Acrylic Rubber Research Articles

Experimental Tensile Strength Analysis of Different Manufacturer Oring

Importance and Purpose of Tensile Testing on ORings The tensile test on rings and especially on O-rings is primarily carried out for quality assurance reasons. The tensile test provides information about the formulation quality (evaluation of the absolute values, strength of the material, and determination of formulation changes). For example, it is not possible to detect an exchange of the polymer of compounds with different molecular weights and/or a different molecular weight distribution (e.g. highviscosity press mix by low-viscosity spray mix) by infrared spectroscopy (IR), but only by tensile testing and possibly by long-term compression set tests. Furthermore, the tensile test provides information on subsequent changes compared to the prototype condition. The Influence of Processing In the case of some O-rings, due to poor processing, it is not the strength value of the material that is determined, but the lower strength of the joining line (= confluence point of the rubber compound in the production of the O-ring in the injection mold) at which the O-ring tears. This problem depends on the material (e.g. certain acrylate rubbers), the tool and the process parameters. The joining line can usually be detected in advance by a visual and strain test or by relatively large scatter in a tensile test. Typical for the scatter in tensile tests of O-rings are 5-10%-points standard deviation related to the mean value of the elongation at break or the tensile strength. An important characteristic of good processing is the achievement of the optimum degree of vulcanization. However, there is no generally valid optimum, but this must be determined depending on the intended application of the elastomeric component. If, for example, the tear resistance is the most important material parameter for the finished product, a different degree of crosslinking or a different cross linking density must be aimed for than if, for example, a low

Effect of bias gradient delta on mechanical and tribological properties of DLC films sputtered on ACM

Diamond-like carbon (DLC) films were prepared on acrylate rubber (ACM) by varying the substrate bias voltage with bias gradient deltas of 25 V, 50 V, and 100 V during magnetron sputtering. The microstructure, mechanical and tribological properties of DLC films on ACM substrate were systematically investigated by SEM, AFM, Raman and XPS et.al in detail. The results show that the DLC film with a bias gradient delta of 25 V exhibited the most sp3 content and with the decrease of bias voltage gradient delta, the sp3 content in DLC films shows an increasing trend. The ratio of H/E increases as the bias gradient delta decreases. The results of friction tests indicated that the wear resistance of DLC films is influenced by their bias gradient deltas, surface roughness, residual stress, adhesive strength, and the ratio of H/E&H3/E2. Furthermore, decreasing the bias gradient delta resulted in a reduction in wear volume. Among the tested films, the DLC film with a bias gradient delta of 25 V exhibited the lowest CoF of 0.14 and the least wear volume of 0.98 mg, respectively. These findings suggest that the said film prepared on ACM displays excellent wear resistance.

Swelling of rubbers of different chemical natures in supercritical carbon dioxide

Objectives. To investigate the swelling of the main types of rubbers used in the rubber industry in carbon dioxide in a supercritical state (SC-CO2), in order to assess the possibility of obtaining elastomeric materials with porous structures using fluid technology, based on them.Methods. The process of swelling of rubbers in SC-CO2 and subsequent foaming was carried out according to a specially developed technique using the original installation. This is a high-pressure apparatus with transparent windows, allowing for the use of an optical technique to directly measure the geometric dimensions of samples during swelling and foaming using a digital video camera. The study of the porous structure of foamed rubbers was carried out using scanning electron microscopy.Results. The study established experimental curves of the swelling kinetics in SC-CO2 of isoprene, butadiene, styrene butadiene, ethylene propylene, chloroprene, ethylene acrylate, siloxane, and organofluorine rubbers. The influence of temperature and pressure on the rate and equilibrium degree of swelling was studied. The diffusion coefficients of SC-CO2 in rubbers of various chemical natures were also determined.Conclusions. It was shown that the equilibrium swelling degree of rubbers in SC-CO2 depends on the chemical nature of rubbers. It does not correlate with the value of their solubility parameters, changes directly proportional to the diffusion coefficient and increases with increasing temperature and pressure. It was found that irrespective of the degree of swelling in SC-CO2, all the rubbers studied are intensively foamed at a sharp pressure drop. The size of the pores formed is tens of microns: significantly smaller than the size of pores formed when chemical pore formers are used.

MAGNETIC COMPOSITES FROM RECYCLED MATERIALS

In the conditions of the increasingly accentuated development of industrial and household products, the reuse of material waste with the aim of reducing environmental pollution has become an increasingly important necessity. This study presents the obtain of flexible magnetic composites based on cotton fabrics, acrylic rubber, powder from used tires and magnetite powder. The textile support was purchased from the local market (Tesatura Iași, Romania) and was made from 100% recovered cotton fibbers, with a mass of 143g∙m-2 and an average thickness of 0.28mm. The rubber was an acrylate type (AR) (NipolR AR 51) with the next characteristics: (ρ = 1100Kg∙cm−3 at 25oC, Mooney viscosity ML (1+4) at 100oC = 55; Tg = -4 oC). The rubber powder (PW) (with more natural rubber in composition) was obtained by grinding at temperature under 10 oC from used motorcycle tires obtained from the local market. The characteristic of rubber powder was: particles size up to 100 μm, moisture content 0.25 %, density (ρ) = 1060 Kg∙m-3. Magnetite was obtained according to the literature [1]. The composites were obtained at the weight ratio of PW/AR/ (20/80) with added magnetite powder according to desired mass fraction. The materials and composites were characterized using infrared spectroscopy (FTIR), dynamic light scattering (DLS) technique, X-ray diffraction (WAXD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). These composites can be used as raw materials for smart materials in the high-tech applications in the production of the DC motors, recording apparatus, magnetic screens, radar technology, memory devices, magnetic and electromagnetic sensors, materials for medicine and environmental protection or in the electronic devices where flexibility is required.

Improvement of compatibility, thermal stability and mechanical properties of poly (phenylene oxide) (PPO) and liquid crystalline polymer (LCPA950) blends with epoxy containing acrylate rubber (ACM) as a compatibilizer

This paper proposes a new approach for improving the compatibility of liquid crystalline polymers with engineering thermoplastics. To improve compatibility and mechanical performance of poly (phenylene oxide) (PPO)/liquid crystalline polymer (LCP) A950 blends, a third component compatibilizer is incorporated into the processing step. In this work, epoxy containing acrylate rubber (ACM) is used for the compatibilization of PPO/LCPA950 blends through the chemical reaction of epoxy functional groups of the acrylate rubber with terminated carboxylic acids or hydroxyl end groups of the two phases. The compatibilization effect on the properties of PPO/LCPA950 blends is investigated by adjusting the amount of acrylate rubber. Fourier transform infrared (FTIR) spectroscopy and melt-rheological analysis were used to study the compatibilization mechanism of acrylate rubber, and the results demonstrate that acrylate rubber is capable of reacting with PPO/LCPA950 to form a chemical bonding interface. The electron microscopic images revealed a well-compatibilized microstructure of PPO/LCPA950 blends in presence of acrylate rubber with submicron-sized liquid crystalline polymer domains in the continuous poly (phenylene oxide) matrix phase, which could not be detected for immiscible PPO/LCPA950 blend. The dynamic mechanical analysis shows that PPO/LCPA950 blend with acrylate rubber exhibit greater elastic storage moduli. It was observed that blends of PPO/LCPA950 compatible with acrylate rubber showed significant increases in tensile strength as well as notched impact strength. These blends can be used in automotive industry.

Preparation and Characterization of Universal Cold-Resistant Reactive Chlorinated Acrylic Rubber and Study of Its Vulcanization Characteristics

Preparation and Characterization of Universal Cold-Resistant Reactive Chlorinated Acrylic Rubber and Study of Its Vulcanization Characteristics

Application of Modified Styrene-Acrylic-Rubber-based Latex Binder to LiCoO<sub>2</sub> Composite Electrodes for Lithium-ion Batteries

A new combination of styrene acrylic rubber (SAR) and sodium carboxymethylcellulose was developed as a water-borne binder for LiCoO2 composite electrodes operating at high voltages. Four novel SAR-based latex binders were synthesized with butyl acrylate or 2-ethylhexyl acrylate monomer and styrene via copolymerization with low and high crosslinking degrees. Composite electrodes prepared using lower-crosslinking-degree SAR binders became more stretchable and flexible. Surface analysis using electron microscopy and X-ray photoelectron spectroscopy revealed that the cycled LiCoO2 electrode was covered with approximately 10-nanometer-thick decomposition products when a conventional poly(vinylidene fluoride) binder was used. The electrodes with SAR-based binders with low cross-linkage formed a stable passivation surface during the initial cycle, and further continuous electrolyte decomposition was successfully suppressed. This passivation improved the cycle stability of LiCoO2 electrode up to 4.5 V, i.e., 87.1 % capacity retention, even after 100 cycles and suppressed self-discharge performance at 45 °C.

Surface modification of nylon 66 fiber and its reinforcement of coordination crosslinked acrylic rubber

AbstractThe interface compatibility between the surfaces of nylon 66 (PA66) fiber and the acrylic rubber (AR) is the key factor to improve the mechanical properties of the composite materials. In this study, Lewis acid (CaCl2) was firstly used to reduce the crystallinity of PA66 fiber, and then a bioinspired polydopamine (PDA) function coating was constructed on the PA66 fiber surface to act as a bridge to introduce an epoxy‐functionalized silane layer (KH560). After that, the modified PA66 fiber was introduced in the CuSO4 coordination crosslinked AR composites to further increase the mechanical performances of AR. Results showed that Lewis acid could significantly reduce the surface crystallinity of PA66 fiber, the PDA coating has successfully coated the fiber surface. And SEM results showed, the interfacial compatibility between the fiber and rubber was obviously improved. Compared with the unmodified PA66 fiber filled AR composites, the tensile strength, modulus and hardness of the modified PA66 fiber filled AR composites were increased by 95%, 49%, and 16% respectively.

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.

Miscibility, Hierarchical Structures, and Enhanced Mechanical Properties of Acrylic Rubber by the Formation of a Chemically and Physically Crosslinked Partially Miscible Interpenetrating Polymer Network with Poly(vinylidene fluoride)

Miscibility, Hierarchical Structures, and Enhanced Mechanical Properties of Acrylic Rubber by the Formation of a Chemically and Physically Crosslinked Partially Miscible Interpenetrating Polymer Network with Poly(vinylidene fluoride)

Composites based on cotton fabrics, acrylic rubber and powder from used tires: thermal and electrical characterization

Composites based on cotton fabrics, acrylic rubber and powder from used tires: thermal and electrical characterization

Acrylic Rubber-Reinforced Halloysite Nanotubes/Carbon Black Hybrid Fillers for Oil Seal Applications: Thermal Stability and Dynamic Mechanical Properties

In this study, we show that adding halloysite nanotubes (HNT) to carbon black (CB)-packed acrylic rubber (ACM) composites improves their thermal properties. The thermo-oxidative stability, thermal stability, and dynamic mechanical properties of ACM composites (filled simply with 70 phr CB) and ACM hybrid composites comprising a fixed amount of CB (60 phr) and a variable amount of halloysite nanotubes (HNT) (2, 4, 6, 8, and 10 phr) were investigated. As evidenced by the oxidation induction time analysis, hybrid structures support a higher degree of antioxidation in composites reinforced with twin fillers than composites reinforced just with CB. ACM composites with dual fillers had greater breakdown temperatures (temperatures at 10% weight loss (T10) and 50% weight loss (T50)) and char residue concentration at 600°C than ACM conventional composites, according to thermogravimetric tests. The activation energy of the thermal disintegration of ACM composites, as determined by the Kissinger and Flynn–Wall–Ozawa techniques, shows that the addition of HNT improves the thermal stability of ACM composites. The storage modulus of ACM composites was increased by 79 percent at 30°C when 10 phr of black filler was replaced with 6 phr of tubular HNT, according to additional viscoelastic experiments.

Styrene-Lauryl Acrylate Rubber Nanogels as a Plugging Agent for Oil-Based Drilling Fluids with the Function of Improving Emulsion Stability.

With the exploration and development of unconventional oil and gas, the use frequency of oil-based drilling fluid (ODF) is increasing gradually. During the use of ODFs, wellbore instability caused by invasion of drilling fluid into formation is a major challenge. To improve the plugging property of ODFs, nano-sized poly(styrene-lauryl acrylate) (PSL) rubber nanogels were synthesized using styrene and lauryl acrylate through soap-free emulsion polymerization method and were characterized using FTIR, NMR, SEM, TEM, particle size analysis and TGA. The results show that, due to good dispersion stability and oil-absorbing expansion ability, the PSL rubber nanogels have a wide range of adaptations for nano-scale pores to deposit a layer of dense filter cake on the surface of filter paper with various pore diameters, reducing the filtration of mineral oil and W/O emulsion significantly. Due to the unique wettability, the PSL rubber nanogels can be adsorbed stably at the oil-water interface and form a dense granular film to prevent droplets coalescing, which improves the emulsification stability of W/O emulsion. Furthermore, the PSL rubber nanogels are soap-free and compatible with ODFs without foaming problems. The PSL rubber nanogels can increase the hole-cleaning performance of ODFs by raising viscosity and yield point. The PSL rubber nanogels outperformed hydrophobic modified nano silica and polystyrene nanospheres in plugging and filtration reduction. Therefore, the PSL rubber nanogels are expected to be used as a new plugging agent in oil-based drilling fluid. This research provide important insights for the use of organic nanogels in ODFs and the optimization of plugging conditions.

Characterization and study of the vulcanization characteristics of ultra‐cold‐resistant reactive chlorinated acrylic rubber prepared by emulsion polymerization

AbstractIn a system initiated by potassium persulfate, an ultra‐cold‐resistant reactive chlorinated resin rubber was synthesized by emulsion polymerization. In this emulsion polymerization, ethyl acrylate and butyl acrylate were used as the main components of the rubber monomer. 2‐Methoxyethyl acrylate was used as a cold‐resistant monomer, and vinyl chloroacetate was used as a vulcanized monomer. Fourier transform infrared spectroscopy, thermogravimetry–gas chromatography–mass spectrometry, 1H NMR, 13C NMR and other rubber detection standards were used to characterize the structure and properties of the synthetic acrylate rubber. Studies showed that acrylate rubber was synthesized by emulsion polymerization, and each monomer achieved random copolymerization with high conversion. The synthetic acrylate rubber has excellent low‐temperature resistance (the brittleness temperature is −36.5 °C). In addition, the rubber has excellent mechanical properties and a high vulcanization speed and is a fast‐vulcanizing acrylic rubber. © 2022 Society of Industrial Chemistry.

Monitoring of shear heating effects during injection molding of rubber to improve the process control

This work aims to get new insights into the “process monitoring tool” proposed by the authors for the online monitoring of the shear heating phenomenon during injection molding of technical rubber parts. The online monitoring is based on direct measurement of the surface rubber temperature (shear heating temperature, TSH) by an infrared thermal camera of the rubber as it leaves the extruder barrel of the injection molding machine. The measured rubber temperature is a process indicator giving the thermal history of the rubber compound injection and process safety. Therefore, this fast process control is applied to industrial applications to investigate the processing behavior of ethylene acrylate (AEM) rubber compounds. In particular, the relationships between TSH vs injection pressure, vs injection speed, vs screw speed rotation and vs screw length over diameter ratio (L/D ratio) and vs AEM rubber compound properties variation due to exceeding the shelf life are investigated. The results show that TSH is manly influenced by the screw L/D ratio, followed by injection pressure and screw speed rotation (especially if are set to higher levels), whereas the injection speed is the least effective parameter to reduce TSH. Furthermore, a previously found robust correlation between the shear heating parameter (ηSH) and the minimum torque measured in rheometric laboratory tests (ML) is used to show the noteworthy deviation from the proportional trend when the AEM rubber compound exceeded it shelf life. Therefore, the coefficient of determination of {text{log}}eta_{{{text{SH}}}} vs ML curves provides a good indication of process stability, while it is running.

Influence of various factors on surface properties of elastomeric materials based on nitrile butadiene rubbers

Objectives. The influence of the technological additive content and accelerated aging conditions on the surface energy and elastic-strength properties of nitrile butadiene rubbers with an average acrylic acid nitrile content and rubbers based on them were studied in the paper.Methods. The free surface energy of the samples was determined under the standard conditions and in the accelerated aging conditions with the use of the Owens, Wendt, Rabel, and Kaelble method.Results. It was shown that the elastomeric materials surface energy is influenced by surfactants such as rosin and stearic acid, which are typical ingredients of rubber compounds. It was also found that the thermal aging effect on the physical and mechanical properties of rubbers based on nitrile butadiene rubbers depends on the method of rubber isolation from latex and on the nature of the surfactant components in the samples.Conclusions. The analysis of the results obtained shows that the change in the vulcanizates physical and mechanical properties, depending on the technological additive content and the temperature effect, occurs along with a change in the critical surface tension.

Predictive Model of Dynamic Mechanical Properties of VE Damper Based on Acrylic Rubber–Graphene Oxide Composites Considering Aging Damage

AbstractBecause shock absorbers are an important component of high-rise buildings, it is essential to be able to detect damage to them. Viscoelastic (VE) dampers, as a common shock absorber, direct...

Curing Efficiency of Novolac-Type Phenol–Formaldehyde Resins from Viscoelastic Properties

The curing performance of a homogeneous set of different grades of novolac-type phenol–formaldehyde (PF) resins having different structures is analyzed. The PF resins have a statistical ortho/para substitution at aromatic rings and contain from 5 to 15 wt % hexamethylenetetramine (HMTA) as a hardener. Moreover, the different analyzed grades are PF resins differently modified by addition of boron/phosphorous compounds, or an acrylic rubber, or silicone and xylene/phenol copolymers, or introduction of aralkyl modifications. The curing behavior is compared with that of an unmodified PF resin in which the cross-linking agent (HMTA) is added into the molten polymer to guarantee a good dispersion according to the hexamine adduct phenolic (HAP) technology. The effect of the different modifications is probed by rheological measurements during curing under isothermal conditions. Under similar curing conditions, the modified resins show different curing performances and lower stiffness with respect to the unmodified Ph resin obtained by HAP technology. A method to quantify the curing performance is introduced and suggested based on two relevant parameters derived from rheological measurements, the “curing ratio” that indicates the efficiency to generate the thermal-induced three-dimensional network and a “maximum curing rate” that is related to the cross-linking reaction rate. The results allow classifying the resins as belonging to different classes, depending on the combination of the curing ratio and curing rate.

DEVELOPMENT OF TEXTILE-RUBBER COMPOSITE MATERIALS USING RECYCLED RUBBER AND TEXTILES WITH APPLICATIONS IN INDUSTRY

This paper study methods to obtain composite materials based on recycled rubber from End-of-Life tires and scrap textile. Rubber particles was obtained by industrial shredding procedures and separated by dimension, using sieves. Recycled cotton weave was obtained from scrap cotton textiles. The composite material was produced mixing the recycled rubber powder with a solution of acrylate rubber (AR), (NipolR AR 51) in acetone/ethyl acetate, then coating that composition on a 100% recycled cotton weave. After application, the composite was dried in a dryer with ventilation. The final composite material will be chemical characterized. Attempts will be made to determine whether the composite can be used as isolation material with temperature dissipation characteristics.

Influence of Processing Techniques on Microhardness and Impact Strength of Conventional and Reinforced Heat Cured Acrylic Resin: A Comparative Study

This study determined and compared the influences of various processing techniques including air circulating oven (ACO), dry heat oven (DHO) and water bath (WB) on the impact strength (IS) and microhardness (HV) of the conventional heat cure acrylic resin (CHCAR) and rubber reinforced heat cure acrylic resin (RRHCAR). Samples were fabricated using CHCAR (control Group A; n=114) and RRHCAR (experimental Group B; n=114). Group A and B were further divided into subgroups according to processing techniques: ACO, DHO and WB (n=38 each) for both testing variables microhardness and impact strength (n=19 each). Charpy testing machine and Vickers microhardness tester were utilized. Analysis of variance was applied to determine the presence of significant differences among processing techniques while P-value ≤ 0.05 was considered as significant. Water bath (P-value [0.001) and DHO technique (p-value [0.001) showed significant differences between both groups� impact strength and microhardness. Microhardness of group A and B showed a significant difference (p-value 0.002) when processed by ACO. Impact strength and micro hardness were improved in RRHCAR compared to CHCAR processed by ACO and DHO in comparison to WB technique. Rubber reinforced heat cure acrylic resin revealed improvement in the impact strength and microhardness. The air circulating oven exhibited highest microhardness in both testing materials. Dry heat oven showed improved values of impact strength in conventional heat cure acrylic resin.