Artículos de revistas: "Elastomeric thermoplastic"

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Matsuda, Akihiro y Shigeru Kawahara. "Applicability of Thermoplastic Elastomers to Impact Load Reduction in Sports Equipment". Proceedings 49, n.º 1 (15 de junio de 2020): 163. http://dx.doi.org/10.3390/proceedings2020049163.

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In this paper, mechanical properties of thermoplastic elastomers were investigated to expand the applicability of thermoplastic elastomers to the impact load reduction for the sports equipment. The thermoplastic elastomers show both thermoplastic and elastomeric properties. These are expected to apply to the impact load reduction in sports equipment due to good processability and less-smell. In this study, thermoplastic elastomers were applied for monotonic and cyclic tensile loading tests. The thermoplastic elastomer (TPE) materials in this study were newly developed for the specific purpose of impact load reduction. The nonlinear hyperelastic model considering the viscosity and damage model was applied to the tensile loading test results. finite element analysis (FEA) results of TPE specimens with periodic geometric shapes to reduce impact load were investigated.

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Kresge, E. N. "Polyolefin Thermoplastic Elastomer Blends". Rubber Chemistry and Technology 64, n.º 3 (1 de julio de 1991): 469–80. http://dx.doi.org/10.5254/1.3538564.

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Abstract Thermoplastic elastomers based on blends of polyolefins are an important family of engineering materials. Their importance arises from a combination of rubbery properties along with their thermoplastic nature in contrast to thermoset elastomers. The development of polyolefin thermoplastic elastomer blends follows somewhat that of thermoplastic elastomers based on block copolymers such as styrene-butadiene-styrene triblock copolymer and multisegmented polyurethane thermoplastic elastomers which were instrumental in showing the utility of thermoplastic processing methods. Polyoleflns are based on coordination catalysts that do not easily lend themselves to block or multisegmented copolymer synthesis. However, since polyolefins have many important attributes favorable to useful elastomeric systems, there was considerable incentive to produce thermoplastic elastomers based on simple α-olefins by some means. Low density, chemical stability, weather resistance, and ability to accept compounding ingredients without compromising physical properties are highly desirable. These considerations led to the development of polyolefin thermoplastic elastomer blends, and two types are now widely used: blends of ethylene-propylene rubber (EPM) with polypropylene (PP) and blends of EPDM and PP in which the rubber phase is highly crosslinked. This article reviews the nature of these blends. Both physical and Theological properties are very dependent on the morphology and crosslink density of the blend system. Moreover, the usefulness of practical systems depends extensively on compounding technology based on added plasticizers and fillers.

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Schönherr, Holger, Willy Wiyatno, John Pople, Curtis W. Frank, Gerald G. Fuller, Alice P. Gast y Robert M. Waymouth. "Morphology of Thermoplastic Elastomers: Elastomeric Polypropylene". Macromolecules 35, n.º 7 (marzo de 2002): 2654–66. http://dx.doi.org/10.1021/ma010959m.

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Abdou-Sabet, Sabet y Raman P. Patel. "Morphology of Elastomeric Alloys". Rubber Chemistry and Technology 64, n.º 5 (1 de noviembre de 1991): 769–79. http://dx.doi.org/10.5254/1.3538589.

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Abstract The field of thermoplastic elastomers has shown an explosive growth with the successful commercialization of elastomeric alloys (EAs) in 1981, based on the original work of Coran, Das, and Patel on dynamic vulcanization and the discovery of preferred cure system by Abdou-Sabet and Fath. These discoveries have led to the development of commercial products having true elastomeric properties while maintaining excellent thermoplastic processing. The success of EAs in the marketplace has led to the introduction of new products by Monsanto and others at a rate of 60 products per year in the last half of the eighties. Elastomeric alloys have been characterized as compositions containing rubber particulate domains approximately 1–2 µm in diameter in a matrix of thermoplastic resin. Such dispersed phase morphology has not been widely accepted, especially when it came to explaining the true elastomeric properties of the soft elastomeric products, i.e. 64 and 55 Shore A hardness products. Interaction among the rubber particles leading to a network of vulcanized elastomer phase that gave the appearance of two continuous networks has been proposed. In this paper, the morphology of EPDM/polypropylene elastomeric alloys is examined with some detail, and evidence leading to dispersed phase morphology is provided. There are several variables to such an investigation which can be grouped under the following headings: 1. Molecular weight of EPDM and polypropylene (PP). 2. Ratio of EPDM to PP. 3. Crosslinked or uncrosslinked blend. 4. Degree of crosslinking. 5. Type of crosslinks. 6. Typical and commercial products. It is not the subject of this paper to review the morphology of different binary polymer blends, which have been extensively covered in the literature. It can be concluded that a variety of morphologies can be obtained, however, depending on the mixing conditions, polymer ratios, relative surface energies of the polymer pair, and viscosities and molecular weights of the two polymers. In this study, the mixing conditions were kept similar as much as possible to eliminate the possibility of morphological changes as a function of the applied mixing intensity as influenced by shear rate, mixing time, and temperature.

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Ellul, Maria D. y Yuichi Hara. "SPECIALTY POLYMERS AND DYNAMICALLY VULCANIZED ALLOYS FOR ULTRA LOW AIR PERMEABILITY TIRE INNER LINERS". Rubber Chemistry and Technology 91, n.º 4 (1 de octubre de 2018): 751–56. http://dx.doi.org/10.5254/rct.18.81542.

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ABSTRACT Brominated poly(isobutylene-co-p-methylstyrene) specialty elastomers (Exxpro™) or BIMSM (ASTM name) are unique in their low permeability to air combined with a low glass transition temperature, Tg,, and a saturated backbone; making them a choice elastomer for applications requiring air barrier properties. This behavior derives from the geminal dimethyl groups on every other carbon of the polyisobutylene (PIB) backbone causing modification in the bond angles of these chains, allowing them to pack more closely than other saturated hydrocarbons. Dynamically vulcanized alloys (DVAs), also known as thermoplastic vulcanizates (ASTM 5046) of Exxpro™ elastomer and nylon thermoplastic (Exxcore™ DVA), also referred to as BIMSM-Nylon DVA, have much lower permeability to air than BIMSM. The challenge is to maintain the elastomeric nature of the material by having a major volume fraction of BIMSM rubber, while approaching the excellent air barrier characteristics of nylon at a lower volume fraction of the thermoplastic matrix than the dispersed rubber phase. This problem was solved by introducing a functional oligomer that chemically reacts with the nylon. BIMSM-Nylon DVAs consist of submicron sized domains of BIMSM elastomer of tailored molecular structure, in a matrix of nylon and a chemically bound oligomer viscosity modifier. Thus, a reasonable elastomeric modulus is achieved, and the key performance properties of superior air barrier as well as low temperature fatigue resistance are well satisfied. Tire inner liners are the focused end use of BIMSM-Nylon DVA, where the novel material characteristics are targeted to achieve excellent air impermeability, durability, and lightweighting. Optimal combination of these properties is expected to deliver improved performance and sustainable benefits such as fuel economy and lower tire maintenance costs.

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Abdou-Sabet, S., R. C. Puydak y C. P. Rader. "Dynamically Vulcanized Thermoplastic Elastomers". Rubber Chemistry and Technology 69, n.º 3 (1 de julio de 1996): 476–94. http://dx.doi.org/10.5254/1.3538382.

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Abstract Thermoplastic elastomers (TPEs) exhibit the functional properties of conventional thermoset rubber, yet can be processed on thermoplastic fabrication equipment. The great majority of TPEs have hetero-phase morphology, whether the TPE is derived from block copolymers, rubber-plastic compositions or ionomers. Generally speaking, the hard domains (or the ionic clusters) undergo dissociation at elevated temperatures, thus allowing the material to flow. When cooled, the hard domains again solidify and provide tensile strength at normal use temperatures. The soft domains give the material its elastomeric characteristics. In this review article, the focus is on rubber-plastic polymer compositions as a group of TPEs which have achieved significant growth in the marketplace in the last two decades. The growth has been primarily in the nonpolar (olefinic) elastomer/polyolefin thermoplastic materials because of the wide range of products generated, their performance and their significant acceptance by the automotive sector in applications requiring elastic recovery. The field of TPEs based on polyolefin rubber-plastic compositions has grown along two distinctly different product lines or classes: one class consists of a simple blend and classically meets the definition of a thermoplastic elastomeric olefin (TEO), commonly called a thermoplastic polyolefin (TPO) in earlier literature. In the other class, the rubber phase is dynamically vulcanized, giving rise to thermoplastic vulcanizates (TPVs), named elastomeric alloys (EAs) in some previous literature. Both the simple blends and the dynamically vulcanized TPEs have found wide industrial application. It is the dynamically vulcanized TPE that has the performance characteristics required for true thermoset rubber replacement applications. The first TPE introduced to the market based on a crosslinked rubber-plastic composition (1972) was derived from W. K. Fisher's discovery of partially crosslinking the EPDM phase of EPDM/polypropylene (PP). Fisher controlled the degree of vulcanization by limiting the amount of peroxide, to maintain the thermoplastic processability of the blend. Crosslinking was performed while mixing, a process known as dynamic vulcanization. It is worth noting, however, that the dynamic vulcanization process and the first crosslinked EPDM/PP composition were discovered independently by Gessler and Haslett and by Holzer, Taurus and Mehnert in 1958 and 1961, respectively. Significant improvement in the properties of these blends was achieved in 1975 by Coran, Das and Patel by fully vulcanizing the rubber phase under dynamic shear while maintaining the thermoplasticity of the blend. These blends were further improved by Abdou-Sabet and Fath in 1977 by the use of phenolic curatives to improve the rubber-like properties and the flow (processing) characteristics.

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Kozłowska, A. y M. Piatek-Hnat. "Evaluation of Influence of the Addition Nanofillers on the Mechanical and Thermal Properties Terpolymers Ester-Ether-Amide". Archives of Metallurgy and Materials 59, n.º 1 (1 de marzo de 2014): 237–39. http://dx.doi.org/10.2478/amm-2014-0038.

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Abstract The results of studies of mechanical and thermal properties of synthesized elastomeric nanocomposites have been presented. An elastomeric multiblock terpoly(ester-b-ether-b-amide)s as polymeric matrix and nanoparticles SiO2 i TiO2 used as fillers. It was shown that the introduction of multiblock thermoplastic elastomer matrix of SiO2 and TiO2 nanoparticles allows to obtain nanocomposite materials with improved mechanical properties compared to the terpolymer before modification. An increase in glass transition temperature, which has a positive effect for the processing of terpolymers.

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Rahmatabadi, Davood, Mohammad Aberoumand, Kianoosh Soltanmohammadi, Elyas Soleyman, Ismaeil Ghasemi, Majid Baniassadi, Karen Abrinia, Ali Zolfagharian, Mahdi Bodaghi y Mostafa Baghani. "A New Strategy for Achieving Shape Memory Effects in 4D Printed Two-Layer Composite Structures". Polymers 14, n.º 24 (13 de diciembre de 2022): 5446. http://dx.doi.org/10.3390/polym14245446.

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In this study, a new strategy and design for achieving a shape memory effect (SME) and 4D printed two-layer composite structures is unveiled, thanks to fused deposition modeling (FDM) biomaterial printing of commercial filaments, which do not have an SME. We used ABS and PCL as two well-known thermoplastics, and TPU as elastomer filaments that were printed in a two-layer structure. The thermoplastic layer plays the role of constraint for the elastomeric layer. A rubber-to-glass transition of the thermoplastic layer acts as a switching phenomenon that provides the capability of stabilizing the temporary shape, as well as storing the deformation stress for the subsequent recovery of the permanent shape by phase changing the thermoplastic layer in the opposite direction. The results show that ABS–TPU had fixity and recovery ratios above 90%. The PCL–TPU composite structure also demonstrated complete recovery, but its fixity was 77.42%. The difference in the SME of the two composite structures is related to the transition for each thermoplastic and programming temperature. Additionally, in the early cycles, the shape-memory performance decreased, and in the fourth and fifth cycles, it almost stabilized. The scanning electron microscopy (SEM) photographs illustrated superior interfacial bonding and part integrity in the case of multi-material 3D printing.

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Madkour, Tarek M. y James E. Mark. "Properties of thermoplastic elastomeric polypropylene". Polymer Bulletin 39, n.º 3 (septiembre de 1997): 385–91. http://dx.doi.org/10.1007/s002890050163.

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10

Legge, N. R. "Thermoplastic Elastomers—Three Decades of Progress". Rubber Chemistry and Technology 62, n.º 3 (1 de julio de 1989): 529–47. http://dx.doi.org/10.5254/1.3536257.

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Abstract In these three decades of progress, thermoplastic elastomers have risen in 1987 to a position of tenth in the order of commercial thermoplastic sales in the U.S.A., with a growth rate, 1986–1987, of 9.7%. It is very probable that the quantity shown for 1987 sales, 441 million pounds, is low, since it is well known that the largest producer of styrenic TPEs does not report offtake data. Much of the styrenic TPE goes to the adhesive industry, which also is very secretive in regard to materials consumption information. Thus, the 1986–1987 reported growth rate of 9.7% is on the low side. Another indicator of progress in the growth of TPEs has been illustrated by the number of product introductions from January 1986 to June 1987. During that period, TPEs led the major thermoplastics with the introduction of 270 new product types, and the nylons were a close second with 250. A third estimate of the explosive growth in TPEs may be seen in Table V which lists the number of manufacturers of TPEs in 1975, 1985, and 1987, increasing from 10 to 28 to 50. To summarize, the present thermoplastic elastomers, now high-volume commercial products, had roots in the chemistry and technology of polymers in the 1920's. Throughout the history of the “Roots” period one can detect precursor events from which several TPEs could have been foreseen. In each of the three decades of progress, major advances were made in the technology, physical properties, availability, and utilization of TPEs. The numbers of these increased in each succeeding period. Several paradigms appear in this review, for example: 1. The triblock styrene-diene A-B-A copolymers, morphology, and elastomeric character, in the first decade. 2. The copolyesters with (A−B)n morphology and greatly enhanced physical properties in the second decade. 3. The dynamically-vulcanized blends of EPDM and PP, followed in time by the concept of compatibilization to permit practical blends of NBR and PP in the third decade. Throughout these periods, growth was catalyzed by the favorable economics of manufacturing finished elastomeric products via low-cost thermoplastic processing techniques as compared with thermoset rubber processes. The reuse of scrap also provided a major incentive. In addition to these, the concept of component integration is now showing a path toward even more cost reduction incentives. New applicational areas continue to appear. One of these, blending relatively small amounts of TPEs with existing large volume thermoplastics, promises to provide extremely large offtakes of TPEs in the next decade. I am sure that the numbers of papers presented in symposia at meetings of the Rubber Division of the American Chemical Society confirm the continued explosive growth of TPEs we have seen in these past three decades.

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López Manchado, Miguel A. y José M. Kenny†. "Use of Benzene-1,3-Bis(Sulfonyl)Azide as Crosslinking Agent of TPVs Based on EPDM Rubber—Polyolefin Blends". Rubber Chemistry and Technology 74, n.º 2 (1 de mayo de 2001): 198–210. http://dx.doi.org/10.5254/1.3544944.

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Abstract The use of innovative crosslinking agents for the preparation of thermoplastic vulcanizates (TPVs) is investigated. In this preliminary study, the most common TPV systems, based on polypropylene (iPP) and ethylene—propylene—diene terpolymer rubber (EPDM) blends, are studied. Among typical vulcanization agents, only the peroxides are able to crosslink saturated elastomers, however, they present the disadvantage that give rise to chain scission of the thermoplastic matrix. For this reason, the main goal of the present study is to investigate a new vulcanization agent for elastomeric matrices, which also permit the dynamic vulcanization process in their blends with polyolefins. This agent is based on a diazide derivative, benzene-1,3-bis(sulfonyl)azide that, for the specific behavior of the sulfonyl azide group, allows its interaction with the carbon—hydrogen bonds of the elastomeric phase and of the polyolefin. The study includes the dynamic vulcanization of PP—EPDM blends and their rheological, mechanical and thermal characterization. A comparison with traditional TPVs prepared with sulfur as vulcanization agent is also presented.

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Shannon, Zina. "Thermoplastic Elastomeric Polyolefins in Film Applications". Journal of Plastic Film & Sheeting 12, n.º 2 (abril de 1996): 149–56. http://dx.doi.org/10.1177/875608799601200207.

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Peterson, D. E. y P. D. Agrawal. "Foam Extrusion of Thermoplastic Elastomeric Alloys". Cellular Polymers 7, n.º 6 (noviembre de 1988): 475–86. http://dx.doi.org/10.1177/026248938800700603.

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The new elastomeric alloys such as Monsanto's Santoprene thermoplastic rubber (A class of TPE) can be formed during extrusion by the use of a chemical blowing agent or by the use of a fluorocarbon blowing agent to provide products with characteristics superior to foamed vulcanised rubber. These materials offer more precise dimensional design tolerances, better process control and reprocessing of scrap. Other advantages are in heat weldabiliry, better compression set and compressive load.

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Gleichweit, Eva, Christian Baumgartner, Reinhard Diethardt, Alexander Murer, Werner Sallegger, Dietmar Werkl y Stefan Köstler. "UV/Ozone Surface Treatment for Bonding of Elastomeric COC-Based Microfluidic Devices". Proceedings 2, n.º 13 (11 de diciembre de 2018): 943. http://dx.doi.org/10.3390/proceedings2130943.

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Reliable bonding of microstructured polymer parts is one of the major challenges in industrial fabrication of microfluidic devices. In the present work, the effects of a UV/ozone surface activation on the bonding process were investigated for the combination of a commonly used thermoplastic cyclic olefin copolymer (COC) with an elastomeric COC (eCOC) as a new thermoplastic elastomer material. Bonding was studied using two-component injection molded parts of COC and eCOC, together with microfluidic COC chips. Surface activation and bonding process parameters were optimized and bond strengths were characterized by the wedge test method. The results showed that strong bonding of this polymer materials combination can be achieved at temperatures significantly below the bulk glass transition temperature of COC.

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Puskas, Judit E. y Gabor Kaszas. "Polyisobutylene-Based Thermoplastic Elastomers: A Review". Rubber Chemistry and Technology 69, n.º 3 (1 de julio de 1996): 462–75. http://dx.doi.org/10.5254/1.3538381.

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Abstract This paper honours the 40th anniversary of the discovery of the living polymerization concept. Polymeric materials exhibiting both thermoplastic and elastomeric characteristics have a variety of unique properties which makes them valuable articles of commerce. Such thermoplastic elastomers or TPEs, schematically represented in Scheme 1, are block copolymers — ABA linear triblock, A(BA)n linear alternating block or (AB)n−X radial block, where A is a thermoplastic glassy block with a high glass transition temperature (Tg) while B is an elastomeric block with a low Tg. These TPEs behave like vulcanized rubbers at room temperature and like thermoplastics at elevated temperatures. Thus the materials can be melt extruded like plastics, while retaining their beneficial rubbery properties upon cooling. This ability is not only of advantage during processing, but allows the materials to be reprocessed, which is of importance from both the material savings and the environmental protection point of view. These block copolymers exhibit physical behavior similar to reinforced elastomers, or in other words, they behave as vulcanized rubbers but without the need of chemical vulcanization. Polymers having such dual nature have been commercialized for some time [Shell's ABA type Kraton®s; where A is polystyrene (PSt) and B is polybutadiene (PBD) or polyisoprene (PIP)]. In order to have good physical properties of these block-type TPEs, a high degree of microphase separation between the rubbery and glassy phases and the formation of “physical crosslinks” by the glassy segments are required. It is therefore of utmost importance for these blocks to have nearly uniform or narrow molecular weight distribution (MWD). The synthesis of nearly uniform polymers was made possible by the discovery of the living polymerization concept by M. Szwarc, which in turn made possible the synthesis and commercialization of the Kraton® series. While Kraton®s exhibit the above described fundamental duality of thermoplasticity and elasticity, they also possess certain undesirable characteristics such as poor oxidative stability due to the highly unsaturated nature of the elastomeric blocks. To overcome this problem the Kraton G® series (Shell) have been developed by hydrogenating the PBD rubbery segment. It should also be mentioned here that hydrogenation of solution and emulsion SBRs produced materials with TPE properties. In this case phase separation was achieved between the rubbery and glassy/crystalline phases leading to reasonably good physical strength (up to 10 MPa), in spite of the lack of uniformity in these polymers. At the same time, the synthesis of block TPEs with polyisobutylene (PIB) rubbery segments became a desirable objective because of the superior oxidative, chemical and thermal stability, and the outstanding barrier and damping properties of PIB. However, PIB can be made only by carbocationic polymerization. Just a decade ago living carbocationic polymerization was declared to be impossible due to the highly reactive nature of the active centers. Today, both the living carbocationic polymerization of isobutylene (IB) and other olefins, and the synthesis of PIB-based TPEs by living polymerization are a reality. This paper will review the most important milestones that led to this chemical and technological achievement, and discuss the characterization and some applications of these new materials.

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WIELEBA, Wojciech y Mariusz OPAŁKA. "STATIC FRICTION OF REVERSE STEEL–ELASTOMER SLIDING PAIRS". Tribologia 279, n.º 3 (1 de julio de 2018): 147–51. http://dx.doi.org/10.5604/01.3001.0012.7023.

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Sliding cooperation of materials with different hardness (deformability), e.g., a polymeric material cooperating with metallic materials, occurs in machine elements in one of the following two variants: a conventional pair or a reverse pair. In the case of the conventional sliding pair, the deformation area (contact area) of the sliding materials does not move on the surface of the polymer element during their cooperation. In the case of reverse pairs, the contact surface changes its position when moving on the surface of the polymer element. Depending on the variant of the sliding pair, the differences in the friction and wear process of polymer material can be observed. Tribological investigations of chosen sliding pairs (elastomer on steel or steel on elastomer) in the static friction were carried out on the rig. The polymeric materials selected for the tests were thermoplastic elastomers TPU, PUR, and silicone rubber SI. These materials co-operated with C45 steel in the different contact pressures (p = 0.1 – 0.26 MPa) under dry friction or mixed lubrication conditions (hydraulic oil Hipol HLP-68). Based on the recorded value of the friction force Ft, the values of static coefficients of friction μstat were determined. The test results showed a significant influence of the variant of the combination of materials (metal-polymer or polymer-metal) on the value of the friction coefficient. In all tested pairs in which steel sample (pin) slid against elastomeric plates, the friction coefficient was higher than in the case when the elastomeric sample (pins) cooperated with steel counterfaces (plates). The main reason is the considerable value of the deformation component of the friction force. This is probably due to the displacement of the elastomer deformation area in its surface layer and energy dissipation as a result of stress-strain hysteresis in the elastomeric material, as in the case with reversed pairs.

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Kühne, Friederike, Maurus Biedermann, Angela Eicher, Florian Felder, Stefan Sander, Roman Schmidt, Saskia Lehmann et al. "Characterisation of Elastomers as Food Contact Materials–Part 1: Quantification of Extractable Compounds, Swelling of Elastomers in Food Simulants and Release of Elements". Molecules 26, n.º 2 (19 de enero de 2021): 509. http://dx.doi.org/10.3390/molecules26020509.

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Elastomers are not a uniform class of materials but comprise a broad spectrum of chemically different polymers. Sealing gaskets, gloves, teats, conveyor belts and tubing are examples of elastomers being used as food contact materials (FCMs). Ten elastomer samples were evaluated with respect to the content of extractable compounds, migration of substances into ethanolic food simulants, swelling in food simulants and release of elements in different food simulants. The number of extractable substances <1000 Da was determined by comprehensive two-dimensional gas chromatography coupled with flame ionisation detection (GC × GC–FID) analysis of tetrahydrofuran (THF) extracts. The number of signals ranged from 61 (a thermoplastic elastomer (TPE)) to 690 (a natural rubber/styrene-butadiene-rubber blend (NR/SBR)). As for risk assessment, the decisive factor is which substances reach the food. The extent of substances that migrate into ethanolic food simulants was investigated. Elastomer FCMs can be the source of food contamination with heavy metals. Notably, contamination with lead was detected in some samples investigated in this study. It was shown that food simulants harbour the potential to morphologically alter or even disintegrate elastomeric materials. The results presented here highlight the importance to carefully choose the elastomer type for the intended use as FCMs as not every application may prove safe for consumers.

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Gupta, Samik, Parnasree Maiti, Kumar Krishnamoorthy, Raja Krishnamurthy, Ashok Menon y Anil K. Bhowmick. "Effect of Silica Nanoparticles on Reinforcement of Poly(phenylene ether) Based Thermoplastic Elastomer". Journal of Nanoscience and Nanotechnology 8, n.º 4 (1 de abril de 2008): 2114–26. http://dx.doi.org/10.1166/jnn.2008.18268.

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Reinforcement of a novel poly(phenylene ether) (PPE) based thermoplastic elastomer (TPE), i.e., styrene-ethylene-butylene-styrene (SEBS)/ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied to develop a reinforced thermoplastic elastomer or thermoplastic vulcanizate (TPV). An effort was made to reinforce selectively the elastomeric dispersed phase of EVA by silica nanoparticles and silica sol–gel precursors, like alkoxy orthosilanes, using twin-screw extrusion and injection molding processes. Improvement of tensile strength and percent elongation at break was observed both with silica nanoparticles and tetraethoxy orthosilane (TEOS). Addition of TEOS transformed the dispersed EVA lamellar morphology into semispherical domains as a consequence of possible crosslinking. Soxhlet extraction was done on the silica and TEOS reinforced materials. The insoluble residues collected from both the silica and TEOS reinforced samples were analyzed in detail using both morphological and spectroscopic studies. This extensive study also provided an in-depth conceptual understanding of the PPE based TPE behavior upon reinforcement with silica nanoparticles and silica sol–gel precursors and the effect of reinforcement on recycling behavior.

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Kulachenkova, Z. A., A. K. Bulkina, S. A. Kilin, A. V. Rumyantseva, I. V. Baranets, Zh A. Otvalko y S. K. Kurlyand. "The Creation of Biologically Inert Elastomeric Material Based on Thermoplastic Elastomer Blends". International Polymer Science and Technology 44, n.º 12 (diciembre de 2017): 63–66. http://dx.doi.org/10.1177/0307174x1704401211.

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Composites based on polyvinyl acetate, a copolymer of ethylene with a low vinyl acetate content, a divinyl styrene thermoplastic elastomer, and 3,4-isoprene rubber were developed for the production of sample specimens for children's creative play. Wide-ranging tests were carried out; results showed the total compliance of the developed composite materials with RFP and hygiene requirements.

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Gordeeva, I. V., Tatiana V. Dudareva, I. A. Krasotkina, Vadim G. Nikol'skii, Yulia A. Naumova, M. Yu Sinkevich y V. A. Lobachev. "Methodological Aspects of Evaluating the Particle Size Distribution of Powder Elastomeric Materials". Key Engineering Materials 899 (8 de septiembre de 2021): 58–66. http://dx.doi.org/10.4028/www.scientific.net/kem.899.58.

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The properties of crumb rubber (CR) of unsorted end-of-life tires and of gas masks face part crushed at ambient temperature, as well as powder elastomeric materials (PEM) obtained by high-temperature shear grinding (HTSG) of CR and high-temperature shear co-grinding of CR with thermoplastic elastomer have been investigated. The methods of dry screening with vibrating sieve, wet laser diffraction, scanning electron microscopy, determination of the specific surface area by the BET method by sorption nitrogen and powder agglomeration were used. The effect of an anti-agglomerating additive on the results of determining the particle size distribution by the methods of dry vibrating sieving and wet laser diffraction has been investigated. Methodological recommendations for determining the particle size distribution of powder elastomeric materials (PEM) obtained by the HTSG have been developed.

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Yeetsorn, Rungsima, Yaowaret Maiket y Thitinun Ungtrakul. "Experimental Study on Heat Dissipative Ability in Recycled Thermoplastic Vulcanizate and Reclaimed Rubber Composites". Key Engineering Materials 856 (agosto de 2020): 276–85. http://dx.doi.org/10.4028/www.scientific.net/kem.856.276.

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In our time with the growing cooling demand in electronics and energy industries, new thermally conductive materials are in high demand. Thermal gasket and thermal interface materials (TIM) are applications acquiring the characteristics of the thermally conductive materials. They are used to offer bonding strength and efficient heat dissipation for heat dissipating device applications. These materials are inserted between two components in order to increase the thermal coupling between them. Elastomeric materials are promising as the thermal gasket and TIM. They are, however, limited for thermal conductivity causing a thermal insulator behaviour. In this framework, the major challenge is to create suitable elastomeric composites for enhancing thermal conductivity, whereas remaining a good elastic behavior. This article presents the effects of thermally conductive fillers (aluminum nitrile and zinc oxide) on thermal properties and flexibility of recycled thermoplastic elastomer vulcanizate composites and reclaimed rubber composites, while the analysis of composite morphology is scrutinized. The objective of this research is to perceive the characteristics of recycled elastomeric composites in order to deduce a fundamental notion to develop the gaskets or TIMs from recycled materials. New flexible composites are capable to provide approximately 0.4 W/m-K of thermal conductivity. The result indicates that the composites are conceivable to be applied for thermally conductive tape or adhesive applications which required the thermal conductivity in the range of 0.4-0.5 W/m-K.

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Masoud, Ahmed I., Milena Bulic, Grace Viana y Ana K. Bedran-Russo. "Force decay and dimensional changes of thermoplastic and novel thermoset elastomeric ligatures". Angle Orthodontist 86, n.º 5 (7 de enero de 2016): 818–25. http://dx.doi.org/10.2319/082815-581.1.

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ABSTRACT Objectives: To compare over a period of 8 weeks (1) the force decay and (2) the dimensional changes between thermoplastic (TP) and thermoset (TS) elastomeric ligatures. Materials and Methods: TP and TS elastomeric ligatures were obtained from Rocky Mountain Orthodontics™. The TS ligatures were custom made specifically for this study. The sample included 72 clear TP and 72 clear TS elastomeric ligatures. The experiment was performed in a simulated oral environment (pH of 6.75) at 37°C. The remaining forces and the dimensional changes were measured at different time points over a period of 8 weeks. Results: Student’s t-tests revealed significant differences in percent force loss, percent change in outer diameter, percent change in inner diameter, and percent change in wall thickness between TP and TS elastomeric ligatures across all time points (P < .001). The difference in percent change in width between TP and TS elastomeric ligatures was not significant at all time points (P > .05). The mean difference in force loss between TP and TS across all time points was 22.91%. The TP and TS specimens exhibited 93.04% and 77.41% force loss, respectively, at the 28th day. Conclusions: This novel TS elastomeric ligature showed significantly less force decay and dimensional changes over time; therefore, it might be superior during initial leveling and aligning and during finishing stages. Using a transfer jig to prevent relaxation of the specimens before force measurement showed that force decay of commercially available elastomeric ligatures was greater than that described in previous publications.

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Miedzianowska, Justyna, Marcin Masłowski y Krzysztof Strzelec. "Thermoplastic Elastomeric Composites Filled with Lignocellulose Bioadditives. Part 1: Morphology, Processing, Thermal and Rheological Properties". Materials 13, n.º 7 (1 de abril de 2020): 1598. http://dx.doi.org/10.3390/ma13071598.

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Thermoplastic elastomer blends based on natural rubber (NR) and ethylene-vinyl acetate copolymer (EVA) with different weight ratios (30, 40, 50, 60 and 70 parts per hundred rubber (phr) of NR) and 10, 20 and 30 phr of straw were prepared and characterized. Current environmental problems were the motivation to produce this type of system, namely: the need to replace plastics at least partly with natural materials; increasing the amount of renewable raw materials and managing excess straw production. When using this bioadditive in traditional materials, the high processing temperature can be problematic, leading to the degradation of straw fibers. The solution can be polymer mixtures that are prepared at significantly lower temperatures. Scanning electron microscope (SEM) imaging was used to investigate the particle size of fibers and phase morphology of composites. Moreover, determination of the thermal properties of the filler and composites showed that the processing temperature used in the production of NR/EVA blends reduces the risk of degradation of the natural filler. Differential scanning calorimetry (DSC) was used to determine the thermal behavior of the filled composites. Finally, rheological tests of materials allow the determination of optimal processing parameters and properties of materials in dynamic conditions. The proposed blends exhibit elastic properties, and due to the lack of chemical cross-linking they can be processed and recycled like thermoplastics. In addition, they offset the disadvantages and combine the advantages of natural rubber and ethylene-vinyl acetate copolymer in the form of thermoplastic elastomeric biocomposites.

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24

Gupta, Samik, Raja Krishnamurthy, Nisha Preschilla, Amit Biswas y Anil K. Bhowmick. "Development and Properties of Novel Thermoplastic Elastomer Based on Poly (Phenylene Ether)". Rubber Chemistry and Technology 80, n.º 4 (1 de septiembre de 2007): 642–60. http://dx.doi.org/10.5254/1.3548185.

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Abstract A series of novel thermoplastic elastomers (TPEs) based on poly (phenylene ether)(PPE), which is an engineering thermoplastic with a glass transition temperature >200 °C, has been developed. The resulting blend based on PPE, Polystyrene (PS), Ethylene Vinyl Acetate (EVA) and a tri-block copolymer, Styrene-Ethylene-Butylene-Styrene (SEBS), met all the key performance criteria for thermoplastic elastomers in terms of melt processability, tensile elongation, tension set and recyclability. Depending on Flory's interaction parameter and critical surface tension value, the elastomeric components of the blends were selected. Morphological analysis of the blend using Transmission Electron Microscopy indicated a unique microstructure, wherein EVA domains were dispersed in a mainly co-continuous matrix comprising of the blend of PPE-PS/SEBS. Differential Scanning Calorimeter and Dynamic Mechanical Analysis were done to evaluate the thermal transitions of the blend and to throw light on the interactions between the various components of the blend. Thermogravimetric analysis indicated that PPE played a critical role by increasing the temperature of the onset of degradation of the blend. A comprehensive study of the structure-property correlations of this unique blend has been undertaken.

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25

Puskas, Judit E., Miroslawa El Fray, Matthew Tomkins, Lucas M. Dos Santos, Frank Fischer y Volker Altstädt. "Dynamic stress relaxation of thermoplastic elastomeric biomaterials". Polymer 50, n.º 1 (enero de 2009): 245–49. http://dx.doi.org/10.1016/j.polymer.2008.10.030.

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Bhowmick, Anil K., J. Heslop y J. R. White. "Photodegradation of thermoplastic elastomeric rubber-polyethylene blends". Journal of Applied Polymer Science 86, n.º 10 (25 de septiembre de 2002): 2393–402. http://dx.doi.org/10.1002/app.10831.

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27

Anandhan, S., P. P. De, S. K. De, Anil K. Bhowmick y S. Bandyopadhyay. "Novel Thermoplastic Elastomers Based on Acrylonitrile-Butadiene-Styrene Terpolymer (ABS) from Waste Computer Equipment and Nitrile Rubber". Rubber Chemistry and Technology 76, n.º 5 (1 de noviembre de 2003): 1145–63. http://dx.doi.org/10.5254/1.3547793.

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Abstract Acrylonitrile-butadiene-styrene terpolymer (ABS) is one of the engineering plastics most frequently used as outer casings for computer equipment such as monitors, keyboards and other similar components. In an attempt to recycle, blends of scrap computer plastics (SCP) based on ABS with nitrile rubber (NBR) were prepared and mechanical properties and morphology were studied. Effect of dynamic vulcanization on the properties of 60/40, 70/30, and 80/20 NBR/SCP blends was assessed. These blends show the thermoplastic elastomeric behavior. Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) studies show that the dynamically vulcanized NBR particles are dispersed in the ABS matrix. The thermoplastic elastomeric blends show excellent swelling resistance in IRM # 93 oil.

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28

Kántor, József, Rudolf László Farmos y Attila Levente Gergely. "Optimization of Oil Sorbent Thermoplastic Elastomer Microfiber Production by Centrifugal Spinning". Polymers 15, n.º 16 (11 de agosto de 2023): 3368. http://dx.doi.org/10.3390/polym15163368.

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Fibrous structures are promising candidates for oil–water separation applications. In this study, we have produced poly(styrene-b-isobutylene-b-styrene) thermoplastic elastomeric fibers with the centrifugal spinning fiber production method. The optimal fiber production conditions were achieved when using a 25% w/w solution concentration in an 80/20 tetrahydrofuran/toluene (w/w) solvent system at 8000 rpm rotational speed. The produced fibers were bead-free and smooth-surfaced with a diameter of 3.68 µm. The produced fibers were highly hydrophobic and oleophilic, suggested by a water contact angle of 129° and the instantaneous absorption of the oil droplet. The oil absorption study showed fast absorption kinetics with 94% relative oil uptake after 1 min and a maximum of 16.5 g sunflower oil/g fiber. The results suggest that polyisobutylene-based thermoplastic elastomers could be promising alternatives in oil absorption applications.

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29

Wojnowski, Jacek y Jarosław Chmiel. "Personalized Anti-Vibration Protection for Telematics Devices in Urban Freight Transport Vehicles". Energies 14, n.º 14 (11 de julio de 2021): 4193. http://dx.doi.org/10.3390/en14144193.

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Vibrations are a major cause of human health disorders, circuit boards and machinery damage. Vibration dampers are considered to be the best option to counter these issues. Three-dimensional printing techniques play an increasingly important role in manufacturing small polymer parts with tailored properties. Thermoplastic elastomers (TPE) constitute a perfect material for manufacturing small-scale series absorber prototypes due to their thermoplastic nature, good elasticity and damping properties. This paper proposes a novel multi-level approach to the design and manufacturing process, e.g., the first level—selection of material; second level—decision about the geometry of a damper; third—selection of technological printing parameters; fourth—post-printing treatment. This work primarily aims to overview the design and manufacturing process levels. The impact of each step on the damping capacity of small absorbers is assessed. It was found that thermoplastic elastomers and fused deposition modeling (FDM) have huge potential in shaping the physical properties of small, elastomeric absorbers. It was assessed that at every step of the multilevel design and manufacturing process (MDMP), the designer could tailor the damping to meet the desired criteria of a final product: a cylinder-shaped hollow damper that can be made from TPE polymer without post-printing treatment and is characterized by good damping.

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30

Rodríguez-Sánchez, Alejandro E., Sergio Ledesma, Agustín Vidal-Lesso y Elías Ledesma-Orozco. "The use of neural networks and nonlinear finite element models to simulate the temperature-dependent stress response of thermoplastic elastomers". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, n.º 3 (5 de diciembre de 2019): 425–37. http://dx.doi.org/10.1177/1464420719890890.

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In this study, a methodology that combines artificial neural networks and nonlinear hyperelastic finite element modeling to simulate the temperature-dependent stress response of elastomer solids is presented. The methodology is verified by a discrete model of a tensile test specimen, which is used to generate stress–strain pairs of existent experimental data. The proposed method is also tested with a benchmark problem of a rubber-like cylinder under compression. Three grades of an elastomer used for diverse engineering applications are used throughout the study. On this basis, three neural network architecture with 10 hidden neurons are implemented as constitutive models to reproduce the experimental data of the materials. The validation results show that the proposed methodology can reproduce tensile tests with an error of 5% of less than regarding experimental data for elastomers that present no yielding point. The benchmark problem results were at the range expected for the elastomer materials with no yielding, where it was possible to derive force temperature-dependent responses. These results suggest that the methodology helps the prediction of the material response when only material stress–strain curves at different temperatures exist. Therefore, the presented approach in this contribution helps to simulate the temperature-dependent stress responses of elastomeric solids with no defined yielding point.

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31

Kunanusont, Nappaphan, Chavakorn Samthong, Fan Bowen, Masayuki Yamaguchi y Anongnat Somwangthanaroj. "Effect of Mixing Method on Properties of Ethylene Vinyl Acetate Copolymer/Natural Rubber Thermoplastic Vulcanizates". Polymers 12, n.º 8 (4 de agosto de 2020): 1739. http://dx.doi.org/10.3390/polym12081739.

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Thermoplastic vulcanizate (TPV) has excellent elastomeric properties and can be reprocessed multiple times. TPV is typically produced by using the dynamic vulcanization (DV) method in which rubber is crosslinked simultaneously with thermoplastics. Peroxide-crosslinked TPV can increase the compatibility between rubber and thermoplastics but loses its reprocessability due to excess crosslinking in the latter. In this work, we overcome this obstacle by using a two-step mixing method to prepare fully crosslinked elastomers of ethylene vinyl acetate copolymer (EVA) and natural rubber (NR). Each sample formulation was prepared with three different mixing methods for comparison: NR-DV, Split-DV, and All-DV. For NR-DV, NR was crosslinked prior to the addition of EVA together with the thermal stabilizer (TS). For Split-DV, a small amount of EVA and NR was crosslinked prior to the addition of EVA and TS. In the All-DV method, EVA and NR were crosslinked, and then TS was added. The appearance and processability of the samples were affected by the degree of crosslinking. NR-DV showed a non-homogeneous texture. Although the samples of the All-DV method appeared homogeneous, their mechanical and rheological properties were inferior to those of the Split-DV method. The mechanical properties of the Split-DV samples were not significantly changed after reprocessing 10 times. Therefore, Split-DV is the preferred method for TPV production.

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32

Costa, Lucas Barros da, Renata Nunes Oliveira y Alex da Silva Sirqueira. "Green thermoplastic vulcanized based on recycled polyethylene and waste tire powder". Research, Society and Development 11, n.º 4 (24 de marzo de 2022): e50011427421. http://dx.doi.org/10.33448/rsd-v11i4.27421.

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ThermoPlastic Vulcanized (TPV) is a class of polymeric materials capable of combining the high elasticity of elastomers with the recycling of thermoplastics. The production of TPV with recycled material contributes to the reduction of polymeric waste on the planet, reducing its environmental impact. In this study, recycled TPV samples were produced by combining recycled polyethylene and waste tire powder. The TPV samples were obtained in an internal mixer, changing the processing conditions, during the vulcanization and stabilization stages of the final torque. The results showed that by reducing the processing speed from 60 to 40 rpm, TPV samples were obtained with higher tensile strength and low swelling in oil. ANOVA statistical analysis confirmed that significant changes occurred due to processing speed variations. The DUNCAN mean parity statistical model was used for comparisons between pairs of TPV samples. Frequency sweeping rheological analysis confirmed the effect of adding tire powder on the samples’ elastic modulus. There were no changes in the viscous and elastic modules of the samples. The absence of significant changes in the final morphology of the TPV samples was attributed to the tire powder size. The increased properties of TPV samples are attributed to new crosslinking of the elastomeric phase during dynamic vulcanization.

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Sundermann, Lion, Sebastian Leineweber, Benjamin Klie, Heike Wittek, Thomas Ebel, Birger Reitz, Kathrin Ottink et al. "Tailoring the Curing Kinetics of NBR-Based Rubber Compounds for Additive Manufacturing of Rod Seals". Advances in Polymer Technology 2023 (22 de agosto de 2023): 1–16. http://dx.doi.org/10.1155/2023/7343194.

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The additive manufacturing (AM) of elastomeric parts based on high-viscosity reinforced rubbers has increasingly become a topic of scientific research in recent years. In addition to the viscosity, which is several decades higher during processing than the viscosities of thermoplastics, the flowability of the compound after the printing process and the necessary chemical crosslinking of the printed component play a decisive role in producing an elastic, high-quality, and geometrically stable part. After the first technological achievements using the so-called additive manufacturing of elastomers (AME) process, the knowledge gained has to be transferred first to concrete industrial parts. Therefore, in this study, the cure kinetics of a conventional rubber compound are tailored to match the specific requirements for scorch safety in the additive manufacturing of an industrial 2-component rod seal based on an acrylonitrile butadiene rubber O-ring in combination with a thermoplastic polyurethane as the base body. Experimental tests on a test rig for rod seals demonstrate the functionality of this additively manufactured 2-component rod seal.

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Li, Haixia, Wei Wei y Huiming Xiong. "Metallo-supramolecular complexes mediated thermoplastic elastomeric block copolymer". Polymer 55, n.º 22 (octubre de 2014): 5739–45. http://dx.doi.org/10.1016/j.polymer.2014.09.032.

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Ghosh, Tuhin y Niranjan Karak. "Silicone-Containing Biodegradable Smart Elastomeric Thermoplastic Hyperbranched Polyurethane". ACS Omega 3, n.º 6 (25 de junio de 2018): 6849–59. http://dx.doi.org/10.1021/acsomega.8b00734.

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36

Choudhury, Namita Roy y Anil K. Bhowmick. "Ageing of natural rubber-polyethylene thermoplastic elastomeric composites". Polymer Degradation and Stability 25, n.º 1 (enero de 1989): 39–47. http://dx.doi.org/10.1016/0141-3910(89)90122-5.

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37

Chan, Wei Xuan, Sum Huan Ng, King Ho Holden Li, Woo-Tae Park y Yong-Jin Yoon. "Micro-ultrasonic welding using thermoplastic-elastomeric composite film". Journal of Materials Processing Technology 236 (octubre de 2016): 183–88. http://dx.doi.org/10.1016/j.jmatprotec.2016.05.025.

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38

Naskar, Amit K., Anil K. Bhowmick y S. K. De. "Thermoplastic elastomeric composition based on ground rubber tire". Polymer Engineering & Science 41, n.º 6 (junio de 2001): 1087–98. http://dx.doi.org/10.1002/pen.10809.

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39

De Sarkar, Mousumi, Prajna P. De y Anil K. Bhowmick. "Thermoplastic elastomeric hydrogenated styrene-butadiene elastomer: Optimization of reaction conditions, thermodynamics, and kinetics". Journal of Applied Polymer Science 66, n.º 6 (7 de noviembre de 1997): 1151–62. http://dx.doi.org/10.1002/(sici)1097-4628(19971107)66:6<1151::aid-app15>3.0.co;2-4.

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40

Hel, Cindy Le, Véronique Bounor-Legaré, Mathilde Catherin, Antoine Lucas, Anthony Thèvenon y Philippe Cassagnau. "TPV: A New Insight on the Rubber Morphology and Mechanic/Elastic Properties". Polymers 12, n.º 10 (10 de octubre de 2020): 2315. http://dx.doi.org/10.3390/polym12102315.

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The objective of this work is to study the influence of the ratio between the elastomer (EPDM) phase and the thermoplastic phase (PP) in thermoplastic vulcanizates (TPVs) as well as the associated morphology of the compression set of the material. First, from a study of the literature, it is concluded that the rubber phase must be dispersed with a large distribution of the domain size in the thermoplastic phase in order to achieve a high concentration, i.e., a maximal packing fraction close to ~0.80. From this discussion, it is inferred that a certain degree of progress in the crosslinking reaction must be reached when the thermoplastic phase is melted during mixing in order to achieve dispersion of the elastomeric phase in the thermoplastic matrix under maximum stress. In terms of elasticity recovery which is measured from the compression set experiment, it is observed that the crosslinking agent nature (DCP or phenolic resin) has no influence in the case of a TPV compared with a pure crosslinked EPDM system. Then, the TPV morphology and the rubber phase concentration are the first order parameters in the compression set of TPVs. Finally, the addition of carbon black fillers leads to an improvement of the mechanical properties at break for the low PP concentration (20%). However, the localization of carbon black depends on the crosslinking chemistry nature. With radical chemistry by organic peroxide decomposition, carbon black is located at the interface of EPDM and PP acting as a compatibilizer.

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41

Emminger, Carina, Umut D. Çakmak, Rene Preuer, Ingrid Graz y Zoltán Major. "Hyperelastic Material Parameter Determination and Numerical Study of TPU and PDMS Dampers". Materials 14, n.º 24 (11 de diciembre de 2021): 7639. http://dx.doi.org/10.3390/ma14247639.

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Dampers provide safety by controlling unwanted motion that is caused due to the conversion of mechanical work into another form of energy (e.g., heat). State-of-the-art materials are elastomers and include thermoplastic elastomers. For the polymer-appropriate replacement of multi-component shock absorbers comprising mounts, rods, hydraulic fluids, pneumatic devices, or electro-magnetic devices, among others, in-depth insights into the mechanical characteristics of damper materials are required. The ultimate objective is to reduce complexity by utilizing inherent material damping rather than structural (multi-component) damping properties. The objective of this work was to compare the damping behavior of different elastomeric materials including thermoplastic poly(urethane) (TPU) and silicone rubber blends (mixtures of different poly(dimethylsiloxane) (PDMS)). Therefore, the materials were hyper- and viscoelastic characterized, a finite element calculation of a ball drop test was performed, and for validation, the rebound resilience was measured experimentally. The results revealed that the material parameter determination methodology is reliable, and the data that were applied for simulation led to realistic predictions. Interestingly, the rebound resilience of the mixture of soft and hard PDMS (50:50) wt% was the highest, and the lowest values were measured for TPU.

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42

Utrera-Barrios, Saul, Ornella Ricciardi, Sergio González, Raquel Verdejo, Miguel Ángel López-Manchado y Marianella Hernández Santana. "Development of Sustainable, Mechanically Strong, and Self-Healing Bio-Thermoplastic Elastomers Reinforced with Alginates". Polymers 14, n.º 21 (30 de octubre de 2022): 4607. http://dx.doi.org/10.3390/polym14214607.

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New bio-thermoplastic elastomer composites with self-healing capacities based on epoxidized natural rubber and polycaprolactone blends reinforced with alginates were developed. This group of salts act as natural reinforcing fillers, increasing the tensile strength of the unfilled rubber from 5.6 MPa to 11.5 MPa without affecting the elongation at break (~1000% strain). In addition, the presence of ionic interactions and hydrogen bonds between the components provides the material with a thermally assisted self-healing capacity, as it is able to restore its catastrophic damages and recover diverse mechanical properties up to ~100%. With the results of this research, an important and definitive step is planned toward the circularity of elastomeric materials.

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Armstrong, Daniel P. y Richard J. Spontak. "DESIGNING DIELECTRIC ELASTOMERS OVER MULTIPLE LENGTH SCALES FOR 21ST CENTURY SOFT MATERIALS TECHNOLOGIES". Rubber Chemistry and Technology 90, n.º 2 (1 de junio de 2017): 207–24. http://dx.doi.org/10.5254/rct.17.82660.

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ABSTRACT Dielectric elastomers (DEs) constitute an increasingly important category of electroactive polymers. They are in a class of generally soft materials that, upon exposure to an electric stimulus, respond by changing size, shape, or both. Derived from network-forming macromolecules, DEs are lightweight, robust and scalable, and they are capable of exhibiting giant electroactuation strains, high electromechanical efficiencies, and relatively low strain-cycling hysteresis over a broad range of electric fields. Due primarily to their attractive electromechanical attributes, DEs are of growing interest in diverse biomedical, (micro)robotic, and analytical technologies. Since the seminal studies of these electroresponsive materials (initially fabricated mainly from chemically cross-linked acrylic and silicone elastomers), advances in materials design over multiple length scales have resulted in not only improved electromechanical performance but also better mechanistic understanding. We first review the fundamental operating principles of DEs developed from conventional elastomers that undergo isotropic electroactuation and then consider more recent advances at different length scales. At the macroscale, incorporation of oriented fibers within elastomeric matrices is found to have a profound impact on electroactuation by promoting an anisotropic response. At the mesoscale, physically cross-linked thermoplastic elastomer gel networks formed by midblock-swollen triblock copolymers provide a highly tunable alternative to chemically cross-linked elastomers. At the nanoscale, the chemical synthesis of binetwork and bottlebrush elastomers permits extraordinarily enhanced electromechanical performance through targeted integration of inherently prestrained macromolecular networks.

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44

Shahbikian, Shant, Pierre J. Carreau, M.-C. Heuzey, Maria D. Ellul, Hari P. Nadella, John Cheng y Pradeep Shirodkar. "MORPHOLOGY AND RHEOLOGY OF NONREACTIVE AND REACTIVE EPDM/PP BLENDS IN TRANSIENT SHEAR FLOW: PLASTICIZED VERSUS NONPLASTICIZED BLENDS". Rubber Chemistry and Technology 84, n.º 3 (1 de septiembre de 2011): 325–53. http://dx.doi.org/10.5254/1.3570529.

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Abstract Both nonplasticized and plasticized ethylene-propylene-diene-terpolymer/polypropylene (EPDM/PP) based thermoplastic elastomers (TPEs) were prepared in the presence and absence of a curing system (i.e., reactive vs nonreactive TPEs). The nonlinear viscoelastic behavior and morphology evolution of these blends were investigated through single and multiple start-up transient experiments to find out the effects of composition, plasticizer, and the presence of the curing system in a homogeneous shear flow field. Due to the highly elastic nature of the elastomeric component, the shear rate was set to 0.1 s−1 and in the case of multiple start-up experiments a 10 min rest time was set between consecutive shearing cycles. The specific interfacial area (Q) of the TPEs was analyzed prior and after shearing and subsequently correlated to the corresponding rheological response of these blends. The magnitude and the width of the stress overshoot were correlated to the morphology of the blends, elastomer content, the presence of plasticizer and curing system. The presence of a plasticizer (paraffinic oil) drastically decreased the viscosity and elasticity of both neat polymers and consequently the resulting TPEs; and it further reduced the initial curing rate of the elastomeric component at the early shearing stage of the reactive TPEs. Moreover, the plasticization promoted swelling and coalescence, enlarging the size of the polymeric domains, and decreasing the specific interfacial area. Furthermore, the in situ curing reaction in the reactive TPE blends resulted in less elongated polymeric domains with an irregular and larger interface compared to the nonreactive blends. A phase inverted morphology has also been observed for nonplasticized high elastomer content reactive TPEs sheared for long periods. The obtained experimental morphology data of the nonreactive blends subjected to multiple start-up experiments was fairly well predicted using a phenomenological model proposed by Lee and Park [J. Rheo. 38(5), 1994].

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45

Le, H. H., M. Tiwari, S. Ilisch y H. J. Radusch. "Elastomeric and electrically conductive materials on basis of thermoplastic elastomers and their controlled manufacturing". Plastics, Rubber and Composites 35, n.º 10 (diciembre de 2006): 410–17. http://dx.doi.org/10.1179/174328906x149691.

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Abbasov, A. M., L. M. Abbasova y Ya M. Bilalov. "Structure and Properties of Polyolefin-Based Thermoplastic Elastomeric Materials". International Polymer Science and Technology 33, n.º 9 (septiembre de 2006): 61–64. http://dx.doi.org/10.1177/0307174x0603300914.

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Vijayakumar, PC, R. Jeevan Kumar, Anish Johns, N. Sathyan y Jobish Johns. "Solvent Transport Properties of Er/Ps Thermoplastic Elastomeric Blends". Progress in Rubber Plastics and Recycling Technology 31, n.º 1 (febrero de 2015): 55–67. http://dx.doi.org/10.1177/147776061503100104.

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48

Roy Choudhury, Namita, T. K. Chaki y Anil K. Bhowmick. "Thermal characterization of thermoplastic elastomeric natural rubber-polypropylene blends". Thermochimica Acta 176 (marzo de 1991): 149–61. http://dx.doi.org/10.1016/0040-6031(91)80270-s.

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Masciullo, Cecilia, Agnese Sonato, Filippo Romanato y Marco Cecchini. "Perfluoropolyether (PFPE) Intermediate Molds for High-Resolution Thermal Nanoimprint Lithography". Nanomaterials 8, n.º 8 (10 de agosto de 2018): 609. http://dx.doi.org/10.3390/nano8080609.

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Among soft lithography techniques, Thermal Nanoimprint Lithography (NIL) is a high-throughput and low-cost process that can be applied to a broad range of thermoplastic materials. By simply applying the appropriate pressure and temperature combination, it is possible to transfer a pattern from a mold surface to the chosen material. Usually, high-resolution and large-area NIL molds are difficult to fabricate and expensive. Furthermore, they are typically made of silicon or other hard materials such as nickel or quartz for preserving their functionality. Nonetheless, after a large number of imprinting cycles, they undergo degradation and become unusable. In this paper, we introduce and characterize an innovative two-step NIL process based on the use of a perfluoropolyether (PFPE) intermediate mold to replicate sub-100 nm features from a silicon mold to the final thermoplastic material. We compare PFPE elastomeric molds with molds made of the standard polydimethylsiloxane (PDMS) elastomer, which demonstrates better resolution and fidelity of the replica process. By using PFPE intermediate molds, the nanostructured masters are preserved and the throughput of the process is significantly enhanced.

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50

Banerjee, Shib, Stephen Burbine, Nischay Kodihalli Shivaprakash y Joey Mead. "3D-Printable PP/SEBS Thermoplastic Elastomeric Blends: Preparation and Properties". Polymers 11, n.º 2 (17 de febrero de 2019): 347. http://dx.doi.org/10.3390/polym11020347.

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Currently, material extrusion 3D printing (ME3DP) based on fused deposition modeling (FDM) is considered a highly adaptable and efficient additive manufacturing technique to develop components with complex geometries using computer-aided design. While the 3D printing process for a number of thermoplastic materials using FDM technology has been well demonstrated, there still exists a significant challenge to develop new polymeric materials compatible with ME3DP. The present work reports the development of ME3DP compatible thermoplastic elastomeric (TPE) materials from polypropylene (PP) and styrene-(ethylene-butylene)-styrene (SEBS) block copolymers using a straightforward blending approach, which enables the creation of tailorable materials. Properties of the 3D printed TPEs were compared with traditional injection molded samples. The tensile strength and Young’s modulus of the 3D printed sample were lower than the injection molded samples. However, no significant differences could be found in the melt rheological properties at higher frequency ranges or in the dynamic mechanical behavior. The phase morphologies of the 3D printed and injection molded TPEs were correlated with their respective properties. Reinforcing carbon black was used to increase the mechanical performance of the 3D printed TPE, and the balancing of thermoplastic elastomeric and mechanical properties were achieved at a lower carbon black loading. The preferential location of carbon black in the blend phases was theoretically predicted from wetting parameters. This study was made in order to get an insight to the relationship between morphology and properties of the ME3DP compatible PP/SEBS blends.

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