Nonpolar Elastomers Research Articles

Epoxy modified styrene butadiene rubber (SBR) in green tire application

Styrene butadiene rubber (SBR) is an important elastomer in tire application. The tire industries are facing challenges in optimizing the magic triangle, which balances three contradicting properties: abrasion resistance, wet traction, and rolling resistance (RR). There are numerous approaches foroptimizingtire compound characteristics, which eventually impact tire performance. Choosing an appropriate kind of reinforcing filler is one of the techniques that may be used. Silica based tires give better traction properties and low rolling resistance, but silica has hydroxyl groups on the surface, and it is not compatible with non-polar elastomers such as Emulsion-based Styrene Butadiene Rubber (ESBR). Hence, it is necessary to incorporate some polar moieties into ESBR chains to enhance the compatibility with silica. In this study, non-polar Emulsion-based Styrene Butadiene Rubber (ESBR) is transformed into polar ESBR by modifying with epoxidizing reagent at room temperature. The epoxidized-ESBR (E-ESBR) was characterized by 1H NMR, FT-IR, and DSC analyses. Synthesized E-ESBR was compounded with ESBR and silica filler for the ‘green tire’ tread compounding (ESBR-Silica/E-ESBR). The incorporation of E-ESBR improved silica dispersion in the ESBR matrix. Hence, the tensile strength of ESBR-Silica/E-ESBR compound improved. The rolling resistance decreased compared to the ESBR-Silica compound. Furthermore, dry, wet, and snow traction properties of the compounded system were improved by 9 %, 25 %, and 37 %, respectively, in comparison to the pristine EBSR-Silica compound. Thus, the incorporation of the E-ESBR system could generate a new pave for better dispersion of silica in the non-polar elastomer matrix.

Improving performance of natural rubber composites by the application of functional biofiller: horsetail modified with silane coupling agents

The growing ecological awareness of society and increasingly stringent legal requirements regarding environmental protection and the strategy of implementing the principles of sustainable development force the search for and continuous development of environmentally friendly solutions in the field of polymer materials technology. One of the directions is the use of raw materials from renewable sources. For this reason, the research object of the presented work was natural rubber composites containing a filler of plant origin in the form of ground horsetail (HT) biomass. Despite its health-promoting properties, it is commonly considered a weed. What’s more, the ubiquitous occurrence and surplus make it a valuable source of waste biomass for management. Taking into account the limitations resulting from the hydrophilic nature of the lignocellulosic filler, and the related poor adhesion to the non-polar elastomer matrix, the horsetail filler was modified with organoalkoxysilanes. The study used silane compounds containing groups that can affect the properties of vulcanizates in various ways, such as vinyltriethoxysilane (VTES), 3,3′-Tetrathiobis(propyl-triethoxysilane) (TESPTS), 3-(aminopropyl)triethoxysilane (APTES), 3-(chloropropyl)triethoxysilane (CPTES) and octyltriethoxysilane (OTES). The biomass in the form of field horsetail was previously modified with selected silanes. Then, the bioadditive prepared in this way was applied to rubber mixtures. The process of modifying the natural filler contributed to structural changes in the lignocellulosic material, which may indicate the effective attachment of silane compounds to the horsetail surface. The results of the contact angle analysis show that the treatment strongly influenced the surface characteristics of the fillers, making them more hydrophobic. The results show that the type of silane coupling agent affects not only the processing associated with the vulcanization process but also the mechanical properties of the NR vulcanizates. This phenomenon is probably the result of increased rubber-bioadditive interaction and improved filler dispersion. Moreover, all composites with modified HT, show a greater flame permanence time than the one using unmodified filler.Graphical abstract

Intrinsically stretchable three primary light-emitting films enabled by elastomer blend for polymer light-emitting diodes.

Intrinsically stretchable light-emitting materials are crucial for skin-like wearable displays; however, their color range has been limited to green-like yellow lights owing to the restricted stretchable light-emitting materials (super yellow series materials). To develop skin-like full-color displays, three intrinsically stretchable primary light-emitting materials [red, green, and blue (RGB)] are essential. In this study, we report three highly stretchable primary light-emitting films made from a polymer blend of conventional RGB light-emitting polymers and a nonpolar elastomer. The blend films consist of multidimensional nanodomains of light-emitting polymers that are interconnected in an elastomer matrix for efficient light-emitting under strain. The RGB blend films exhibited over 1000 cd/m2 luminance with low turn-on voltage (<5 Von) and the selectively stretched blend films on rigid substrate maintained stable light-emitting performance up to 100% strain even after 1000 multiple stretching cycles.

On the prospects for the use of polymeric materials for sorbents intended for water purification from oil products

Environmental safety occupies a major place in the extraction of minerals such as crude oil. The optimal outcome in the event of emergency situations during the production and spill of hydrocarbons is the use of mechanical frequent discharge using special sorbents. The evolution of oil-sorbing materials today does not have such filtration. Conventionally, they can be divided into inorganic, natural and synthetic. Efficiency depends on the use of oil-absorbing capacity, variety of applications, hydrophobicity and oleophilicity, as well as mandatory toxicity during operation. Modern technologies create sorbents based on foamed polymeric materials capable of pumping tons of oil by weight of 1 kg. Over the past 10 years, the authors have devoted to research to the modification of foamed polymeric materials to create superhydrophobic/superolefin sorbents. However, many works did not go beyond the laboratory, due to the complexity and high cost of the product. The purpose of this article is to identify the most promising polymeric materials with effective classes of oil-sorbing properties. A comparative analysis is presented in the paper justifying the choice of the quality of oil-absorbing foam material of non-polar polymers. Due to the natural hydrophobicity and oleophilicity, elasticity, availability of Russian offers on the market, there are opportunities for the development of this direction. The properties not explored of foamed polymeric materials based on ethylene-propylene-diene rubbers, which, among other things, have weather resistance, a wide temperature range of application, which is important for operation in the Far North or equatorial seas, where many other polymers lose their ability to effectively collect spills, high ability to fill up in the production of the mixture, which allows modifying the composition. A well-studied technology for foaming open-сell polymeric materials based on non-polar elastomers is added to the positive facts.

Super-Tough Poly(lactic Acid)-Based Thermoplastic Vulcanizate Based on Selective Dispersion and In Situ Compatibilization of Commercial Reinforcing Fillers and Its Application in Three-Dimensional Printing

Blending with elastomers is a commonly used method to improve the toughness of poly(lactic acid) (PLA). However, the poor compatibility between polar PLA and the nonpolar elastomer results in a limited improvement of the toughness. In this work, we report a simple but effective strategy to improve the compatibility between PLA and natural rubber (NR) and manufacture super-tough PLA-based thermoplastic vulcanizate (TPV). We choose the widely used reinforcing filler SiO2 nanoparticles as the compatibilizer, whose modification using 3-(trimethoxysilyl)propyl methacrylate (KH570) is synchronized with the dynamic vulcanization. Simultaneously, the modified SiO2 nanoparticles migrate from the NR phase to the PLA/NR interface due to the interfacial tension. The modified SiO2 nanoparticles located at the interface entangle with the NR chains on the one hand and graft with the PLA chain on the other hand, acting as a “bridge” to improve the interfacial compatibility of the two phases. While only adding a small amount of filler, 20 phr SiO2 nanoparticles in NR and 7 phr modifier in SiO2, the impact strength of the PLA/NR (80/20) TPV increases to 95.96 kJ/m2 (without fracture), which is 38-fold than pure PLA. Even in a low temperature of −30 °C, the impact strength is still 7.93 kJ/m2. Finally, the co-continuous structure and the excellent toughness with a small amount of toughener make the TPV have great potential for application in the 3D printing field (processing speed of 110 m/min, over 100 times bend after immersion in hot water).

Systematic Literature Review of the Effect of Layered Double Hydroxides on the Mechanical Properties of Rubber.

Layered double hydroxides (LDHs) have attracted interest as reinforcing fillers in elastomers due to their ease of synthesis and customisability. A systematic review was performed on the effect of LDHs on the mechanical properties of elastomers using the Scopus database. Of the 61 articles relevant to the search criteria, the majority were published on polyurethane (PU) and nitrile butadiene rubber (NBR). Mg-Al LDH was used in most of the studies and Zn-Al LDH was used second most common. LDH can act as a reinforcing filler, typically increasing tensile strength even at low concentrations, so it could be used as an alternative to traditional reinforcing fillers for elastomers. LDH can also be made a functional filler by selecting the right metals and interlayer anions. It was found that Mg-Al LDH and Zn-Al LDH can both participate in crosslinking reactions and can replace MgO and ZnO, respectively. Less Zn ions are required for crosslinking when LDH is used than when ZnO is used, making LDH more environmentally friendly. Organic modification is usually required to improve compatibility with the elastomer matrix, especially in non-polar elastomers. It enables exfoliation of the LDH and intercalation of polymer chains into the LDH interlayer to occur. Organic modifiers can also be used to functionalise the LDH. Stearic acid used in crosslinking systems can be replaced by stearate anions from stearate-modified LDH.

Optimization of hybrid oil/water‐swelling ethylene/propylene/diene monomer compounds

AbstractHybrid swell packers are rubber products capable of swelling in (saline) water and hydrocarbon oils, by exploiting the hydrocarbon diffusion properties of an nonpolar elastomer with the osmotic swelling of a water absorbent (WA). In this study, a variety of modified natural and synthetic WAs and mixtures thereof have been screened in a rubber compound with respect to swelling in decalin, demineralized, and saline water, respectively. We aimed at achieving high and fast swelling in all used media. Mixing of the various WAs in an ethylene/propylene/diene monomer (EPDM)/carbon black masterbatch at an addition level of 75 phr did not pose any problems, although it was found that the WAs did affect the sulfur vulcanization. Decalin swelling of the vulcanizates is very fast, reaching high equilibrium swelling within 1.5 days. Swelling in demineralized or saline water is much slower, with up to 300% swelling in water and up to 100% swelling in saline water. Significant leaching of the organic WA from the EPDM vulcanizates to the water phase occurs. Some combinations of WAs show synergetic effects for swelling in water. To our knowledge, such a systematic study of hybrid swelling elastomers constitutes a novelty in the open literature.

Construction of a Dual Ionic Network in Natural Rubber with High Self-Healing Efficiency through Anionic Mechanism

Even though considerable efforts have been applied toward self-healing materials, construction of a reversible network in a nonpolar elastomer with a high strength and self-healing behavior is stil...

LIGHTWEIGHT ELASTOMER COMPOUNDS REINFORCED WITH CELLULOSE NANOFIBRILS AND A CARBON BLACK HYBRID FILLER SYSTEM

ABSTRACT Cellulose is found in the walls of plant cells, making it the most common biopolymer in the world. It is mechanically stable, resistant to hydrolysis, and boasts—especially in its nanoscopic state—a large reactive surface area and low density. To realize reinforcement in rubbers, the large and polar cellulose surface must interact with the nonpolar elastomer matrix. The dispersion of hydrophilic fillers is, however, still a major challenge in rubber technology. In this work, commercially available nanofibrillated cellulose (NFC) was incorporated into a nonpolar BIIR via latex mixing. Transmission electron microscopy, tensile testing, swelling, and rheometry were used to characterize the compound properties and the reinforcing potential of NFC. The compounds were compared with the established and highly dispersible standard carbon black N550 with a medium specific surface area. In addition, hybrid filler systems with both particle types were prepared. This yielded well-dispersed nanocomposites of a new kind exhibiting high stiffness, good tensile properties, and reduced material weight.

Intrinsically Stretchable Organic-Tribotronic-Transistor for Tactile Sensing.

Stretchable electronics are of great significance for the development of the next-generation smart interactive systems. Here, we propose an intrinsically stretchable organic tribotronic transistor (SOTT) without a top gate electrode, which is composed of a stretchable substrate, silver nanowire electrodes, semiconductor blends, and a nonpolar elastomer dielectric. The drain-source current of the SOTT can be modulated by external contact electrification with the dielectric layer. Under 0-50% stretching both parallel and perpendicular to the channel directions, the SOTT retains great output performance. After being stretched to 50% for thousands of cycles, the SOTT can survive with excellent stability. Moreover, the SOTT can be conformably attached to the human hand, which can be used for tactile signal perception in human-machine interaction and for controlling smart home devices and robots. This work has realized a stretchable tribotronic transistor as the tactile sensor for smart interaction, which has extended the application of tribotronics in the human-machine interface, wearable electronics, and robotics.

Elastomer Reinforced with Innate Sulfur-Based Cross-Links as Ligands.

Although the incorporation of sacrificial bonds into an elastomer is an effective way to provide a combination of high strength and high fracture toughness, this method normally involves complicated chemical processes. The coordination between metal ions and polysulfides has been documented. However, the potential of polysulfide structures in vulcanizates as ligands has long been neglected. Using innate sulfur-based cross-links, we show how weak and nonpolar elastomers achieve significant reinforcement without modification of the backbone. By simply soaking vulcanizates into solutions containing metal ions, dual ions are simultaneously introduced into the vulcanizate to generate coordinations with different bond strengths, resulting in an unprecedented high modulus. Overall, this work presents a universal yet high-efficiency reinforcing strategy to prepare high-performance elastomers without additional chemical modifications, which should promote comprehensive research and industrial application of sacrificial bond strategies for elastomers.

Buildup of Multi-Ionic Supramolecular Network Facilitated by In-Situ Intercalated Organic Montmorillonite in 1,2-Polybutadiene.

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions.

Intrinsically Tuning the Electromechanical Properties of Elastomeric Dielectrics: A Chemistry Perspective.

Dielectric elastomers have the capability to be used as transducers for actuation and energy harvesting applications due to their excellent combination of large strain capability (100-400%), rapid response (10-3 s), high energy density (10-150kJm-3 ), low noise, and lightweight nature. However, the dielectric properties of non-polar elastomers such as dielectric permittivity εr , breakdown strength Eb , and dielectric loss ε ″, need to be enhanced for real world applications. The introduction of polar groups or structures into dielectric elastomers through covalently bonding is an attractive approach to 'intrinsically' induce a permanent polarity to the elastomers, and can eliminate the poor post-processing issues and breakdown strength of extrinsically modified materials, which have often been prepared by incorporation of fillers. This review discusses the chemical methods for modification of dielectric elastomers, such as hydrosilylation, thiol-ene click chemistry, azide click chemistry, and atom transfer radical polymerization. The effects of the type and concentration of polar groups on the dielectric and mechanical properties of the elastomers and their performance in actuation and harvesting systems are discussed. State-of-the-art developments and perspectives of modified dielectric elastomers for deformable energy generators and transducers are provided.

ISOBUTYLENE-RICH IMIDAZOLIUM IONOMERS: INFLUENCE OF ION-PAIR DISTRIBUTION AND COUNTER-ANION STRUCTURE

ABSTRACT New chemistry for overcoming the limitations of nonpolar elastomers is detailed, with particular emphasis on improving interfacial adhesion and the intensity of polymer–filler interactions. The chemical modification of brominated poly(isobutylene-co-isoprene) and brominated poly(isobutylene-co-para-methyl styrene) is used to introduce small amounts of imidazolium bromide functionality. Unlike conventional isobutylene-rich elastomers, ionomer derivatives bearing vinylimidazolium bromide groups are peroxide curable. The ultimate cross-link density, along with accompanying thermoset properties, can be tailored by changing the amount and distribution of N-vinylimidazolium and N-butylimidazolium functionality. Moreover, the counteranion can be exchanged from bromide to sulfonate or vinylsulfonate to further optimize adhesive, tensile, and stress relaxation properties. Bromide exchange anionic montmorillonite clay platelets can yield thermoset ionomer nanocomposites with a high degree of reinforcement despite a relatively low filler loading.

Investigating Limiting Factors in Stretchable All-Carbon Transistors for Reliable Stretchable Electronics.

Stretchable form factors enable electronic devices to conform to irregular 3D structures, including soft and moving entities. Intrinsically stretchable devices have potential advantages of high surface coverage of active devices, improved durability, and reduced processing costs. This work describes intrinsically stretchable transistors composed of single-walled carbon nanotube (SWNT) electrodes and semiconductors and a dielectric that consists of a nonpolar elastomer. The use of a nonpolar elastomer dielectric enabled hysteresis-free device characteristics. Compared to devices on SiO2 dielectrics, stretchable devices with nonpolar dielectrics showed lower mobility in ambient conditions because of the absence of doping from water. The effect of a SWNT band gap on device characteristics was investigated by using different SWNT sources as the semiconductor. Large-band-gap SWNTs exhibited trap-limited behavior caused by the low capacitance of the dielectric. In contrast, high-current devices based on SWNTs with smaller band gaps were more limited by contact resistance. Of the tested SWNT sources, SWNTs with a maximum diameter of 1.5 nm performed the best, with a mobility of 15.4 cm2/Vs and an on/off ratio >103 for stretchable transistors. Large-band-gap devices showed increased sensitivity to strain because of a pronounced dependence on the dielectric thickness, whereas contact-limited devices showed substantially less strain dependence.

The Influence of the Polymeric Compatibiliser on the Impact Strength and Physicomechanical Properties of PP/NBR Composites Produced by Reactive Extrusion using a Peroxide Modifying System

In order to improve the balance of flow, impact strength, and physicomechanical properties of polypropylene/nitrile butadiene rubber composites of structural designation, we investigated the possibility of using two complementary approaches in the process of manufacturing the composites. Firstly, this involves the introduction into the composition of these composites of special polymeric compatibilisers based on maleinised polypropylene with additions of elastomers of different nature. Secondly, it involves the use of the method of dynamic vulcanisation in the process of reactive extrusion of a PP/BNKS-18AMN blend with a peroxide modifying system including as a coagent a complex of polar vinyl monomer (maleic acid polyester and ethylene glycol) with aramine industrial antioxidant Diafen FP. Determination of the principal physicomechanical characteristics of the composites revealed that only the combined use of these two methods of modification makes it possible to achieve a significant shift in the level of impact strength of PP/NBR composites without adversely affecting other indices, with control of the flow of the end products. Here, the most effective compatibilisers were maleinised blends of polypropylene with non-polar elastomers: ethylene–octene copolymer (Engage 8842) and ternary ethylenepropylene rubber (Royalene 563). It is assumed that a probable cause of the improvement in properties of the polymer blends is the considerable increase in the degree of dispersion of the rubber phase of the NBR in the polypropylene matrix under the action of the modification processes described above.

Interfacially modified LDPE/GTR composites with non-polar elastomers: From microstructure to macro-behavior

This paper provides some new insights into the mechanism of interaction and modifications in thermoplastic composites based on low density polyethylene (LDPE), ground tire rubber (GTR) and non-polar elastomer. The composites were prepared using a co-rotating twin-screw extruder at variable LDPE/GTR ratio and constant elastomer content. Two types of commercial elastomer were applied: styrene-butadiene-styrene (SBS) block copolymers (Kraton®) with different topologies (linear/branched) and partially cross-linked butyl rubbers (Kalar®) with different Mooney viscosities. Processing characteristics, static mechanical properties (tensile strength, elongation at break, hardness), dynamic mechanical properties, thermal properties and morphology of the resulting thermoplastic composites were investigated. Microstructure analysis shows that modification of LDPE/GTR composites with non-polar elastomers caused encapsulation of GTR particles within the elastomer phase. This phenomenon has significant influence on macro-behavior of thermoplastic composites based on LDPE/GTR blends. The results indicate that SBS copolymer improves interfacial interactions between GTR and LDPE, which enhances mechanical and thermal properties of the composites. On the other hand, cross-linked butyl rubber showed partial compatibility with LDPE and low compatibility with GTR particles.

Phase Morphology and Mechanical Properties of Rubber-Toughened Polypropylene Nanocomposites: Effect of Elastomer Polarity

The objective of this work was to investigate the effect of elastomer polarity on phase structure and mechanical properties of PP nanocomposites. The nonpolar and polar elastomers studied were polyethylene octene (POE) and polyethylene octene grafted maleic anhydride (POEgMAH), respectively. The results from mechanical studies showed that the POEgMAH-toughened polypropylene nanocomposites have higher Izod impact strength but lower tensile and flexural properties than the unmaleated ones. X-ray diffraction (XRD) was used to characterize the formation of nanocomposites. XRD studies revealed that intercalated rubber-toughened PP nanocomposites (RTPPNC) had been successfully prepared where the macromolecule segments PP were intercalated into the interlayer space of organoclay. XRD also indicated that the incorporation of polar POEgMAH elastomers into PP nanocomposites contribute to a better intercalation effect and formed a more exfoliated combinations structure compared to POE. Scanning electron microscope (SEM) was used for the investigation of the phase morphology and rubber particle size and particle-size distribution. SEM study revealed a two-phase morphology where POE as droplets dispersed finely and uniformly in the PP matrix. The POEgMAH-toughened PP nanocomposites shows a much finer dispersion of elastomer particles than POE-toughened PP nanocomposites.

Morphology and mechanical properties of HDPE/SRP/elastomer composites: effect of elastomer polarity

The effect of elastomer polarity on the morphology and mechanical properties of high-density polyethylene (HDPE) and scrap rubber powder (SRP) composites containing a polar or a non-polar elastomer was investigated. The morphological structure of the HDPE/SRP/elastomer composites was studied by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and interfacial tension ( γ AB). The results show that in the HDPE/SRP/elastomer composites, two types of morphological structures were observed, either an encapsulation of the filler by elastomer or a separate dispersion of the phases. In the HDPE/SRP/non-polar ethylene–octylene copolymer (POE) composites, some POE encapsulates SRP particles and some other POE disperses uniformly. However, in the HDPE/SRP/polar ethylene–vinyl acetate copolymer (EVA) composites, SRP and EVA disperse separately. Both the impact strength and elongation at break are higher in the HDPE/SRP/POE composites than in the corresponding HDPE/SRP/EVA composites.

Synthesis of silica in elastomer's matrix

AbstractWe tried to synthesise silica's fillers in polar and nonpolar elastomers. Di‐, tri‐ and tetraalkoxysilanes were used as a precursor of silica. Such functionality allowed us to obtain a filler with different ratio of crosslinking. We could expect some interactions between elastomer and silanes, which contained additional functional groups. We investigated vulcanizates by using the following methods: crosslink density in toluene and 10% solution of ethylenediamine in toluene, mechanical properties, IR microscopy, DMA. It appeared that alkoxysilanes influenced advantageously on elastomers and properties.