Types Of Rubber Research Articles

Toughness Enhancement of PLA-Based Filaments for Material Extrusion 3D Printing

Poly(lactic acid) (PLA) is one of the most popular biodegradable thermoplastics in the market of 3D printing filaments used in the material extrusion (ME) technique. This is because it can be printed easily at low temperatures. However, its inherent brittleness limits its use in many applications. In this work, the toughness of PLA filament was improved by blending with various types of rubbers including natural rubber (NR), acrylic core–shell rubber (CSR), and thermoplastic polyurethane (TPU) in the amount of 15% by weight. PLA/TPU filament was found to have the smoothest surface with the best shape and dimension stability, while PLA/NR filament rendered the highest tensile toughness. In term of the effect of printing temperature, the highest printing temperature in this study (210°C) provided the highest smoothness with the best shape stability and dimension accuracy. Interestingly, the tensile toughness and elongation at break of 3D printed specimens were found to be higher than those of compression-molded specimens for all filament types. This could be explained by the ability of the 3D printing technique to produce specimens that aligned in the printing direction in a fiber-like pattern.

Estimation of non-linear mechanical properties of rubber using Split Hopkinson pressure bar

The material non-linearity is a very important phenomenon in the behavior of the materials subjected to high strain rate loading. Rubber is a material which has high damping properties due to which it is more vulnerable in applications that involve absorption of vibration and shock; generally, these damping materials are subjected to high strain rate loading while absorbing the load. In the present work, various types of rubbers are subjected to very high-velocity impact due to which a very high strain rate loading is applied on the rubber specimens through the usage of Split Hopkinson Pressure Bar apparatus. The behavior of the rubber specimens at this high-velocity impact loading is studied through the variation of stress, strains, and strain rate with time. A comparison is drawn between various rubbers and the best rubber for the impact applied, is evolved and the same is presented in the work.

Some problem questions in studying the properties of dynamically vulcanized polymer systems based on ethylene/1-hexene copolymer and nitrile butadiene rubber

The article presents the results of a study of the influence of the type and concentration of nitrile butadiene rubber on the main physical and mechanical properties of polymer compositions based on compatibilized ethylene/1-hexene copolymer (EHC*). SKN-18, SKN-26, and SKN-40 were used as nitrile butadiene rubber. The compatibilizer – polyethylene-graft-methacrylic acid was used to improve the compatibility of the mixed components of the mixture. At the first stage, the task of the study was to investigate the effect of the concentration of the considered nitrile rubbers on such properties of the compositions as yield strength, tensile strength, elongation at break, flexural strength, melt flow rate and heat resistance. It was found that, regardless of the type of used nitrile butadiene rubber, with an increase in its content in the composition of the ethylene/1-hexene copolymer, a regular decrease in strength parameters, heat resistance, and melt fluidity is observed. It is shown that with the loading of 30 wt% SKN-18 or 40 wt% SKN-26 and SKN-40 into the composition of the ethylene/1-hexene copolymer phase inversion occurs in the composite materials, according to which the dispersed phase becomes a dispersed medium. The thermomechanical properties of the considered samples were studied. It was found that in those samples in which phase inversion occurred, a region of a highly elastic plateau is formed, which increases with an increase in the content of the rubber component. This area indicates the formation of elastomer with rubber properties. The regularities of crystallization of the compositions depending on the content of the amorphous component were studied by the method of stepwise dilatometry. The mechanism of crystal formation was studied depending on the content of the amorphous component. The influence of the crosslinking agent concentration – dicumyl peroxide on the main properties of dynamically vulcanized elastomers has been studied.

Introduction of Consumable Primers in Consumable Tires of Petrochemical Complexes in Hard Rubber Types

Introduction of Consumable Primers in Consumable Tires of Petrochemical Complexes in Hard Rubber Types

Introduction of Consumable Primers in Consumable Tires of Petrochemical Complexes in Hard Rubber Types

Introduction of Consumable Primers in Consumable Tires of Petrochemical Complexes in Hard Rubber Types

Control of Tire Wear Particulate Matter through Tire Tread Prescription.

This study aims to analyze tire wear particulate matter (TWP) from tread rubber with different formulations and to compare the concentration of TWP with different wear devices. The TWP generated during the abrasion of truck and bus radial (TBR) tires were examined, and the effect of using different types of rubber and carbon black (CB) were investigated. When natural rubber (NR) was solely used as the tire tread rubber material, there was a higher concentration of 5-10 µm TWP. However, when the tread formulation consisted of NR mixed with butadiene rubber, the TWP concentration decreased. Changing the type of CB also reduced the amount of TWP in the 2.5 µm size range. The TWP concentration in the specimens increased with increasing speed and vertical load. The TWP generated during the abrasion tests using wear testers and tire simulators exhibited similar trends. These findings suggest that modifying tire tread formulations can effectively control the distribution and amount of TWP generation.

Carbon Rovings as Strain Sensor in TRC Structures: Effect of Roving Cross-Sectional Shape and Coating Material on the Electrical Response under Bending Stress.

This study investigated the ability of electrically conductive carbon rovings to detect cracks in textile-reinforced concrete (TRC) structures. The key innovation lies in the integration of carbon rovings into the reinforcing textile, which not only contributes to the mechanical properties of the concrete structure but also eliminates the need for an additional sensory system, such as strain gauges, to monitor the structural health. Carbon rovings are integrated into a grid-like textile reinforcement that differs in binding type and dispersion concentration of the styrene butadiene rubber (SBR) coating. Ninety final samples were subjected to a four-point bending test in which the electrical changes of the carbon rovings were measured simultaneously to capture the strain. The mechanical results show that the SBR50-coated TRC samples with circular and elliptical cross-sectional shape achieved, with 1.55 kN, the highest bending tensile strength, which is also captured with a value of 0.65 Ω by the electrical impedance monitoring. The elongation and fracture of the rovings have a significant effect on the impedance mainly due to electrical resistance change. A correlation was found between the impedance change, binding type and coating. This suggests that the elongation and fracture mechanisms are affected by the number of outer and inner filaments, as well as the coating.

Ground Tire Rubber Particles as Substitute for Calcium Carbonate in an EPDM Sealing Compound.

Ground tire rubber (GTR) is a product obtained by grinding worn tire treads before retreading them or via the cryogenic or ambient temperature milling of end-of-life tires (ELTs). The aim of this study is to evaluate if calcium carbonate can be substituted by GTR and, if so, to what extent. Different types of ground tire rubber are incorporated in an EPDM (ethylene-propylene-diene-rubber) model compound as partial or complete substitutes of calcium carbonate. The raw compounds and the vulcanizates are characterized to identify the limits. In general, it is apparent that increasing amounts of GTR and larger particles degrade the mechanical properties. The GTR also influences the vulcanization kinetics by reducing the scorch time up to 50% and vulcanization time up to nearly 80%. This is significant for production processes. The compounds with one-third substitution with the smaller-particle-size GTR show mostly similar or even better properties than the reference.

Adsorption of aqueous Pb(II) using non-devulcanized and devulcanized tyre rubber powder: a comparative study.

This study aimed to compare the adsorption of Pb(II) ions from an aqueous solution using non-devulcanized (NTR) and devulcanized tyre rubber (DTR) powder. Both types of rubber particles were prepared from used truck tyres, with DTR processed through mechano-chemical devulcanization. The adsorption experiments were conducted using 100-200µm particles, with adsorbent doses ranging from 5 to 15g/L. Effects of adsorbent dose, initial metal concentration and contact time were investigated. Characterization of both adsorbents was done using SEM-EDS, FTIR, and XRD analysis. Different adsorption isotherm and kinetic models were used to analyse the adsorption mechanisms. The results of the study showed that DTR was significantly more efficient at adsorbing Pb(II) compared to NTR. The maximum adsorption capacities estimated from the Langmuir equation were 75.1mg/g and 6.61mg/g for DTR and NTR, respectively. Among the kinetic models tested, pseudo 2nd order kinetic model was found to be the most suitable for tyre rubber adsorbents. The optimal dose and contact time were found to be 5g/L and 120min, respectively, for both adsorbents. The superior performance of DTR in Pb(II) adsorption was attributed to the change in the surface morphology of the rubber during the devulcanization process, resulting in increased surface roughness. The adsorption of Pb(II) was accompanied by the leaching of Zn from both types of rubber, suggesting that an ion exchange mechanism might be involved in the adsorption process. In conclusion, devulcanization appears to be a viable method for improving the adsorption properties of tyre rubber.

Phase aberration correction for ultrasound imaging guided extracorporeal shock wave therapy (ESWT): Feasibility study

Image guidance of extracorporeal shock wave therapy (ESWT) is important to enhance its efficacy while lowering pain in patients. Real-time ultrasound imaging is an appropriate modality for image guidance, but its image quality substantially reduces due to severe phase aberration from the different speed of sound between soft tissues and a gel pad, which is utilized to control a therapeutic focal point in ESWT. This paper presents a phase aberration correction method for improving image quality in the ultrasound imaging guided ESWT. To correct an error from phase aberration, a time delay based on a two-layer model with different speeds of sound is calculated for dynamic receive beamforming. For the phantom and in vivo studies, a rubber type gel pad (i.e., 1400 m/s) with a specific thickness (3 or 5-cm) was placed on the top of soft tissue and full scanline RF data were acquired. In the phantom study, with phase aberration correction, image quality was highly increased compared to image reconstructions with a fixed speed of sound (i.e., 1540 or 1400 m/s), i.e., 1.1 vs. 2.2 and 1.3 mm in −6dB lateral resolution and 0.64 vs. 0.61 and 0.56 in contrast-to-noise ratio (CNR), respectively. From an in vivo musculoskeletal (MSK) imaging, the phase aberration correction method provided a clearly improved depiction of muscle fibers in a rectus femoris region. These results indicate that the proposed method enables effective imaging guidance of ESWT by improving image quality of ultrasound imaging in real-time.

Effect of Blowing Agents on Properties of Cellular rubber of Natural rubber / Chloroprene blends

Cellular or sponge rubber can be by expansion of fluid state by gas produced from decomposition of foaming agents [1]. It can be manufactured from various types of rubber and chemicals depending on properties required [2]. Natural rubber can give excellent mechanical properties except for thermal ageing [3]. The objectives of this work were to improve thermal ageing of NR foam by incorporating chloroprene rubber, CR, into NR and foaming NR/CR blends. In order to study the effects of the type of chemical blowing agents on the properties of cellular NR/CR rubber blends, azodicarbonamide (ADC) and oxybisbenzenesulfonyl hydrazide (OBSH) were used as blowing agents and compared. The cure characteristic, mechanical, morphological, and flammability properties of the foams were investigated. The results indicated an increasing chloroprene rubber loading caused the increase in cure time, but decreased in cure rate index. In both cases of foaming agents, the cellular rubbers were found that tensile and tear strength were decreased with CR rubber loading, but the secant modulus and hardness were increased. Compression set was decreased with CR rubber loading. It is also showed that the flammability of NR/CR foam with high CR contents (more than 80%) was better than that with low CR contents. It is also found that using OBSH as foaming agent can produce cellular rubber containing better cell density and cell size distribution than ADC.

Capacitive Extensometry for the Estimation of Meaningful Stretch-Dependent Dielectric Strength of Dielectric Elastomer

The electromechanical performance of a dielectric elastomer (DE) is greatly influenced by the dielectric strength of the elastomeric materials. The dielectric strength of an elastomer profoundly depends on the state of mechanical stretch. In this work, the stretch-dependent dielectric strength for DE is measured for all possible modes of stretches using compliant electrodes. Dielectric breakdown measurement using compliant electrodes considers voltage-induced deformation, which reflects the actual working condition energy transduction. Hence, the measured strength is for a meaningful value of a working DE. Capacitive extensometry and optical method are the two leading methods for the same. We compare the extensometry and optical methods in estimating the true value of dielectric breakdown strength of DEs at high prestretches. Furthermore, we propose a modified thickness stretch-based power law for the dielectric breakdown strength. Using the capacitive extensometry method, we verify the model on comprehensive experimental data on three types of elastomers, i.e., acrylic, silicone, and natural rubber. This work proposes a general framework for estimating the meaningful stretch-dependent dielectric strength of DEs.

In-situ and real-time nano/microplastic coatings and dynamics in water using nano-DIHM: A novel capability for the plastic life cycle research

A novel nano-digital inline holographic microscope (nano-DIHM) was used to advance in-situ and real-time nano/microplastic physicochemical research, such as particle coatings and dynamic processes in water. Nano-DIHM data provided evidence of distinct coating patterns on nano/microplastic particles by oleic acid, magnetite, and phytoplankton, representing organic, inorganic, and biological coatings widely present in the natural surroundings. A high-resolution scanning transmission electron microscopy confirmed nano-DIHM data, demonstrating its nano/microplastic research capabilities. The sedimentation of two plastic size categories was examined: (a) ∼10 to 700 µm, and (b) ∼ 1 to 5 mm. Particle size was the primary factor affecting the sedimentation for studied (a) microplastics and (b) pellets. Two types of silicone rubbers exhibited different sedimentation processes. We also demonstrated that inorganic ions in seawater and oleic acid organic coatings altered the sedimentation velocity of studied plastics by 9 – 13% and 5 – 9%, respectively. Semi-empirical probability functions were developed and incorporated into a numerical model (CaMPSim-3D) to simulate the transport of studied microplastics and pellets in the Saint John River estuary. Water dynamics was the driving force of plastic transport, yet the accumulation of plastics was selectively dependant on particle physicochemical properties such as size and density by ∼ 7%. The usage of nano-DIHM for targeted identification of nano/microplastic hotspots and aquatic plastic wastes remediation were discussed.

The tough and multi‐functional stretchable device based on silicone rubber composites

AbstractRecently, the advances in stretchable electronic devices have attracted great attention around the world. New technologies are constantly updated to obtain a stretchable device with high performance and robust durability. The stretchable device‐based rubber composites were prepared with the addition of room‐temperature‐vulcanized silicone rubber (RTV‐SR) and different types of nanofillers such as graphite nanoplatelets (GNP), molybdenum disulfide (MoS2), and their hybrid. The hybrid composites contain both nanofillers in 50:50 ratios. The mechanical performance of the stretchable device was studied and presented. For example, the compressive modulus was 1.86 MPa (virgin), and at 20 per hundred parts of rubber (phr) was 3.9 MPa (GNP), 2.3 MPa (MoS2), and 2.72 MPa (Hybrid). The mechanical stretching ability of the composites was 120% (virgin), and at 20 phr was 170% (GNP), 182% (MoS2), and 171% for (Hybrid). At end of the work, a novel stretchable device based on a piezo‐electric effect is presented which provides an output voltage of ~1.2 V and high durability of >0.1 million cycles without significant degradation. This device is based on a rubber composite with the inclusion of electro‐active and dielectric materials as described in the subsequent section of the paper.

Sustainable production of recycled rubber waste composites with various epoxy systems: A comparative study on mechanical and thermal properties

In this study, ethylene-propylene-diene monomer rubber (EPDM) and tire waste powder (TW) were selected as filling materials for toughening various epoxy matrices, lowering composite materials costs and converting these wastes into valuable resources. Two types of bisphenol-A epoxy resins (ER1 and ER1diluted), and three types of epoxy resin blend systems with ER1diluted, CTBN rubber modified (ER2), and polyurethane modified (ER3) epoxies in 1:1 wt ratio were used as matrices. The effects of the rubber ratio and type, also the epoxy matrix on the composite properties were investigated. The TW composites' mechanical and thermal properties were higher than those of the EPDM composites. The best results for resin mixtures were obtained with ER3. The most suitable filling ratio of EPDM and TW varied between 20% and 30% by weight, depending on the matrix type. TW addition increased the impact strength of the ER1diluted and ER3-ER1diluted epoxy matrices. In terms of mechanical properties, the low ambient temperature was found to be more suitable than an aqueous medium.

Study on the aging of three typical rubber materials under high- and low-temperature cyclic environment

Abstract As the key components of sealing applications, rubber seals are subject to complicated environmental conditions during the service lifetime. In this study, the aging of three typical rubber materials, ethylene–propylene–diene monomer rubber, liquid silicone rubber, and fluorine rubber, was tested under different high- and low-temperature cycle aging environments. The experimental results confirm that the reciprocating temperature cycle causes a type of fatigue failure, which could result in an increase in the rubber compression set. In addition, a novel accelerated aging test method was proposed based on the dominant damage mechanism of rubber material caused by the temperature cycle treatments. Based on this method, the long-term aging test results of rubber samples under high- and low-temperature cycle conditions can be predicted. This method could significantly shorten the aging test time and reduce the test cost.

The Characterisation of Fracture Resistance of Asphalt Mixtures Containing Rubber Modifiers and a Wax-Based Additive

Asphalt mixture modification with rubberised material frequently results in improved characteristics and extended service life in actual application. This research characterised the synergistic consequences of rubber modifiers (crumb rubber powder (CRP) and natural rubber latex (NRL)) and wax-based admixtures (Tough Fix Hyper (TFH)) on the performance of the asphalt mixture from the fracture energy and laboratory fracture resistance perspectives. Semicircular bending (SCB) and indirect tensile strength (ITS) tests were conducted to assess the fracture properties of the asphalt mixture samples. To prepare asphalt mixture samples, the wet method was utilised. Higher CRP levels resulted in greater strength and a longer time to attain peak force for both control and mixtures containing wax admixture, as determined by SCB. The interaction between the higher CRP or NRL content and the TFH additive enhanced the fracture resistance, indicating that the components are highly compatible. The 10L + TFH additive produced the highest fraction of energy, indicating a more significant improvement than the counterpart mixes containing the CRP modifier. In addition, incorporation of the CRP and NRL increased the fracture plastic zone (FPZ), resulting in increased fracture toughness. Therefore, the gradient of fracture toughness and fracture energy in the asphalt mix depends on the rubber type, content, and TFH. Although the higher CRP, NRL, and TFH improve the fracture energy and cracking resistance, they increase the crack initiation and propagation velocities, whereby the high bitumen stiffness makes the mixture more brittle than the control mixture. Caution should be exercised when selecting the content of rubber modifier and TFH for the asphalt pavements in low-temperature service. Also, there is a direct interconnection between fracture resistance and fracture energy in the mixtures containing CRP, NRL, and TFH. Such correlations can be used as the premise of predictive micro- and macro-models to evaluate mixture performance in terms of fracture resistance.

Mechanical Properties of Self-Compacting Rubberized Concrete with Different Rubber Types under Triaxial Compression

Different rubber aggregates lead to changes in the effect of stress conditions on the mechanical behavior of concrete, and studies on the triaxial properties of self-compacting rubber concrete (SCRC) are rare. In this study, 35 cylindrical specimens taking lateral stress and rubber type as variables were prepared to study the fresh properties and mechanical behaviors of SCRC under triaxial compression, where the rubber contains two types, i.e., 380 μm rubber powder and 1–4 mm rubber particles, and four contents, i.e., 10%, 20% and 30%. The test results demonstrated that SCRC exhibited a typical oblique shear failure mode under triaxial compression and had a more moderate descending branch compared with self-compacting concrete (SCC). The presence of lateral stress can significantly improve the compression properties, including initial elastic modulus, peak stress and peak strain, with an improvement range of 3%–73% for peak stress. While rubber aggregates mainly targeted the deformation abilities and toughness for improvement, and the peak strain improvement ranges were 0.1–3.1 times and 0.1–1.0 times for SCRC containing rubber powder and SCRC containing rubber particles, respectively, relative to SCC. At a high lateral stress of at least 12 MPa, the loss of strength due to the addition of rubber can be controlled within 10%, in which case the content of rubber powder and rubber particles was recommended to be at most 20% and 30%, respectively. Based on the Mohr-Coulomb theory, the failure criteria of SCRC with different rubber types were established. For analysis and design purposes, an empirical model was proposed to predict the stress-strain behavior under triaxial compression, considering the influence of different rubber content and lateral stress. The results obtained in this study can provide a valuable reference for the design and application of self-compacting rubberized concrete in practical projects, especially those involving three-way compression states and requiring high-quality deformation and energy dissipation.

Higher Adhesion Strength Over 10 N/mm Between Rubber and Fluoropolymer Film When Treated by Atmospheric Plasma-Graft Polymerization

An evaluation of the adhesion between rubber and fluoropolymer films treated by atmospheric plasma-graft polymerization is conducted to realize a low-permeation fuel rubber hose covered with fluoropolymer. The low-permeation fuel rubber hose is important for reducing vehicular evaporative emissions. Although fluoropolymers have extremely low permeability for fuel, it is difficult to bond them with other materials, such as rubber, because of their low adhesive properties. Plasma surface modification has been investigated to improve the adhesive properties of fluoropolymers. However, it is difficult to realize effective and permanent surface treatment using plasma alone. Based on the new and effective combined plasma surface-modification technique for fluoropolymer films, we previously proposed an atmospheric-pressure plasma method followed by graft polymerization of hydrophilic monomers such as acrylic acid (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> = CHCOOH). In this study, three types of rubber, isobutylene isoprene rubber (IIR), ethylene acrylic elastomer (AEM), as well as white-colored ethylene acrylic elastomer (white AEM), and two types of fluoropolymer films, denatured PFA-1 and denatured PFA-2, were prepared. The treated fluoropolymer film and rubber were adhered using vulcanized adhesion, and then the 180° peeling strength test was conducted. The results show that an average peeling strength of 12.6 N/mm and a maximum peeling strength of 15.3 N/mm, which are over 10 N/mm, are attained for the sample of vulcanized bonding of the treated denatured PFA-1 and AEM.

Study on Degradation of Medical Chlorobutyl Rubber Material by Gamma Ray Radiation

The effects of various absorbed dose amounts, especially during gamma ray radiation in the presence and absence of oxygen, on the mechanical properties and the dissolution performance of medical rubber products made of chlorobutyl rubber were investigated. From the results of physical property measurements, it was found that the reaction type of chlorobutyl rubber was not a “degradation-type”reaction, but a “crosslinking-type”reaction. Regarding the dissolution performance, the effect of oxygen was the main factor, and when gamma ray was irradiated in the absence of oxygen, it was found that the dissolution performance was almost at the same level as that of original sample. Furthermore, a compound thought to be an oxidant of the triazine vulcanizing agent, which was confirmed by LC-TofMS analysis, was detected only in the case of radiation in the presence of oxygen. This is thought to be due to the decomposition of the cross-linked bonds by the polymer radical reaction accompanying the gamma ray radiation. However, such a phenomenon was not confirmed in the absence of oxygen. These results suggest that the gamma ray sterilization of chlorobutyl rubber in the absence of oxygen enables both sterilization assurance and material degradation prevention. This method can be expected to expand its practical application to medical rubber products in the future.