

Effect of zinc oxide/layered double hydroxide on friction properties of silicone rubber at low temperature

A Molecular Dynamics Simulation Study on Enhancement of Mechanical and Tribological Properties of Nitrile-Butadiene Rubber with Varied Contents of Acrylonitrile.

The molecular models of nitrile-butadiene rubber (NBR) with varied contents of acrylonitrile (ACN) were developed and investigated to provide an understanding of the enhancement mechanisms of ACN. The investigation was conducted using molecular dynamics (MD) simulations to calculate and predict the mechanical and tribological properties of NBR through the constant strain method and the shearing model. The MD simulation results showed that the mechanical properties of NBR showed an increasing trend until the content of ACN reached 40%. The mechanism to enhance the strength of the rubber by ACN was investigated and analyzed by assessing the binding energy, radius of gyration, mean square displacement, and free volume. The abrasion rate (AR) of NBR was calculated using Fe-NBR-Fe models during the friction processes. The wear results of atomistic simulations indicated that the NBR with 40% ACN content had the best tribological properties due to the synergy among appropriate polarity, rigidity, and chain length of the NBR molecules. In addition, the random forest regression model of predicted AR, based on the dataset of feature parameters extracted by the MD models, was developed to obtain the variable importance for identifying the highly correlated parameters of AR. The torsion-bend-bend energy was obtained and used to successfully predict the AR trend on the new NBR models with other acrylonitrile contents.

Using a facile method to predict properties of recycled waste nitrile rubber (NBR) through devulcanization

To prepare a reliable method for predicting the properties of devulcanized rubbers a nitrile rubber (NBR) compound was prepared and masticated before vulcanization for 0, 30 and 60 min under mechanical stress to prepare NBRs with different molecular weights. The masticated samples were vulcanized at different accelerator contents to prepare damples with different crosslink densities. The physical/mechanical/thermal properties (i.e. crosslink density, tensile strength, modulus, modulus at 100 and 300% elongation, elongation at break, hardness, curing behavior and molecular weight) of the samples were experimentally evaluated. In the next step, the prepared samples were assumed as devulcanized NBRs that underwent chains scission (masticated samples) or crosslinks breakage (vulcanized at different accelerator contents). On this basis, hypothetical devulcanization routes were considered between each sample that underwent chains scission or crosslinks breakage. Based on the results, numerical relationships between the number of chains scission or crosslinks breakage and decrease in the properties were obtained. Finally, the numerical reationships were used to calculate the properties of the samples that underwent both of chains scission and crosslinks breakage. It was found that the calculated contents of hardness, modulus at 100% and molecular weight (MZ) using the prepared method were very close to the evaluated ones.

Research on dynamic mechanical properties of polypropylene fiber-modified rubber foamed concrete

To investigate the dynamic properties of polypropylene fiber-modified rubber foamed concrete (PPR-FC), foamed concrete (FC), and foamed concrete with recycled rubber granules (R-FC) specimens with wet densities of 700 kg/m3, 800 kg/m3, and 900 kg/m3 were prepared for evaluation of dynamic performance (including dynamic elastic modulus and impact resistance) and unconfined compressive strength. The test results showed that PPR-FC was density-dependent. The polypropylene fiber (PP fiber) was helpful in improving the toughness of the material. In particular, the improvement of the unconfined compressive strength and impact performance based on the destructive test was more obvious, with a maximum increase of 18.15% and 78.34%, respectively. The impact performance was determined by the maximum number of impacts that can be withstood. The rubber granules increased the specimen’s ductility, which is positive to impact resistance with the maximum improvement of 470.41%, meanwhile increasing the wet density that can effectively remedy the decrease of the unconfined compressive strength and dynamic elastic modulus. Moreover, the dynamic elastic modulus was positively related to the frequency as a whole due to the strain rate effect. Then, the microscope test showed that fiber can connect the bubble structure, making the bubble structure more stable, but also increasing the number of irregular and large-diameter bubbles. The rubber granules changed the shape of bubbles around the granules, and increased the number of large-size bubbles, while decreasing the overall number of bubbles. Finally, according to the test results, the prediction formula of dynamic elastic modulus and impact resistance based on multiple factors was established. As a result, this paper can provide a reference for the application of PPR-FC in engineering practice.

Mechanical Properties, Radiation Resistance Performances, and Mechanism Insights of Nitrile Butadiene Rubber Irradiated with High-Dose Gamma Rays.

The radiation effect of materials is very important and directly related to the safety and reliability of nuclear reactors. Polymer materials, one of the indispensable materials in nuclear power equipment, must withstand the ordeal of high-energy ionizing rays. In this work, through screening different γ-ray dose irradiation conditions, we systematically and comprehensively study the changes in the structure and properties of nitrile butadiene rubber (NBR) before and after γ-ray static irradiation at a high dose rate, and master the rule and mechanism of the γ-ray static irradiation effect of these polymer materials. The mapping relationship between the macroscopic properties, microstructure, and irradiation dose of NBR is accurately characterized. With an increase in total irradiation dose, the C=C double bond reaction occurs, and the C≡N bond, C=C, and C=O participate in the hyper crosslinking reaction. The glass transition temperature (Tg) increases with the cumulative irradiation amount. With the increased total irradiation amount, the degree of rubber cross-linking increases, causing an increased crystallinity and decomposition temperature. A growing amount of gamma irradiation causes the mechanical properties of the rubber to degrade simultaneously, increasing the shore hardness while decreasing the tensile strength and ultimate elongation at break. When the cumulative amount reaches 1 MGy, the ultimate elongation at break decreases significantly. A cumulative dose of radiation resistance of 4 MGy can be achieved by the samples. This work can provide theoretical and experimental support for the long-term stability of nitrile butadiene rubber and its derivatives in nuclear radiation fields and space radiation conditions.

Improvement in strain‐induced crystallization and physicochemical property of natural rubber by protease treatment

AbstractNatural rubber (NR) distinguishes itself from a synthetic one in that it contains non‐rubber components and is subject to strain‐induced crystallization (SIC). Non‐rubber components may have a great influence on the physicochemical properties and SIC behavior of NR. However, the underlying mechanisms remain poorly understood. This work uses protease to treat the non‐rubber components so as to control their content. The mechanical properties, dynamic properties, and crystallization kinetics of the resulting NR are compared. The protease treatment shortens the solidification time of latex. Thus, a higher phospholipid content is retained. A higher protease content yields better mechanical and dynamic properties. Protease‐treated NR shows a SIC behavior at lower strain and a higher crystallinity at the same strain. This indicates that phospholipids have a greater impact on the properties than proteins, namely they better speed up vulcanization and SIC.

Characterization and Application in Natural Rubber of Leucaena Leaf and Its Extracted Products.

Leucaena is a fast-growing tree in the legume family. Its leaf contains a significant amount of protein and is thus widely used as fodder for cattle. To broaden its application in the rubber field, the effects of Leucaena leaf powder and its extracted products on the cure characteristics and mechanical properties of natural rubber were investigated. The extraction of Leucaena leaf was carried out by using a proteolytic enzyme at 60 °C. The digested protein was separated from the residue by centrifugation. Both digested protein and residue were then dried and ground into powder, namely digested protein powder and residual powder, respectively, before being characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis, X-ray diffraction, particle size determination, and protein analysis. After being added to natural rubber at 3 parts per hundred rubber, they significantly reduced both the scorch time and the optimum cure time of the rubber compounds, probably due to the presence of nitrogen-containing substances, without a significant sacrifice of the mechanical properties. For instance, the optimum cure time decreased by approximately 25.5, 35.4, and 54.9% for Leucaena leaf powder, residual powder, and digested protein powder, respectively. Thus, they can be used as green and sustainable fillers with a cure-activation effect in rubber compounding.

A comprehensive review of the recent developments in thermoplastics and rubber blends‐based composites and nanocomposites

AbstractVarious blends and composites have been prepared during the past decade to address limitations, including the poor mechanical properties of polymers, or to balance out the high cost of synthetic polymers. Rubber‐based thermoplastic blends and composites are being developed to attain improved performance and balanced qualities for usage in a variety of industries, including automotive, packaging, home products, space technology, and biomedical. Thermoplastics can be produced via standard manufacturing procedures and have outstanding qualities like low density, good chemical resistance, and heat resistance. However, rubbers are being used because of their elastic attributes, including their resilience, impact resistance, and good tear strength. These two materials work well together when blended or combined. In this article, an effort was made to narrow the gap between rubbers and thermoplastics. The mechanical, rheological, and morphological properties of the rubber/thermoplastic blends and composites/nanocomposites containing various types of conventional fillers and nanofillers were discussed comprehensively. Blends of these materials can provide too easier melt processing as well as financial benefits. The flexible nature and damping properties of rubber and better thermal stability and thermoplastic processability contributed to the development of high‐performance rubber/thermoplastic composites with better ductility, impact strength, and stiffness. Rubber reduced the high brittleness of thermoplastics because of its resilience and damping properties. In contrast, the poor processability and weak chemical resistance of rubbers were overcome via better processability and higher stiffness of thermoplastics. Rubber‐based thermoplastic composites and nanocomposites have been reported to offer greater flexibility, better processing, high impact strength, and chemical resistance.Highlights The properties of rubber/thermoplastic blends were discussed in this article. More recent advancements in rubber/thermoplastic blends were evaluated. Morphological properties depend on the rubber/thermoplastic blend ratio. The addition of reinforcements affects the rheological properties. Dispersion of additives and blend ratio influence the mechanical properties.

Development of exfoliated mica waste/natural rubber composites by latex stage mixing

ABSTRACT Raw mica powder may not show better physico-mechanical properties in rubber owing to its large particle sizes and low degree of surface activeness. Here, mica waste; a green filler was modified by partially exfoliating before incorporating it into natural rubber (NR). The latex stage mixing was conducted to incorporate different loadings of exfoliated mica waste (eWM). The incorporation of eWM had no significant effect on cure and scorch time. The reduction of viscosities indicated better processability of the compounds. The overall improvement of moduli, tensile, abrasion resistance, and cross-link densities supported by SEM and TGA data suggested improved rubber–filler interactions.

Stress-strain state of a composite tractive element with a broken structure due to elastomer shell rheology

Purpose. Establishing a dependency of change in a stress-strain state for a rubber-cable tractive element with broken structure due to rheology of a rubber shell. Methods. Analytical solution of a model of a rubber-cable tractive element with a broken structure due to rheology of a rubber shell. Results. An algorithm for determining a stress-strain state of a rubber-cable tractive element with a broken structure due to rheology of a rubber shell is developed. The suggested algorithm involves splitting the rope into two parts, which allows considering the influence of a dependency of shear modulus on deformations in a form of a broken line constructed of two segments. Splitting the rope in the area of integrity breakage into three or more parts allows considering a more complex dependency of shear modulus on shear deformations. A mechanism of changing a stress-strain state of a rubber-cable rope due to rheology of a rubber shell is established. The local influence of changes in properties of elastic material interacting with a damaged cable on a stress-strain state of a rubber-cable tractive element with a broken structure is analyzed. Scientific novelty. A mechanism of influence of a shear modulus of rubber shell material in the rubber-cable rope (belt) with a cable integrity breakage on stress-strain state of composite tractive element is established to be time-varying and nonlinearly dependent on deformations. Practical significance. Consideration of shell rubber rheology makes it possible to predict a rope stress state considering a non-linear law of changes in properties of rubber during its use and to increase safety and operational reliability of rubber-cable tractive elements. A local change in mechanical parameters does not increase the danger of using a rope with continuity breakages of cables. An increase in lengths of redistribution of forces and displacements requires an increase in length of steps in butt-joint connections.

Influence of filler concentration and type on rheological and mechanical properties of liquid isoprene rubber for high-strength parts via material extrusion

This study investigates the rheological behavior and material extrusion performance of liquid isoprene rubber (LIR) compounds filled with carbon black (CB), silica (Si), and recycled crumb rubber (CR) fillers for potential additive manufacturing applications. The rheological properties of the LIR mixtures were characterized using flow curve analysis and temperature sweeps, identifying shear-thinning behavior and temperature-dependent viscosity ultimately reflecting the final dimensional tolerance of the prints. Vulcanization time (t90) was determined using oscillatory rheometry, and the effect of filler concentration on t90 was evaluated. Mechanical testing was conducted to assess the hardness and tensile properties. The results demonstrate the influence of filler concentration on the rheological properties, printability, and mechanical performance of the LIR compounds thus resulting in the printing of high-strength (σu > 5 MPa) isoprene rubber parts capable of being additively manufactured.

Phosphate adsorption from water and wastewater using non-devulcanised and devulcanised tyre rubber

The secondary use of tyre rubber is a potentially sustainable environmental solution. However, the sorption properties of used-tyre rubber have not yet been fully investigated. In this study, the rubber type (vulcanised or devulcanised part-worn tyre rubber) that can sorb phosphate phosphorus from aqueous solutions or wastewater more effectively is determined. The capacity of granules (0.3–1.0 mm in diameter) of non-devulcanised ground tyre rubber and uniquely chemically devulcanised rubber to adsorb phosphorus is evaluated under laboratory conditions. The results show that under the filtration of an aqueous solution or biologically treated wastewater at a flow rate of 0.75 m/h (1.2 L/h), 1 g of the devulcanised rubber medium accumulates 5.16 mg of phosphorus, which is five times more than that accumulated by the non-devulcanised rubber medium. The surface structure of the non-devulcanised rubber medium is more suitable for the sorption of devulcanised rubber granules. The sorption capacity and effectiveness of non-devulcanised rubber for phosphorus removal are more favourable compared with those of the tested natural and waste-prepared sorbents. Further research into this material as a medium for filter layers and for accumulating drainage should be conducted. The findings of this study are important for addressing issues associated with the secondary use of tyre rubber.

Hybrid viscoelastic damper using natural rubber compound, waste of rubber tire crumb with various compacted sands (iron sand, natural sand, and silica sand) to increase damping property for non-engineered buildings

To reduce lateral deformation due to earthquake shake has been carried out by strengthening techniques. Such techniques require additional structural elements such as bracing or shear wall, if not applying additional new materials on beams or columns such as CFRP. This study focuses on the formation of the hybrid rubber dampers from materials such as natural rubber compound (NRC), waste of rubber tire crumb (WRTC), compacted natural sand, iron sand, and silica sand. The main goal of this research is to investigate the dynamic properties of hybrid materials of compacted various sands encapsuled with the NRC and WRTC compound. Nonetheless, the mechanical properties of rubber, such as tensile strength and modulus of elasticity, were also tested. In this research, the specimens were in the form of a square block of 100 x 100 mm2 base and 25 mm thickness and consisted of two types of specimens for reference i.e., fully natural rubber compound (NRC) and blended NRC with 25% by volume of the WRTC, namely MRTC. Furthermore, other three types of hybrid viscoelastic dampers (HVD) were also provided i.e., 1) compacted natural sand, 2) compacted iron sand, and 3) compacted silica sand, which were all wrapped with WRTC in a proportion of 3:4 by volume. The results show that the addition of the MRTC reduces the tensile strength and elastic modulus in comparison to the NRC but increases the damping properties. Moreover, the elaboration of compacted natural sand, iron sand, and silica sand in the HVD also shows an increase in the damping properties up to 200%.