Brominated Butyl Rubber Research Articles

Anisotropic Elastomer Ionomer Composite-Based Strain Sensors: Achieving High Sensitivity and Wide Detection for Human Motion Detection and Wireless Transmission.

Anisotropic strain sensors capable of multidirectional sensing are crucial for advanced sensor applications in human motion detection. However, current anisotropic sensors encounter challenges in achieving a balance among high sensitivity, substantial stretchability, and a wide linear detection range. To address these challenges, a facile freeze-casting strategy was employed to construct oriented filler networks composed of carbon nanotubes and conductive carbon black within a brominated butyl rubber ionomer (iBIIR) matrix. The resulting anisotropic sensor based on the iBIIR composites exhibited distinct gauge factors (GF) in the parallel and vertical directions (GF∥ = 4.91, while GF⊥ = 2.24) and a broad linear detection range over a strain range of 190%. This feature enables the sensor to detect various human activities, including uniaxial pulse, finder bending, elbow bending, and cervical spine movements. Moreover, the ion-cross-linking network within the iBIIR, coupled with strong π-cation interactions between the fillers and iBIIR macromolecules, imparted high strength (12.3 MPa, nearly twice that of pure iBIIR) and an ultrahigh elongation at break (>1800%) to the composites. Furthermore, the sensor exhibited exceptional antibacterial effectiveness, surpassing 99% against both Escherichia coli and Staphylococcus aureus. Notably, the sensor was capable of wireless sensing. It is anticipated that anisotropic sensors will have extensive application prospects in flexible wearable devices.

Treatment of simulated brominated butyl rubber wastewater using monovalent anion perm-selective membranes through selective electrodialysis

Selective electrodialysis (SED) technology utilizing monovalent anion perm-selective membranes (MAPMs) has potential in resource recovery and wastewater treatment. However, the development and production of homogeneous MAPMs with high performance and scalability pose significant challenges. This study successfully scaling up a poly(alkyl-biphenyl pyridinium)-based MAPM suitable for large-scale SED applications and applies it to the treatment of mono-/di-valent anion wastewater. The pilot-scale membrane exhibits significantly higher perm-selectivity for various mixed anion systems compared to the commercial ACS membrane, and under the conditions of a current density of 40 mA cm−2, an initial dilute chamber solution of 3 L 0.5 mol/L NaCl, and a constant concentration chamber volume of 0.2 L, the pilot-scale membrane achieves a salt (NaCl) concentration of 18.6 wt% in just 70 mins in the membrane stack, with an energy consumption of 0.38 kWh kg−1. Furthermore, simulated brominated butyl rubber wastewater is treated with the aim of refining NaBr and separating SO42- ions. Several factors, such as applied voltage, initial concentration of the dilute chamber solution, feed flow rate, and dilute-to-concentrated chamber volume ratio are investigated to assess their effects on the treatment results. By continuously optimizing the operating conditions, a NaBr product with a concentration ratio of 6.2 and a purity of 97.8 % was obtained, with the Br- ion flux of 3.24 mol m-2 h−1 and an energy consumption of 0.319 kWh kg−1.

In-situ constructing hybrid cross-linked networks in brominated butyl rubber via amphiphilic graphene oxide cross-linkers: Retaining excellent gas barrier and mechanical properties after fatigue

Rubber/graphene nanocomposites as gas barrier materials have attracted great interest in recent years. However, it is still a challenge to construct strong covalent interfaces between nonpolar rubber matrix and graphene for retaining excellent gas barrier and mechanical properties of aircraft tires after fatigue. In this work, hybrid cross-linked networks in brominated butyl rubber (BIIR) are first proposed and in-situ constructed successfully via introducing the amphiphilic graphene oxide cross-linkers (R-aGO). R-aGO can participate in the curing of BIIR to form hybrid cross-linked networks, which can force R-aGO to move with BIIR synchronously during fatigue deformation due to strong interfaces between BIIR and R-aGO via covalent bonds. When R-aGO content is 3 phr, the BIIR/R-aGO nanocomposites show a 27 % improvement in gas barrier property, a 230 % increase in strength at 40 % strain (suffered deformation of aircraft tires), and a 229 % enhancement in tensile strength relative to conventional BIIR/aGO nanocomposites with interfacial modifiers. More importantly, BIIR/R-aGO nanocomposites still retain excellent gas barrier and mechanical properties even after 500,000 load cycles (40 % strain). This work provides a novel route to fabricate rubber/graphene nanocomposites with superior gas barrier and mechanical properties, especially after fatigue.

Morphology Control of Electrospun Brominated Butyl Rubber Microfibrous Membrane.

Brominated butyl rubber (BIIR) is a derivative of butyl rubber, with the advantage of high physical strength, good vibration damping performance, low permeability, aging resistance, weather resistance, etc. However, it is hard to avoid BIIR fiber sticking together due to serious swelling or merging, resulting in few studies on BIIR electrospinning. In this work, brominated butyl rubber membrane (mat) with BIIR microfiber has been prepared by electrospinning. The spinnability of elastomer BIIR has been explored. The factors influencing the morphology of BIIR microfiber membranes have been studied, including solvent, electrospinning parameters, concentration, and the rheological property of electrospinning solution. The optimal parameters for electrospinning BIIR have been obtained. A BIIR membrane with the ideal microfiber morphology has been obtained, which can be peeled from aluminum foil on a collector easily without being broken. Anti-bacterial property, the electrical conductivity of these membranes, and the mechanical properties of these samples were studied. The optimized BIIR electrospinning solution is Bingham fluid. The results of these experiments show that a BIIR membrane can be used in the field of medical prevention, wearable electronics, electronic skin, and in other fields that require antibacterial functional polymer materials.

Evaluation of the barrier and mechanical characteristics of bromo‐butyl rubber‐containing blends for use in inner liner of automotive tires

AbstractOne of the best elastomers for the inner liner of a tire is brominated butyl rubber (BIIR). On the other hand, cutting‐edge automobile technologies call for BIIR with enhanced curing, mechanical, and barrier qualities. Consequently, in this investigation, BIIR blends were created with different elastomers that have similar permeability qualities of BIIR but have improved physical properties. Elastomeric blends of BIIR with epoxidized natural rubber (ENR), hydrogenated nitrile rubber (HNBR), and polyepichlorohydrin rubber (CO) were prepared using a melt mixing procedure that could be scaled up for commercial use. The crosslinking behavior, physical, morphological, and barrier characteristics of the developed blends were assessed. The crosslinking properties of new blends revealed a 100% improvement in torque difference, indicating superior cocurability of them with other general‐purpose rubbers used in tire in comparison to the reference BIIR sample. It was also found that the newly developed blends have enhanced mechanical qualities without sacrificing the air impermeability of BIIR, which in turn gives the capacity to withstand high air pressures and thereby a decrease in rolling resistance.

A Novel Interface Agent for Preparation of High Gas Barrier Organic Montmorillonite/Brominated Butyl Rubber Nanocomposites

AbstractOrganic montmorillonite/brominated butyl rubber nanocomposites are prepared by improved solution blending, i.e., preparation of organic clay suspension and suspension blending with brominated butyl rubber solution by adding polytetramethylene ether glycol as interface agent. Scanning electron microscopy and atomic force microscopy show that polytetramethylene ether glycol has good dispersing effect on organic clay. Transmission electron microscopy and X‐ray diffraction analysis demonstrates that both intercalated and exfoliated structures are obtained in organic montmorillonite/brominated butyl rubber nanocomposites. The mechanical performances and the gas barrier properties of the organic montmorillonite/brominated butyl rubber nanocomposites are improved greatly, which proves that the high‐performance clay/rubber nanocomposites are prepared in nonpolar solvent.

Self-healing and enhanced anticorrosion coatings based on graphene-reinforced brominated butyl rubber ionomer

Heavy-duty anticorrosive applications usually require coatings to possess self-healing ability and high protection efficiency. In this paper, we propose a self-healing anticorrosion coating based on graphene (GP)-reinforced brominated butyl rubber (BIIR) ionomer. An ionomer with a reversible ionic network is fabricated by crosslinking BIIR with tert-butylpyridine and then compounded with GP nanosheets. The π-cationic interactions between GP nanosheets and pyridyl groups result in high interfacial contact. The interfacial contact promotes the dispersion of GP nanosheets in the polymer matrix, increasing the difficulty of corrosive chemical diffusion. Such material design enables the protection efficiency of the coating for a steel substrate to exceed 99 % in strong acid, strong alkali or high salt corrosive solutions. Furthermore, the coating exhibits high self-healing effectiveness in corrosive solutions. The recovered protection effectiveness is as high as 97.7 % after 24 h of self-healing. The coatings' remarkable anticorrosive and self-healing properties allow them to improve the service life of metallic equipment and components under harsh working situations.

Brominated Butyl Rubber Anticorrosive Coating and its Self-healing Behaviors

Brominated Butyl Rubber Anticorrosive Coating and its Self-healing Behaviors

Effects of boron nitride and carbon nanotube on damping properties, thermal conductivity and compression stress relaxation behavior of BIIR

AbstractAs highly integrated electronic components and devices are used under high electrical power and mechanical vibration, the thermal conductivity, damping properties, and compression stress relaxation of protection materials have become critical factors which affect the long‐term durability and reliability of the materials. Damping rubbers are widely used, but their thermal conductivity and compression stress relaxation are rarely studied. Herein, the effects of boron nitride (BN) and carbon nanotube on the damping properties, thermal conductivity, and compression stress relaxation behavior of brominated butyl rubber (BIIR) are investigated. BN increases the damping factor of BIIR and widens its effective damping temperature range. The maximum damping factor of BIIR composite with 12.3 wt% BN is 0.95, and the effective damping temperature range is −41 to 60°C. Moreover, the thermal conductivity of BIIR with 12.3 wt% BN is 0.46, much higher than that of BIIR. With increasing BN content, the thermal conductivity of BIIR/BN composites increases gradually, while their stress relaxation rate decreases. Carbon nanotube can further increase the thermal conductivity of BIIR/BN composites. BIIR/BN composites with high damping properties and thermal conductivity have a great application potential in the heat dissipation and vibration reduction of electronic devices.

Thermal Decomposition of Brominated Butyl Rubber.

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates, while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31 to 228.13 kJ·mol−1 at various heating rates. The non-isothermal degradation was found to be a first-order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggest that brominated butyl rubber has excellent thermal stability. This study can indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

Reinforcing self-healing and Re-processable ionomers with carbon black: An investigation on the network structure and molecular mobility

While most self-healing elastomers are mechanically weak, using the most commonly used carbon black (CB) to reinforce self-healing elastomers has not been reported. The possible reason is that the introduction of carbon black will cause complex changes in molecular dynamics, which leads to unpredictable self-healing effects. Herein, carbon black is introduced into a self-healing ionomer based on brominated butyl rubber (BIIR) grafted with tert-butyl pyridine (BP). Interestingly, the hierarchical microstructure and multilevel molecular dynamics of ionomers are well regulated by the strong interfacial π-cation interactions between CB and ionic aggregates. The strong interfacial interaction leads to high content of bound rubber, uniform dispersion of CB and compact physical network. Although such structural change has negligible influence on the segmental motion, it enhances the relaxation time and activation energy of ionic clusters, and thus endows the ionomer with high mechanical properties. Meanwhile, the structural change leads to higher relaxation temperature, thereby increasing the self-healing temperature. Despite this fact, the healing efficiency can still be regulated between 50% and 100%, depending on the filler content and temperature. Moreover, the CB reinforced ionomer is re-processable and recyclable. This study demonstrates that CB reinforcement is feasible to improve the mechanical properties of self-healing elastomers.

Assessment of various nano‐clays in bromobutyl rubber hydrogenated acrylonitrile butadiene rubber blend for improved gas barrier applications

AbstractFor the past few decades, butyl rubber (IIR) and its derivatives have been used primarily in air barrier applications. Recently other synthetic rubbers like hydrogenated acrylonitrile butadiene rubber (HNBR) has attracted attention for its air barrier properties. A blend of brominated butyl rubber (BIIR) and HNBR can be a potential and novel material with improved technical features as well as excellent processing behavior. In this article, laponite (RD) and bentonite (MT) nano‐clays have been used to prepare BIIR‐HNBR blend based nanocomposites. A detailed investigation of nanocomposite morphology has been done using the transmission electron microscope results. The improvement in terms of mechanical and gas barrier properties of BIIR‐HNBR nano‐clay composites over BIIR‐carbon black composites have been explored in detail. The air impermeability of BIIR‐HNBR blends shows a 20% improvement compared to the reference composite. The results clearly demonstrate the usefulness and effectiveness of the material in gas barrier applications.

Determination of Antioxidant 264 in the Butyl Rubber Stopper and the Compatibility with Recombinant Potent Antitumor and Antivirus Protein Injection.

Objective To establish a method for extraction and determination of antioxidant 264 (2,6-di-tert-butyl-4-methylphenol) in the brominated butyl rubber stopper for injection and migration study in recombinant potent antitumor and antivirus protein injection (Novaferon). Methods Dichloromethane-ethanol was adopted as the extraction solvent during the process of reflux extraction of antioxidant 264 in the brominated butyl rubber stopper. High-performance liquid chromatography (HPLC) was used for the determination of the migration of antioxidant 264 to Novaferon. The mobile phase consisted of acetonitrile-water (80 : 20, v/v). The flow rate was 1.5 mL/min. The detection wavelength was 280 nm. Results The linearity range was from 4.003 to 200.150 μg/mL (r2 = 0.99996), and the average recovery of antioxidant 264 was 97.8%. The applicability of the methodology was good, which can be used for the determination of antioxidant 264. The results indicated that antioxidant 264 was not detected in Novaferon after the accelerated test and three months of long-term test. Conclusion The established validated method in this study can be used for the determination of antioxidant 264 in the rubber stopper, and the brominated butyl rubber stopper has good compatibility with Novaferon.

Obtaining medium molecular characteristics of cation copolymerization of isobutylene and isoprene

Synthetic rubber has been interesting since the first days of research. Commercial isobutylene polymers are homopolymers and copolymers containing a small amount of isoprene. Isoprene has the great technical importance in connection with the production of synthetic rubbers that are close in structure and properties to natural rubber. These days, chlorinated and brominated butyl rubber derivatives have the highest sales volume. Butyl rubber is one of the synthetic rubber which is produced in quite large quantities on the world market. Commercial butyl rubber that is a copolymer of isobutylene and ˜1.5 %mol isoprene, is produced by carbocationic methods. There is a mathematical model of periodic isothermal process of copolymerization of isobutylene and isoprene using AlCl3 catalyst in the solution of CH3Cl in a periodic reactor consisting of four reactions, that are chain growth, two chain transfer reactions to solvent and reinitiation, in this article Nowadays, the cation polymerization for the synthesis of new materials of commercial interest rapidly develop and have the widespread use. One of such materials is butyl rubber, which is produced at -98°C in an inert methylchloride diluent in the presence of the AlCl3 initiator.

Reaction mechanism of halogenated rubber crosslinking using a novel environmentally friendly curing system

Iron (III) acetylacetonate (Fe (acac)) in the presence of triethanolamine (TEOA) was utilized as a novel crosslinking agent for halogenated diene rubber. Following the assumption that the mechanism of the crosslinking bases on the Heck-type reaction mechanism, which requires the presence of a halogen and an unsaturated carbon-carbon double bond, chloroprene rubber (CR) and brominated butyl rubber (BIIR) were utilized as rubber matrices. The results of FTIR spectra analysis confirm the proposed mechanism and indicate that a Heck-type reaction is feasible for performing a crosslinking of halogenated diene rubbers. The use of the Fe (acac)/TEOA curing system results in a significant torque increase during the vulcanization, which confirms the high activity of those compounds. The elimination of halogen from a rubber macromolecular structure or elimination of a basic environment of the crosslinking reaction results in a deactivation of the new curing system.

Constructing Oriented Two-Dimensional Large-Sized Modified Graphene Oxide Barrier Walls in Brominated Butyl Rubber to Achieve Excellent Gas Barrier Properties.

Brominated butyl rubber (BIIR) is widely used as tire lining, medical sealing material, and so on, due to its merits like high strength, low permeability, and high vulcanization activity. However, the gas barrier properties of BIIR need to be improved further to meet the requirements of certain special conditions such as high pressure (aircraft tire: 1.5 MPa). In this work, oriented two-dimensional (2D) large-sized modified graphene oxide (mGO) barrier walls in BIIR are successfully constructed based on the following processes: three-dimensional (3D) large-sized mGO hollow spherical shells in BIIR matrix are achieved from the core (water)-shell (mGO) structure in BIIR solution, which is obtained through the Pickering emulsion template method, and then are pressed into oriented 2D large-sized mGO barrier walls in the BIIR matrix. Such oriented 2D large-sized mGO barrier walls not only have an extremely large size between 50 and 120 μm but also are aligned perpendicular to the gas diffusion direction. Thus, even only with 0.7 wt % mGO, the nitrogen permeability of the BIIR composite is reduced by 91% relative to pristine BIIR and by 40% relative to the comparing sample with small mGO sheets. Therefore, this work provides a route to regulate the distribution of GO and thus can be a useful reference to fabricate rubber composites with superior gas barrier properties.

Effect of Solvent Polarity on Bromobutyl Rubber Isomerization

The reaction pathway of the isomerization in the process of butyl rubber bromination was proposed based on density functional theory (DFT) and MP2 calculations with the 6-31+G(d) basis set. The microstructural composition of the brominated butyl rubber was determined via proton nuclear magnetic resonance spectroscopy (1H-NMR).The transition state of isomerization reaction was identified. The geometries of the reactant, transition state, and product structures were optimized. The effect of solvation on model compounds was simulated using the polarizable continuum model (PCM). The energy barriers for isomerization reactions were calculated with different solvents (vacuum, n-hexane, and 245/105 mL n-hexane/dichloromethane (DCM) mixture). The increase in solvent polarity decreased the activation energy and facilitated the isomerization reaction. This finding was consistent with the experimental result.

Thermal analysis of halogenated rubber cured with a new cross-linking system

The aim of this work was to examine the influence of new curing agents proposed for brominated butyl rubber (BIIR) on the cross-linking process of rubber compounds and the thermal behavior of the vulcanizates. Rubber blends that were filled with carbon black and contained acetylacetonates of different transition metals in the presence of triethanolamine (TEOA) as new cross-linking agents were prepared. The performed studies showed that metal acetylacetonates (Me(acac)) are effective cross-linking agents for BIIR, which was confirmed by high values of the torque increment (∆M) and significant cross-linking degree of the vulcanizates (α(T)). The most active curing agent seems to be iron acetylacetonate (Fe(acac)). Its application results in a shorter optimal vulcanization time, lower onset vulcanization temperature and similar vulcanization enthalpy compared to the BIIR cured with a sulfur curing system. The BIIR vulcanizates cured with Me(acac) reveal good mechanical properties with tensile strengths in the range of 9–14 MPa and better damping properties comparing to the sulfur-cured rubber. The proposed curing agents do not significantly affect the thermal stability of the BIIR vulcanizates.

Preparation and Properties of Rubber Blends for High-Damping-Isolation Bearings

To improve the energy dissipation capacity of rubber isolation bearings, it is important to find a new rubber material with good applicability and high damping properties. Two types of blends were prepared using nitrile rubber (NBR), brominated butyl rubber (BIIR) and ethylene-vinyl acetate copolymer (EVA): NBR/BIIR and NBR/BIIR/EVA. The vulcanization, mechanical and damping properties of the blends were analyzed. The results show that both blends exhibit excellent vulcanization plateaus and mechanical properties. For NBR/BIIR, as the BIIR content increases, the complementary effects of NBR and BIIR afforded by blending are enhanced. Two damping peaks appeared in the tanδ-T curve and shifted toward lower and higher temperatures, respectively, which clearly widened the effective damping temperature range. However, the damping value in the valley of the tanδ-T curve was as low as 0.39. For NBR/BIIR/EVA, the addition of EVA greatly increased damping in the valley of the tanδ-T curve to approximately 0.54. EVA was observed to be the optimal polymer for improving the compatibility of the NBR/BIIR blend. Moreover, hot air thermal aging tests showed that both blends demonstrated good stability.

INSIGHTS INTO THE CURE CHEMISTRY OF BROMINATED BUTYL RUBBER

ABSTRACT The importance of dehydrobromination to the cure chemistry of brominated butyl rubber (BIIR) is demonstrated through a combination of cure rheometry studies and model compound experiments. These data show that, while HBr elimination to give an exomethylene conjugated diene is inevitable, subsequent reactivity is highly sensitive to acidity within the mixture. As a result, formulations containing acid scavengers such as epoxides or MgO produce cure dynamics and yields that differ markedly from those of unstabilized analogues. These differences in allyl cation reaction pathways underlie much of the known behavior of BIIR + ZnO compounds and have a substantial effect on the progress of sulfur-based cure formulations. In this report, allyl cation fragmentation and electrophilic addition mechanisms are developed from 1H nuclear magnetic resonance (NMR) and mass spectrometry analysis of model compounds, and their implications for sulfur, ZnO, and sulfur + ZnO vulcanization chemistry are detailed.