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Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives. To investigate the protective efficacy of unreduced and reduced forms of the condensation product of D,L-camphor and p-ethoxyaniline in nitrile butadiene rubber formulations when compared with the conventional stabilizer N-isopropyl-N′-phenyl- p-phenylenediamine aged under laboratory and in situ climatic conditions in the tropics.Methods. The thermostabilizing effect of the condensation product of D,L-camphor and p-ethoxyaniline was evaluated by means of infrared spectroscopy using the dynamics of changes in the absorption bands of carbonyl and hydroxyl groups. The features of rubber vulcanization were studied by means of rotorless rheometry. Changes in the physical and mechanical properties of rubbers and degree of cross-linking were evaluated after thermo-oxidative aging in laboratory conditions. They also took into account the results of longterm exposure of samples in undeformed and deformed state in a tropical climate, taking into account meteorological data of the Can Gio climatic testing station.Results. It was found for the first time that condensation products of D,L-camphor and p-ethoxyaniline exhibit a stabilizing effect in formulations of rubbers based on polar nitrile butadiene rubber.Conclusions. According to the results of laboratory and in situ tests, the study established that the use of N-[(1RS,2RS)-camphan-2-yl]- 4-ethoxyaniline (reduced form) as an antifatigue agent is preferable. This is due to the presence of a mobile hydrogen atom at the nitrogen atom. The protective effect is manifested in terms of the better preservation of elastic-strength properties of rubbers with less change in hardness.

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, we prepared nitrile butadiene rubber (NBR) composites with fluorographene (FG) and carbon nanotubes (CNTs) as hybrid fillers by a solution‐blending method. The resulting composites xFG/yCNTs‐NBR, where x and y represent the loading of FG and CNTs respectively, show significantly improved physical and mechanical properties. The hybrid fillers can form a filler network in the rubber matrix, leading to efficient energy dissipation. As a result, when the mass ratio of FG to CNTs is 1:1 and the total filler loading is 20 phr, the tensile strength of 10FG/10CNTs‐NBR is as high as 12.1 MPa. Furthermore, due to inherent lubricating and oil‐repelling effects of FG, 10FG/10CNTs‐NBR shows an abrasion resistance index (ARI) of 187% and a volume change of 2.38% after 72 h of soaking in aviation oil, which are 24% higher and 48% lower than the corresponding values of unfilled NBR composites, respectively. These results indicate that the hybrid fillers can effectively enhance the mechanical, wear and oil resistant properties of the elastomer composites, which is conductive for application of the NBR‐based composites. [ABSTRACT FROM AUTHOR]

This study investigates the shelf life of nitrile butadiene rubber (NBR) based on age and temperature factors. Natural aging of nitrile butadiene rubber samples is performed under laboratory conditions for 2 years, followed by thermogravimetric analysis to evaluate Arrhenius parameters. Toop's equation is used to predict shelf life at 5% conversion rate. Model-free kinetic methods, including Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), and Kissinger, estimate shelf life at different temperatures for both virgin and naturally aged nitrile butadiene rubber. Results show close correlation between KAS and Kissinger methods, with slight variations in activation energy impacting shelf life. Fourier-transform infrared spectroscopy (FTIR) tests assess functional group changes with age. Virgin nitrile butadiene rubber activation energy: OFW-73.33 kJ/mol, KAS-68.43 kJ/mol. Aged nitrile butadiene rubber activation energy: OFW-72.57 kJ/mol, KAS-67.88 kJ/mol. Shelf life at 40°C: Virgin nitrile butadiene rubber - OFW-111.29 years, KAS-26.31 years. Aged nitrile butadiene rubber - OFW-89.01 years, KAS-22.37 years. These findings provide valuable insights for predicting and assessing nitrile butadiene rubber viscoelastic damper performance in engineering applications. [ABSTRACT FROM AUTHOR]

Rubber has a wide range of application prospects as an important material in the field of oil extraction and sealing rings. The effect of molybdenum disulfide (2H-MoS2) on the properties of the composites of antioxidant 4020 and nitrile butadiene rubber (NBR) was investigated. Two sets of composites, 4020/NBR and MoS2/4020/NBR, were modeled using molecular dynamics simulations. The mechanical, thermal-oxidative aging and tribological properties of 2H-MoS2 on NBR composites were investigated at 298 and 398 K, respectively, and the adsorption ability and reinforcement effect of 2H-MoS2 on NBR were analyzed from an atomic perspective. The mechanical studies showed that Young’s modulus of MoS2/4020/NBR composites was improved by about 28% and 23% compared with 4020/NBR composites at 298 and 398 K temperatures, respectively. Therefore, the mechanical properties of NBR composites were significantly improved by the addition of MoS2. Similarly, the properties such as solubility parameters, mean square displacement, and binding energy of MoS2/4020/NBR composites were improved, and the stability and thermal and oxygen aging properties of NBR composites were effectively improved after the addition of MoS2. Tribological studies also showed that the friction coefficients of MoS2/4020/NBR composites were reduced by about 30% and 25%, and the wear rates were reduced by 5% and 7% at 298 and 398 K, respectively, compared with those of 4020/NBR composites. Therefore, MoS2 successfully enhances the tribological characteristics of NBR composites. [ABSTRACT FROM AUTHOR]

Nitrile butadiene rubber (NBR) has received a lot of attention as a sealing material, and its tribological performance is a crucial factor in determining the efficiency with which it will operate under various operating situations. In this study, NBR specimens with varying degrees of cyanide content, namely low cyanide (DN401), medium cyanide (DN2850), medium‐high cyanide (DN3380), and high cyanide (DN4050), were selected to investigate their tribological behavior when subjected to NO.10 aviation oil. To emulate their frictional responses during startup and shutdown operations, all four types of NBR were assessed under dry conditions. As the cyanide content increased, the coefficient of friction (COF) dropped from 1.381 to 0.810 and wear rate dropped from 2.38 × 10−3 mm3/(N m) to 1.88 × 10−4 mm3/(N m). When employed in conjunction with NO.10 aviation oil, DN401 and DN3380 exhibited COFs of 0.0963 and a slightly higher value of 0.127, respectively. Following aging treatment at 80°C in NO.10 aviation oil, stress reduction reached 65.8%, indicating the poorest performance among the four variants of NBR. Considering the COF, wear rate, and aging performance, DN3380 emerges as the most favorable choice for practical applications, thereby offering valuable insights into the selection of nitrile rubber for sealing materials. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The elasticity and aging resistance of nitrile butadiene rubber (NBR) will be reduced by reinforced filler. Herein, we report that polydopamine (PDA) polymerized in situ on graphene oxide (GO) to obtain polydopamine‐graphene oxide (PDA‐GO) nanofiller for simultaneously improving strength, elasticity and thermal oxidative aging‐resistant performance of NBR. The structure, composition and morphology of PDA‐GO and NBR composites were characterized. The effect of PDA‐GO on the performance of NBR was investigated. Results show that PDA microspheres improved the dispersion of GO in matrix. With incorporation 3 phr of PDA‐GO, the tensile strength of NBR raised from 3.8 to 9.2 MPa. It is satisfactory that the elasticity is also improved significantly. PDA‐GO/NBR composite equips better thermal oxidative stability and aging resistance. The tensile strength of 3 phr‐PDA‐GO/NBR after aging is even 3.4 MPa higher than that of unfilled NBR before aging. Our work proposes an insight for the manufacture of rubber composites with high strength, elasticity and aging resistance. Highlights: GO modified by PDA is prepared via an in‐situ polymerization process.In situ polymerized PDA microspheres greatly promotes the dispersion of GO in NBR matrix.NBR filled with PDA‐GO shows a superior strength and elasticity simultaneously.PDA‐GO endows NBR with prominent performance in aging resistance. [ABSTRACT FROM AUTHOR]

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

The work is aimed at the development of an energy-saving technique involving the partial carboxylation of powdered lignocellulose products from the straw of annual agricultural plants and the use of the obtained products in rubber compositions as a water-swelling filler. Lignocellulose powder from oat straw (composition: α-cellulose—77.0%, lignin—3.8%, resins and fats—1.8%) was used for carboxylation without preliminary separation into components. Microwave radiation was used to activate the carboxylation process. This reduced the reaction time by 2–3 times. The synthesized products were analyzed by IR spectroscopy, thermogravimetry and scanning electron microscopy. Industrial product sodium carboxymethylcellulose (Na-CMC) was used as a swelling filler for comparison. The swelling fillers were fractionated by the sieve method; particles with the size of 0–1 mm were used for filling rubber compounds. The amount of swelling filler was 150 parts per 100 parts of rubber (phr). Due to the high filling of rubber compounds, plasticizer Oxal T-92 was added to the composition of a number of samples to facilitate the processing and uniform distribution of ingredients. The rubber composition was prepared in two stages. In the first stage, ingredients without swelling filler were mixed with rubber on a laboratory two-roll mill to create a base rubber compound (BRC). In the second stage, the BRC was mixed with the swelling filler in a closed laboratory plasti-corder rubber mixer, the Brabender Plasti-Corder® Lab-Station. Vulcanization was carried out at 160 °C. For the obtained samples, the physical-mechanical and sorption properties were determined. It has been shown that the carboxylated powdered lignocellulose from oat straw increases the strength properties of rubber in comparison with Na-CMC. It has been shown that when the carboxylated powdered lignocellulose from oat straw is introduced into the rubber composition, the degree of rubber swelling in aqueous solutions of various mineralizations increases by 50 and 100% in comparison with a noncarboxylated lignocellulose. [ABSTRACT FROM AUTHOR]

The effect of nanofiller additives containing cobalt oxide nanoparticles stabilized by a polymer matrix of high-density polyethylene (PE) on the structural features and properties of metal-containing nanocomposites based on isotactic polypropylene (PP) and nitrile butadiene rubber (NBR) has been studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. An improvement in strength and deformation parameters was revealed, which is apparently due to the synergistic effect of the interfacial interaction of cobalt-containing nanoparticles in the PE matrix with the components of the PP/NBR polymer composition. [ABSTRACT FROM AUTHOR]

In conventional fuel systems, biodiesel is an effective and eco-friendly substitute for petro-diesel. However, their compatibility with nitrile butadiene rubber (NBR) remains a challenge. This study reports that specific doses of gamma radiation can improve the compatibility of NBR with biodiesel and petrodiesel blends. Using small-amplitude oscillatory shear (SAOS) rheology and positron annihilation lifetime spectroscopy (PALS), we correlated the changes in the volume and weight of NBR after immersion in fuel blends with microstructural characteristics. Our results show that gamma radiation can significantly improve the compatibility of NBR with biodiesel but not with petrodiesel. Higher radiation doses significantly constrained NBR chain relaxation dynamics, as indicated by the increased relaxation modulus. PALS measurements showed reduced free-volume hole radii with increased radiation dose. Furthermore, we observed that the fuel diffusion mechanism was diffusion-controlled; however, the initial chain relaxation process played a role in the ingress of biodiesel into the NBR matrix. Our study highlights the potential of radiation processing to improve the biodiesel compatibility of NBR, which could lead to the development of efficient fuel-compatible NBR-based components. [ABSTRACT FROM AUTHOR]

A new class of active organic crosslinking agents for the vulcanization of NBR based on halogenmethyl-containing compounds has been found, allowing improvement significantly in the rheological and structural parameters of NBR. Gel content and Mooney viscosity in binary systems after plastification on rollers were studied. The sol fraction of cross-linked NBR (SKN-40+TCMCC) was found to be characterized by a bimodal MWD. Abnormally high value of W/ns of sol fractions is associated with the bimodal nature of their MWD and indicates the presence of gel in the elastomer. The value of η of the sol fractions in cross-linked NBR was found to be insignificant. The sol fraction of cross-linked HCPX elastomer was shown to have lower values of the specified parameters and lower content of highmolecular-weight fractions. The branching density ρ of macromolecules of sol fraction of cross-linked NBR was 1.90-2.3·10-3, i.e. on average corresponded to one monomer unit and two hundred branching nodes per molecule. [ABSTRACT FROM AUTHOR]

The increasing use of high-pressure hydrogen gas has heightened the need to understand material behavior in hydrogen-rich environments. Recent studies have shown that examining the pore-shaped damage in the cross-section of rubber materials exposed to high-pressure hydrogen can provide valuable insights into their resistance to such environments. This paper introduces an approach for training a deep learning model to detect hydrogen-induced pore-shaped damage. The study proposes a semi-automated labeling method and employs a modified faster R-CNN, implementing ResNet50-D, aspectual anchor box optimization, and dataset augmentation. To conduct the testing to validate the proposed method, acrylonitrile butadiene rubber was exposed to hydrogen at 96.6 MPa for 24 h. The dataset was created by analyzing damaged cross-sections using a scanning electron microscope. The detection results demonstrate that the proposed method outperforms both traditional and data-based conventional methods.

Nitrile butadiene rubbers (NBR) are widely used in sealing applications, such as O‐rings inside the pneumatic system of the French high‐speed train (TGV). In this application, a strong hardening of the NBRs alters the sealing function. Predicting the evolution of the mechanical properties during service life, especially the material hardening, is therefore a strategic issue to optimize time in maintenance operations of the TGV's pneumatic system. The main goal of this study is to reproduce the aging observed on a train's pneumatic system by performing thermo‐oxidative accelerated aging tests with different commercial nitrile rubbers at several temperatures and up to 2016 h. After achieving similar degradation to specimens aged on trains, aging mechanisms and effects have been investigated through different characterization techniques: infrared spectroscopy, swelling tests, X‐ray fluorescence spectrometry, differential scanning calorimetry, thermogravimetric analysis, and micro‐hardness measurements. The results obtained enabled us to identify and to relate aging mechanisms to aging conditions and to precisely determine and quantify the effects of physicochemical state evolution on the mechanical properties of each NBR considered. Extra crosslinks and oxidative functionalities form in the different elastomers, making them hard and brittle, and thus impacting the sealing function. [ABSTRACT FROM AUTHOR]

Post-vulcanised latex curing method was adapted in this study to develop nitrile butadiene rubber/graphene oxide (NBR/GO) membranes for oily wastewater filtration. This is a comparatively new method for solvent-free membrane preparation. Due to the fact that the oily wastewater could be discharged at different pH in industry, the pH reading of the oily wastewater in this study was varied from 4 to 10 to investigate its effect on the membrane performance in terms of tensile strength, permeation flux, and oil rejection efficiency. Performance of latex-based membranes over a range of pH has yet to be reported in literature. Thus, the knowledge from this work has significant impact on future applications of latex-based membranes to treat wastewater discharged at different ranges of pH. NBR/GO membranes were found to have good retention of tensile properties at all pH ranges. This feature is attributed to the crosslinks in the NBR matrix which provides a strong and stable three-dimensional network between the polymeric macromolecules. Moreover, with incorporation of 2 wt% GO, the NBR/GO membrane was able to achieve permeation flux of more than 500 L/m2.hr and oil rejection of more than 50% at all pH ranges. This can be attributed to the membrane's average pore size of 0.2810 µm and a water contact angle of 75°, both of which concurrently manifest oil rejection and water flux characteristics. The highest permeation flux and oil rejection of 2720.53 L/m2.hr and 91.88%, respectively, were achieved at a pH range of 6–7. [ABSTRACT FROM AUTHOR]

The results of the study of rheological and physical and mechanical properties of a mixed composition based on nitrile butadiene rubber BNKS-18AMN, ultra high molecular polyethylene GUR 4113, and chloroprene rubber DENKA S-40 are presented. It is shown that the introduction of 5 wt % CR into the mixed composition BNKS-18AMN/UHMWPE allows increasing the strength indicators, hardness, wear resistance, and frost resistance of the vulcanizates. [ABSTRACT FROM AUTHOR]

Clay modification by organic ammonium salts has been widely introduced in rubber/clay nanocomposites, but it is inapplicable in the polar rubbers to achieve high performance due to bad dispersion and poor compatibility. In this work, gel‐compounding method was utilized to prepare nitrile butadiene rubber (NBR)/clay nanocomposite, and then a hindered phenol antioxidant, triethylene glycol bis(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionate (AO‐245) with various contents, was mechanically blended to enhance the interactions in the nanocomposites. The elongation at break increases while the Shore A hardness, permanent set and stress at 100% or 300% strain decrease by adding AO‐245 into the nanocomposites. By adding only 5 phr AO‐245 in the nanocomposite, the tensile strength and elongation at break increased from 18.3 MPa and 521% to 20.5 MPa and 646%, respectively, which resulted from the repeated destruction/construction of the hydrogen bonds between AO‐245 and NBR. At high AO‐245 content, both clay networks and AO‐245 aggregate networks coexist in the nanocomposite, and the excess AO‐245 in the NBR matrix can form a separated phase leading to a new internal friction peak. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Science & Engineering (1673-2812) is the property of Journal of Materials Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Firefighters are exposed via multi-route exposure to a multitude of chemicals (PAHs, VOCs, flame retardants, dioxins, etc.) that may cause acute and long-term health effects. The dermal absorption of contaminants is a major contributor to the overall exposure and can be reduced by wearing appropriate personal protective equipment. As leather firefighters' gloves cannot be decontaminated regularly by wet cleaning, many Belgian firefighters wear supplementary undergloves made of nitrile butadiene rubber (NBR) to protect against the accumulation of toxicants. However, the safety of this practice has been questioned. In this commentary, the current practice and risks are outlined for the first time, assessed by an interdisciplinary working group of the Belgian Superior Health Council. As NBR sticks to the skin more at high temperatures, the contact time on removal will be prolonged, posing an additional risk for deeper burns. However, based on the physicochemical properties of NBR and the existing experience of firefighters and burn centers, it is estimated that such incidents occur relatively rarely in practice. On the other hand, the risk of repeated exposure to contaminated gloves if no undergloves are worn is unacceptable. Despite the slightly increased risk for deeper burns, it is concluded that wearing disposable NBR gloves under regular firefighters' gloves is an appropriate and effective preventive measure against toxic contamination. The nitrile butadiene rubber must always be fully covered to avoid any contact with the heat. [ABSTRACT FROM AUTHOR]

The conventional covalent crosslinking has been commonly utilized in rubber/clay nanocomposite, but stronger crosslinking bonds such as coordination crosslinking should be introduced to further improve the mechanical properties. Herein, we first prepared the nitrile butadiene rubber (NBR)/clay nanocompound via gel compounding method, and then copper sulfate pentahydrate (CSP) was introduced to prepare NBR/clay/CSP nanocomposites via the coordination crosslinking. The nanocomposites with higher CSP content and more curing time exhibited higher crosslinking density and glass transition temperature, because more rubber chains were immobilized by the CSP particles. Similar effect on mechanical properties was found by increasing the CSP content and by prolonging the curing time. By optimizing the curing time, the best mechanical properties was achieved for the NBR/clay10/CSP20 nanocomposite cured for 70 min with tensile strength of 37.4 MPa and elongation at break of 354%, which was far beyond the ordinary rubber/clay nanocomposites.

This study details microwave-absorbing materials made of natural rubber/nitrile butadiene rubber (NR/NBR) blends with multi-walled carbon nanotubes (MWCNTs) and molybdenum disulfide (MoS2). The mechanical blending method and the influences of fabrication on the morphology and microwave-absorbing performance of resulting compounds were logically investigated. It was found that interfacial differences between the fillers and matrix promote the formation of MWCNTs and MoS2 networks in NR/NBR blends, thus improving microwave-absorbing performance. Compared with direct compounding, masterbatch-based two-step blending is more conducive to forming interpenetrating networks of MWCNTs/MoS2, endowing the resulting composite with better microwave attenuation capacity. Composites with MWCNTs in NR and MoS2 in NBR demonstrate the best microwave-absorbing performance, with a minimum reflection loss of −44.54 dB and an effective absorption bandwidth of 3.60 GHz. Exploring the relationship between morphology and electromagnetic loss behavior denotes that such improvement results from the selective distribution of dual fillers, inducing networking and multi-component-derived interfacial polarization enhancement. [ABSTRACT FROM AUTHOR]

The enhanced adhesion of polyurethane (PU) adhesives with ethylene-vinyl acetate (EVA) midsole and vulcanized acrylonitrile-butadiene rubber (NBR) outsole using cold atmospheric pressure plasmas (CAPPs) was investigated at short exposure durations of 27–64 s. A 100% of failure at EVA cohesive, after T-peel test of CAPPs-treated EVA/PU adhesive/CAPPs-treated NBR, proves that N2-air CAPPs can efficiently work as a surface modification on EVA and NBR soles, compared with 100% of failure at PU adhesive/NBR interface after T-peel test of bonded as-received EVA/PU adhesive/as-received NBR. This study demonstrates that N2-air CAPPs significantly affect the surface polar properties and the enhanced adhesive strengths of EVA and NBR soles. Hydrophobic surfaces of EVA and NBR with small polar surface free energies (PSFEs) of 2.4 and 1.7 mN/m could be turned into highly polar surfaces as the values of PSFEs are respectively raised to 39.9 and 35.2 mN/m after the surfaces were treated by N2-air CAPPs. Increased compositions of O and N atoms for EVAs and NBRs by N2-air CAPPs have been identified to bond well with PU adhesives. For further insight into the treatment reaction on the surfaces of EVA and NBR using CAPPs, plasma active species of N2-air CAPPs were detected with optical emission spectroscopy. [ABSTRACT FROM AUTHOR]

The impact of the amount of water-swellable filler sodium carboxymethylcellulose of Polycell-9B grade (particle size 1.0–2.0 mm) on the complex of physical and mechanical properties of limited swelling rubbers based on nitrile butadiene rubber of BNKS-28 AMN grade with a sulfur vulcanizing system was studied. The composition with a ratio of the rubber compound without swelling filler to sodium carboxymethylcellulose was varied in the range (65–35) : (35–65) (wt. parts). It was established that the introduction of a swelling filler into the rubber compound has virtually no effect on the time to achieve the optimal vulcanization time and is 10 min at a temperature of 170°C. It was shown that the introduction of sodium carboxymethylcellulose leads to a decrease in the deformation-strength properties of rubbers, however, the strength characteristics of modified rubbers allow the use of the developed rubber compositions for the manufacture of sealing elements of water-swellable packers. It was revealed that with an increase in the proportion of the swelling filler, sodium carboxymethylcellulose, the vulcanizate exhibits a higher sorption capacity in aqueous media with different pH. [ABSTRACT FROM AUTHOR]

Experimental determination of mechanical properties of rubber composites, such as tensile strength and hardness, involves complex multistage preparation procedures that are laborious and expensive. In this study, a hybrid filler of carbon black (CB) along with a sustainable filler of lignin is added for reinforcement in the nitrile butadiene rubber (NBR) matrix, with the total filler content varying from 10 parts per hundred rubber (phr) to 80 phr. This work aims to develop a data-driven predictive model for the mechanical properties of rubber composites. An artificial neural network (ANN) model using multilayer feed-forward back-propagation has been created to forecast the tensile strength ( Ts ) and hardness ( Hd ) of rubber composites. The model predicts the uniaxial tensile response and hardness using input parameters that include total filler and lignin loading levels. The effectiveness of the suggested prediction method was demonstrated by statistical analysis using confidence intervals, showing a prediction error between 5.47% and 3.23% for the Ts and between 3.03% and 1.85% for Hd at 95% confidence intervals. A sustainable green band could be defined in the developed model, which is handy for designers to replace CB with lignin in various NBR based products, such as hoses, seals, etc., without compromising on tensile strength and hardness.

The work is aimed at the development of an energy-saving technique involving the partial carboxylation of powdered lignocellulose products from the straw of annual agricultural plants and the use of the obtained products in rubber compositions as a water-swelling filler. Lignocellulose powder from oat straw (composition: α-cellulose—77.0%, lignin—3.8%, resins and fats—1.8%) was used for carboxylation without preliminary separation into components. Microwave radiation was used to activate the carboxylation process. This reduced the reaction time by 2–3 times. The synthesized products were analyzed by IR spectroscopy, thermogravimetry and scanning electron microscopy. Industrial product sodium carboxymethylcellulose (Na-CMC) was used as a swelling filler for comparison. The swelling fillers were fractionated by the sieve method; particles with the size of 0–1 mm were used for filling rubber compounds. The amount of swelling filler was 150 parts per 100 parts of rubber (phr). Due to the high filling of rubber compounds, plasticizer Oxal T-92 was added to the composition of a number of samples to facilitate the processing and uniform distribution of ingredients. The rubber composition was prepared in two stages. In the first stage, ingredients without swelling filler were mixed with rubber on a laboratory two-roll mill to create a base rubber compound (BRC). In the second stage, the BRC was mixed with the swelling filler in a closed laboratory plasti-corder rubber mixer, the Brabender Plasti-Corder® Lab-Station. Vulcanization was carried out at 160 °C. For the obtained samples, the physical-mechanical and sorption properties were determined. It has been shown that the carboxylated powdered lignocellulose from oat straw increases the strength properties of rubber in comparison with Na-CMC. It has been shown that when the carboxylated powdered lignocellulose from oat straw is introduced into the rubber composition, the degree of rubber swelling in aqueous solutions of various mineralizations increases by 50 and 100% in comparison with a noncarboxylated lignocellulose.

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

To enhance the damping properties of nitrile butadiene rubber (NBR), the elastomer used was blended with chlorinated paraffin 52 (CP52) to prepare NBR/CP52 composites. The results showed that CP52 could significantly enhance the damping properties of NBR and shift the glass transition temperature (Tg) to lower temperatures. Molecular dynamics models of the CP52/NBR system were established, and the damping properties of the CP52-reinforced NBR were investigated using molecular dynamics (MD) simulations. Through the combination of MD simulations and the experimental results, the essential mechanism of the enhanced damping properties of the NBR was methodically expatiated and was ascribed to the Cl-CP-H····NC-NBR (type I) and CP-Cl····H-NBR-CN (type II) analogous hydrogen bonds formed between NBR and CP52. The higher the CP52 content, the higher the analogous hydrogen bond concentration, and the better the damping properties of the CP52/NBR composites. The experimental results were very consistent with the MD simulation results, meaning that the combination method can provide a new means to optimize the design of damping materials and broaden the application range of small polar molecules in the damping modification of polar rubber materials. [ABSTRACT FROM AUTHOR]

Nitrile rubber (NBR) is commonly used as a stator rubber for screw pumps because of its excellent mechanical properties. However, under high‐temperature conditions, using NBR for long‐term operations is difficult, since it is highly susceptible to a thermal‐oxidative aging phenomenon that leads to its failure. In this study, the thermal‐oxidative aging behavior of graphene and graphene oxide (GO) in an NBR composite system was investigated using simulated molecular dynamics at 298 K and 348 K. The results showed that Young's moduli of graphene/NBR and GO/NBR composite systems were enhanced by about 33% and 44%, respectively, when the temperature was increased. That is, adding graphene and GO improved the resistance of NBR composites to elastic, bulk, and shear deformation, playing an important role in slowing down the thermal and oxygen aging of rubber. Furthermore, the binding energy, mean square displacement, and free volume fraction of the NBR composite systems were analyzed. The abundant oxygen‐containing functional groups in GO increased the intermolecular interaction force between GO and NBR and effectively inhibited the migration of antioxidants 4020. Therefore, GO retards the thermal and oxygen aging of NBR composite systems more effectively. [ABSTRACT FROM AUTHOR]

A domestic composite material based on silicon carbide and nitrile butadiene rubber was used to identify volatile substances of banana, banana flavor, and creamy chewing candies by passive adsorption in combination with thermal desorption GC–MS. This method can be used to determine a wide range of compounds, for example, esters of carboxylic acids, terpenoids, aldehydes, aromatic hydrocarbons, alkanes, heterocyclic compounds, phenols, glycerides, and fatty acids. The obtained chromatographic profiles of the samples were compared. In the chromatogram of "Banana" flavor, five peaks (out of eight) corresponded to the compounds that form the aroma of a banana, and in the chromatogram of "Love is" candies with banana flavor, three corresponding peaks (out of 21) were found. [ABSTRACT FROM AUTHOR]

Zirconium phosphate (α‐ZrP) was modified by o‐phenylenediamine (OPD) grafting to its surface, named ZPD, and used to improve thermal‐oxidative stability of nitrile butadiene rubber (NBR) by direct blending method. The results of Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), X‐ray diffraction, and contact angle test, demonstrated that OPD was grafted to the surface of α‐ZrP successfully. Scanning electron microscopy results showed that OPD could effectively improve the interaction between α‐ZrP and NBR and a better the dispersion of α‐ZrP in the rubber matrix. The fracture strength of the NBR composites was increased by 3.3 Mpa with the addition of 3 phr ZPD fillers, respectively, compared with unmodified NBR/α‐ZrP composites. In addition, TGA, DMA, and FWO analysis showed ZPD fillers, combined lamellar barrier of α‐ZrP with radical trapping ability of OPD, could retard oxidative cross‐linking and fracture reaction of rubber chains, and improve the thermal‐oxidative aging resistance of the NBR composites. This work provides a practical and effective methodology for surface modification of α‐ZrP and preparation of high‐performance NBR composites. [ABSTRACT FROM AUTHOR]

An automotive sealed chain consisting of an elastomeric seal between chain plates prevents the entry of external contaminants. But, the presence of a seal induces high transmission loss due to the frictional force. In the present study, a comparative transmission loss test between two ANSI-B29.1 520 series sealed chains of equal geometric dimensions (5/8" pitch) was carried out. The tests revealed a significant difference of 38% in their transmission losses between the chains. To understand these observed differences in the chain performance, the material analysis of the seals (nitrile butadiene rubber) was performed, which showed a significant difference in their composition. The increased seal hardness due to difference in chemical properties resulted in a 21% increase in friction coefficient between the seal and the plates. The seal thickness reduction, the effect of lubricant, and the difference in the frictional forces between chains yielded differences in the transmission losses. [ABSTRACT FROM AUTHOR]

Binders with energetic plasticizers besides boosting energy also enhance the structural integrity of the propellant composition. In recent energetic compositions, energetic plasticizers such as NG, BTTN, DEGDN and TEGDN replace conventional plasticizers as they possess positive heat of the explosion and energetic groups in the same molecule. Energetic groups impart enhanced potential for delivering superior performance. In the present paper, a comparative study is done between NBR based composite solid propellant formulations with energetic (DEGDN and TEGDN) and non‐energetic (DAP and DBP) plasticizers. The predicted theoretical performance of non‐aluminized and aluminized propellants shows that DEGDN/TEGDN based propellants are more energetic than that of DAP/DBP propellants. The viscosity (768 Pa.s), density (1748 kg/m3), cal‐val (5426.64 J/g), burning rate (4.21 mm/s) of DBP and DAP based propellants are on the lower side than DEGDN and TEGDN based propellants. End of mix viscosity and burning rate of energetic plasticizer based compositions is approximately twice of the inert plasticizer based compositions. There is up to 60 % increase in TS and modulus while elongation is reduced by 20 %. Pressure index increases from 0.159 to 0.310 for DBP to DEGDN based propellant. The study shows that high performance high burning rate propellant can be designed with DEGDN. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWCNT) were widely used in nano‐polymer materials due to their excellent electrical and thermal conductivity and mechanical properties. However, the dispersion of MWCNT in the rubber matrix was usually poor due to their large aspect ratio and tendency to agglomerate. The main innovation of this technology was that the non‐covalent modification did not destroy the surface structure and original properties of MWCNT, which was a breakthrough compared to the previous covalent modification. The obtained IL‐MWCNT was still distributed in the water a month after sonication. The microstructural development of the filled network and the uniform dispersion of MWCNT in the presence of IL were analyzed by TEM. The apparent physical (cation–π/π–π) interactions between MWCNT and IL were characterized by Raman spectroscopy and thermal gravimetric analysis (TGA). The high‐performance composites of IL‐MWCNT and nitrile butadiene rubber (NBR) or nitrile butadiene rubber latex (NBRL) were prepared by the liquid latex blending method. The mechanical properties of the composites were improved due to the uniform distribution of IL‐MWCNT in the matrix. As found in this work, the addition of 3 phr of IL increased the mechanical properties of the composites significantly. The continued addition of IL affects the dispersion of MWCNT in the composites due to the plasticizing and diluting effects of IL, which results in a decrease in the mechanical properties. This study provides a simple, environmentally friendly method for the development of IL‐MWCNT composites. [ABSTRACT FROM AUTHOR]

In this work, we described a simple method to manufacture a novel nitrile butadiene rubber (NBR) filled with cupric sulfate (CuSO4) and tetramethylthiuram disulfide (TMTD) via simple mixing and heat pressing. Cure characteristics analysis, the motion capability of polymer segments, physical properties, micromorphology, swelling properties and dynamic characteristics were explored comprehensively. The results demonstrated that the three-dimensional network was cross-linked by the metal coordination interactions between the nitrile group and copper ion. The cure curve, tensile strength and crosslinking density exhibited a considerable increasing with the addition of TMTD in NBR/CuSO4 compounds, which was due to the synergistic effect between Cu2+ and Me2NCSn• (n = 1–2) radicals generated by the pyrolysis of TMTD, resulting in the formation of the hyperactive compounds [Cu(SnCNMe2)]•2+ and promoting the coordination crosslinking between -CN and Cu2+ significantly. The NBR/CuSO4/TMTD vulcanizates induced by the synergistic effect would play a crucial role in practical application for the excellent physical properties. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWCNTs) are used as a universal additive to increase the mechanical and electrical properties of materials. In this work, we introduced SWCNTs in nitrile butadiene rubbers filled with 60 phr carbon black using concentrates of predispersed SWCNTs in a solution of nitrile butadiene rubber with dibutyl phthalate. It is shown that the addition of 0.15 wt % of SWCNTs allowed decreasing the specific volume electrical resistivity by four orders from 2.3 × 106 to 7.9 × 102 Ω cm and increasing the tensile moduli at 50% and 100% elongation by 50% and 30%, respectively. The tensile moduli at 50% and 100% elongation and the tear resistance linearly depend on the concentration of SWCNTs in the nanocomposite for the studied concentration range up to 0.5 wt %, while the elongation at break and the tensile strength of the rubber do not change within the tolerance of measurements. The specific volume electrical resistivity depends on the concentration of SWCNTs in the rubber according to Kirkpatrick power law with a percolation threshold of 0.05 wt % and achieves 10 Ω cm at 0.5 wt % of SWCNTs. [ABSTRACT FROM AUTHOR]

The article presents the results of studies of the effect of technological parameters (temperature and mixing time), the content of peroxide used for the chemical modification of nitrile butadiene rubber, on its properties. As a result, the modes of grafting maleic anhydride to nitrile butadiene rubber in a rotary rubber mixer have been optimized, and the strength and adhesion properties of nonhardening sealants based on modified nitrile butadiene rubber with a content of bound acrylonitrile of 18 and 28 wt % have been evaluated. [ABSTRACT FROM AUTHOR]

When marine stern shafts operate under low speed and heavy load conditions, the metal shaft and water-lubricated bearing will be in a state of boundary lubrication or even dry friction. Poor lubrication can cause severe wear and friction-induced vibration, endangering the stealth performance of underwater vehicles. In this study, several typical liquid lubricants, including liquid paraffin, tung oil (TO), dimethyl silicone oil (DSO), ionic liquid (IL), and hexamethylene diisocyanate (HDI) were selected as the surface coatings for nitrile butadiene rubber (NBR). Using a tribological test machine with a high-precision vibration acceleration sensor, as well as scanning electron microscopy (SEM) and other techniques, the tribological performance and mechanisms of the NBR samples coated with different lubricants were studied under various working conditions. The results showed that the liquid lubricant significantly reduced the coefficient of friction of the NBR at high rotational speeds by over 92.2%. The sample coated with HDI showed obvious tribochemical wear, and coating with the rest of the liquid lubricants decreased the specific wear rate of NBR. According to the friction-induced vibration signals, we found that an increase in loading aggravated friction-induced vibrations, and the vibrational energy was mainly concentrated in the low frequency range. The liquid paraffin and TO coatings barely changed the vibration characteristics of the NBR, while the other three lubricants produced more friction-induced self-oscillations. In conclusion, compared to the other liquid lubricants, TO exhibited the best tribological performance. The finding of this study further our understanding of the friction and vibration behaviours of polymer materials, providing a reliable basis for designing composite materials with good lubrication and vibration damping performance.

Firefighters are exposed via multi-route exposure to a multitude of chemicals (PAHs, VOCs, flame retardants, dioxins, etc.) that may cause acute and long-term health effects. The dermal absorption of contaminants is a major contributor to the overall exposure and can be reduced by wearing appropriate personal protective equipment. As leather firefighters’ gloves cannot be decontaminated regularly by wet cleaning, many Belgian firefighters wear supplementary undergloves made of nitrile butadiene rubber (NBR) to protect against the accumulation of toxicants. However, the safety of this practice has been questioned. In this commentary, the current practice and risks are outlined for the first time, assessed by an interdisciplinary working group of the Belgian Superior Health Council. As NBR sticks to the skin more at high temperatures, the contact time on removal will be prolonged, posing an additional risk for deeper burns. However, based on the physicochemical properties of NBR and the existing experience of firefighters and burn centers, it is estimated that such incidents occur relatively rarely in practice. On the other hand, the risk of repeated exposure to contaminated gloves if no undergloves are worn is unacceptable. Despite the slightly increased risk for deeper burns, it is concluded that wearing disposable NBR gloves under regular firefighters’ gloves is an appropriate and effective preventive measure against toxic contamination. The nitrile butadiene rubber must always be fully covered to avoid any contact with the heat.

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This paper considers the features of the interfacial interaction in vulcanizates based on mixtures of nitrile butadiene rubbers (NBRs) with a random and block arrangement of acrylonitrile (AN) units and ethylene propylene diene elastomers (EPDMs) (ethylene-propylene ternary synthetic rubber) with a linear and branched chain structure and different stereoregularity of the propylene units. The effect of the fluctuation network of ethylene units with strong microblockness is established in branched EPDM and paracrystalline isotactic propylene structures in a linear EPDM on the direction and intensity of interfacial interaction. It is shown that the participation of NBR block defect structures in the interfacial interaction of these copolymers is minimized against the background of the contribution of the free volume fraction trans-1,4-butadiene units in the interdefect regions of the matrix near the defective NBR structures. [ABSTRACT FROM AUTHOR]

Vitrimers display great potential for application in various industries thanks to their high strength, reprocessability, and multi‐functions. However, it is still quite a challenge to fabricate rubber vitrimers as the facile designs in reversible crosslinking networks are always critical. Herein, inspired by mussel byssus, heterogeneous coordination networks are constructed in nitrile butadiene rubber (NBR) to develop novel vitrimeric structures composed of metal‐phenolic network (MPN) granules with dense zinc ions (Zn2+)–tea polyphenol (TP) bonds and a soft matrix containing few Zn2+cyano group (CN) coordination bonds. The resulting NBR composites show tunable reinforcement simply by altering the amount of Zn2+ ions. The reversibility of complexations endows the composites with good plasticity, recyclability, and stable shape memory properties. Plasticity at high temperatures changes vitrimeric networks, producing larger and spindle‐like MPN granules owing to their secondary self‐assembly. Despite these variations, the vitrimeric composites still maintain engineering plasticity‐based shape memory properties at a relatively large strain. Therefore, it is believed that the biomimetic strategies can well fabricate rubber composites with high strength, reprocessable, and shape‐memory performance. [ABSTRACT FROM AUTHOR]

Hypothesis: In recent years, much attention has been paid to the use of BaFe12O19 barium ferrite magnetic material in the manufacture of polymer composite magnets. Hence, nitrile butadiene rubber-polyvinyl chloride (NBR-PVC) polymer composite magnets containing barium ferrite alloy powder BaFe12O19 with particles less than 5 microns were made with optimal propertiesMethods: The effect of different amounts of barium ferrite magnetic powder in the polymer subs‌trate on the magnetic, morphological and mechanical properties of barium ferrite polymer magnets was inves‌tigated using SEM images and VSM diagrams and tensile tes‌t.Findings: NBR-PVC/ BaFe12O19 composite magnets containing 70 %wt NBR and 30 %wt PVC with 100 units of base rubber (phr) including 2 units of sulfur as baking agent, 4 units of zinc oxide as activator, 3 units of s‌tearic acid as lubricant, 2 units of tetramethyl thioram disulfide (TMTD) and 2 units of mercapto-benzythiazyl disulfide (MBTS) as accelerator and barium ferrite powder BaFe12O19 were fabricated with a particle size of less than 5 microns and a combination of different percentages as a magnetic agent. Among the samples made, N-P/F80 composite magnets with a ratio of 20:80 (powder:polymer) had the highes‌t saturation magnetism of Ms and the residual magnetization of Mr and the lowes‌t intrinsic coercivity of Hc. As expected, the bes‌t sample in terms of tensile s‌trength was N-P/F20 with a powder:polymer ratio of 80:20, and finally, according to all the results related to the magnetic, morphological and mechanical properties of the samples, the mos‌t suitable one in terms of good particle dispersion in the polymer subs‌trate and suitable tensile s‌trength and appropriate magnetic properties of N-P/F50 with 50:50 (powder:polymer) ratio was selected.