Search Results (33)

This paper aimed to evaluate the effect of cross-linking temperature on the rheological, mechanical, and thermal properties of CR/BR compositions cross-linked with zinc oxide, iron(III) oxide, or copper(II) oxide. Properties of CR/BR compounds were studied at four temperatures: 140, 160, 180, and 200 °C. The lowest activation energy of vulcanization was shown by blends cross-linked with ZnO, and the highest activation energy of vulcanization was shown by samples with Fe₂O₃. Blends cured with ZnO or Fe₂O₃ showed higher cross-linking activity than CuO. Higher temperatures enhanced the degree of cross-linking in the CR/BR composite cured with ZnO or CuO but slightly reduced it for the CR/BR/Fe₂O₃ vulcanizates. The highest tensile strength was observed for the CR/BR/Fe₂O₃ product. However, compositions cured with ZnO exhibited the best aging resistance. The CR/BR compounds cured with ZnO at high temperatures had the highest tear strength (16.8 N/mm), while samples containing CuO as a curing agent showed declining tear strength with temperature. DSC confirmed a single glass transition (~36 °C), indicating good elastomers dispersion. Infrared and SEM analyses confirmed effective cross-linking and blend compatibility. Full article

The transmission of vibrations generated by high-powered machines to the hands can lead to serious health problems and various work-related difficulties for the operators. These issues result in a loss of workforce and increased operational costs due to compensation payments made to affected workers. Exposure to hand–arm vibration can be controlled through the use of vibration damping gloves. In this study, the hand–arm vibration exposure of operators using a jackhammer in three different mines was measured with and without gloves, and the vibration damping ratio of each glove was calculated. One-way analysis of variance was performed to determine the difference between the vibration damping ratios (%) obtained from three separate field measurements of 12 different gloves, and significant differences were detected. In addition, vibration exposure was measured with and without gloves for operators using a vibrating sieve set with standard vibration in a laboratory environment. From both the field and laboratory measurements, the gloves made of chloroprene rubber provide the most effective protection. Full article

This study investigates the impact of ozone exposure on the hardness of synthetic rubber specimens (a blend of NR (natural rubber) and CR (chloroprene rubber)) through accelerated aging tests. Using a linear regression model, the research predicts the lifespan of rubber under real-world conditions and demonstrates how established experimental methods can yield novel insights when applied to synthetic rubber. The results show that ozone exposure significantly increases hardness within the first 10 days, stabilizing after day 12. Through analysis, this study calculates acceleration factors based on ozone concentration and temperature, estimating the practical lifespan of synthetic rubber under actual conditions to be approximately 25.76 years. These findings provide valuable indicators for evaluating the durability of synthetic rubber materials and predicting the longevity of rubber products in industrial applications. Furthermore, the research emphasizes the potential for improving lifespan prediction accuracy by incorporating non-linear models or machine learning approaches. Full article

This study aimed to investigate the properties of tin(II) oxide (SnO) as an unconventional cross-linking agent for chloroprene (CR) and styrene–butadiene (SBR) rubbers compositions. The use of tin(II) oxide results from the need to reduce the use of zinc oxide as a cross-linking agent due to environmental regulations and its toxic impact on aquatic environments. The studied elastomeric blends can be cross-linked with tin(II) oxide, and the results demonstrate the significant potential of this oxide in such applications. The CR/SBR vulcanizates cross-linked with SnO exhibit good mechanical properties and a high degree of cross-linking. The studies clearly show that the proportions of both rubbers as well as the amount of tin(II) oxide used influence the cross-linking of the CR/SBR blends and the properties of vulcanizates. FTIR spectrum analysis allowed the identification of the cross-linking mechanism, which followed the Friedel–Crafts alkylation reaction mechanism. The AFM analysis determined the miscibility of the rubbers and interelastomeric reactions, proving that the rubbers studied are partially miscible. The results of the oxygen index measurements indicated that the obtained vulcanizates showed flame resistance and self-extinguishing properties. Multivariate regression was performed to fit the models to the experimental value and to determine the influence of the content of the cross-linking agent and the CR and SBR proportions on the properties of the blends. Full article

Slurry erosion testing is essential for evaluating the durability of materials under erosive conditions. This study examines the slurry erosion behaviours of chloroprene rubber (CR) under varying impact conditions to assess its durability. Traditional mass loss methods and qualitative techniques, including microscopy, SEM, and AFM, were employed to analyse eroded CR samples. Results indicate that cumulative material loss in CR increases linearly with sand impingement after approximately 60 kg of sand and correlates with an impact energy of about 30 kJ. The highest erosion rate was found at an impact angle of 15°. Erosion mechanisms vary with impact angle, affecting surface topography from cutting and ploughing at lower angles to deformation and crater formation at higher angles. Despite their efficacy, these methods are time-intensive and costly. This paper presents a novel approach utilising gloss measurement for continuous, non-destructive monitoring of eroded rubber surfaces. Gloss measurements are 24 times faster than traditional mass loss methods. Correlating gloss values with cumulative material loss, steady-state erosion, and impact energy offers significant time savings and an enhanced understanding of the erosion process. Experimental results demonstrate the effectiveness of gloss measurement as a reliable tool in slurry erosion testing of rubbers. The quantitative output from gloss measurements could support proactive maintenance strategies to extend service life and optimise operational efficiency in industrial applications, particularly in the mining industry. Full article

In this study, we investigated how high-temperature, high-pressure hydrogen affects the optical properties of three kinds of sealing rubber (chloroprene rubber, ethylene propylene diene monomer, and acrylonitrile butadiene rubber) using pulsed terahertz waves. The optical properties of the rubber samples were analyzed before and after exposure to hydrogen (80 °C and 200 bar) for 72 h. The results showed that the terahertz waves had a shorter time delay and a lower signal intensity for all rubber types. The exposure response intensity, refractive index, and absorption rate also changed in the frequency domain. Raman and Fourier transform infrared spectroscopy were used for comparison, and a few peak shifts were observed. However, the Raman spectra had low signal quality, and the laser damaged the specimen. The study demonstrates that terahertz waves can be used as a non-contact non-destructive testing technique to evaluate the changes in sealing rubbers after hydrogen exposure. Full article

In order to study the self-healing performance of macroscopic fractures of asphalt mixtures, semicircular bending (SCB) tests were used to test 90# base asphalt mixtures, SBS (Styrene–Butadiene–Styrene) modified asphalt mixtures, and SBS + CR (Chloroprene Rubber) composite modified asphalt mixtures. The F-H-F (the asphalt mixture specimen was fatigued for a certain number of times, then healed under certain conditions, and then fatigued until destroyed) test was carried out, and the fatigue life recovery rate of the fatigue test before and after healing was defined as the healing index (HI). The gray correlation analysis method was used to judge the influence degree of influencing factors on fatigue–healing according to the correlation index. The results show the type of asphalt has the most significant influence on the healing ability of the asphalt mixture. In the case of complete healing, the fatigue–healing performance of the SBS + CR composite modified asphalt mixture was the best, followed by the SBS-modified asphalt mixture, and 90# base asphalt. When the healing temperature is close to the softening point of asphalt, the healing performance of 90# base asphalt is better when the healing temperature is low. When the healing time is longer, the healing performance is better, and there is an optimal healing time. The healing index decreased with the increase in the degree of damage. When the degree of damage is too large, the asphalt mixture will be difficult to heal. Full article

Designing and preparing chloroprene rubber (CR) with robust mechanical and excellent flame retardancy performance are challenging. In this work, a biomimetic design for high mechanical and flame-retardant CR by synchronous introducing of sacrificial bond (disulfide) crosslinked networks into the chemically crosslinked network is developed based on two new types of vulcanization reactions. Under the catalysis of $\mathrm{M}\mathrm{g}{\left(\mathrm{O}\mathrm{H}\right)}_2$, the dynamic bond cross-linked network is formed by the reaction between the amino group of cystamine dihydrochloride (CA) and the allylic chlorine group of CR, while the covalently crosslinked network is synchronously formed by two types of nucleophilic substitution reactions in series between $\mathrm{M}\mathrm{g}{\left(\mathrm{O}\mathrm{H}\right)}_2$ and CR. The disulfide bonds serve as sacrificial bonds that preferentially rupture prior to the covalent network, dissipating energy and facilitating rubber chain orientation, so a CA-0.5 sample (CR/CA(0.5 wt%)/$\mathrm{M}\mathrm{g}{\left(\mathrm{O}\mathrm{H}\right)}_2$ (10 wt%) with dual crosslinked networks exhibits excellent mechanical performance, and the tensile strength and elongation at the break of CA-0.5 are 1.41 times and 1.17 times greater than those of the CR-0 sample with covalently crosslinked networks, respectively. Moreover, the addition of $\mathrm{M}\mathrm{g}{\left(\mathrm{O}\mathrm{H}\right)}_2$ significantly improves the flame retardancy of CR. Full article

The purpose of this paper was to examine the possibility of producing new blends of hydrogenated acrylonitrile-butadiene and chloroprene rubbers (HNBR/CR) unconventionally cross-linked with silver(I) oxide (Ag₂O), and to investigate the physicomechanical properties of the obtained materials. From the obtained results, it can be concluded that HNBR/CR composites were effectively cured with Ag₂O, which led to interelastomer reactions, and the degree of binding of HNBR with CR was in the range of 14–59%. The rheometric and equilibrium swelling studies revealed that the cross-linking progress depended on the weight proportion of both elastomers, and the degree of cross-linking was greater with more content of chloroprene rubber in the tested blends. Interelastomer reactions occurring between HNBR and CR improved the homogeneity and miscibility of the tested compositions, which was confirmed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) analyses. The tensile strength and hardness of the obtained HNBR/CR/Ag₂O vulcanizates proportionally increased with the content of CR, while the tear strength showed an inverse relationship. The obtained new, unconventional materials were characterized by significant resistance to thermo-oxidative factors, which was confirmed by the high aging factor. Full article

Thermo-oxidative aging plays an important role in changing the properties of rubber materials; it significantly decreases the fatigue life of air spring bags and further causes safety hazards. However, due to the great uncertainty of rubber material properties, an effective interval prediction model has not been established considering the effect of aging on airbag rubber properties. To solve the problem, this study proposes an interval parameter correlation model that can more accurately describe rubber crack propagation characteristics by considering material uncertainty. Furthermore, an aging prediction model of the rubber crack propagation characteristic region is established based on the Arrhenius equation. The effectiveness and accuracy of the method are verified by comparing the test and prediction results under the temperature spectrum. The method can be used to determine the variations in the interval change of the fatigue crack propagation parameters during rubber aging and can guide fatigue reliability analyses of air spring bags. Full article

Multiple functional-material-filled nitrile butadiene rubber/chloroprene rubber (NBR/CR) acoustic composites were extensively studied and prepared. According to the orthogonal test table L25 (5⁶), 25 groups of samples were prepared by using a low-temperature one-time rubber mixing process. With tensile strength, average transmission loss, and damping peak as indexes, the influence degree of different factors and levels on the properties of acoustic composites was quantitatively discussed and analyzed. The matrix weight analysis was employed to optimize the material formula of rubber composites, and the corresponding influence weight was given. Results showed that the acoustic composite with blending ratio of 70/30 for NBR/CR matrix had preferable mechanical and acoustic properties; adding mica powder (MP) and montmorillonite (MMT) in matrix contributed to improve all above three indexes owing to their specific lamellar structures; hollow glass beads (HGB) had a positive influence on improving acoustic property due to its hollow microcavities, however, it had a negative impact on damping property because of the smooth spherical surfaces. Accordingly, the optimal formulation was found to be NBR/CR blending ratio of 70/30, MP of 10 phr (per hundred rubber), HGB of 4 phr, and MMT of 10 phr. Full article

Natural rubber (NR) exhibits good elasticity, flexural resistance, wear resistance, and excellent mechanical properties, and it has been widely used in aerospace, transportation, medical, and health fields. For NR, however, the resistance to thermal-oxidation and ozone aging is fairly poor. Although aging properties of NR can be significantly improved with the incorporation of chloroprene rubber (CR) according to some references, the miscibility between NR and CR, the morphologies of the binary blends, and so on are revealed ambiguously. In this work, molecular dynamics simulation (MD) and dissipative particle dynamics (DPD) simulation were carried out to predict the compatibility between natural rubber and chloroprene rubber in view of Flory–Huggins parameters. The morphologies of the blends were obtained with the use of the DPD method. The simulation results were furtherly examined by means of Fourier transform infrared spectroscopy (FT-IR) and dynamic mechanical analysis (DMA). It was found that the miscibility between NR and CR is poor. Nevertheless, the miscibility could be improved when the content of CR is 50% or 90%. In addition, spinodal decomposition with a critical temperature of 390 K would take place according to the phase diagram. Microphase structure such as spherical, lamellar, and bicontinuous phases can be found with different contents of CR in the blends with the results of morphologies analysis. Full article

This paper presents the influence of zinc on the cross-linking process, mechanical and dynamic properties, morphologies and balance of thermal degradation of blends containing chloroprene rubber (CR) and butadiene rubber (BR). The novel aspect of this research is a comprehensive approach presenting a new curing agent for the CR/BR blends to increase their cross-linking density and final properties, including non-flammability and low fire hazard. This is due to the need to find an alternative to zinc oxide, which is the standard curing agent for chloroprene rubber. The regulations of the European Union enforce a significant limitation on the use of this compound in elastomer technology, due to its harmful effect on aquatic organisms. In this paper, the CR/BR composites were cured with zinc and filled with natural silica fillers (sillitin or chalcedonite) or synthetic silica filler (aerosil). The investigation focused on the morphology characterization of the obtained compounds, their cross-linking degree, swelling, mechanical and dynamic properties, fire hazard and toxicity. The structure of cured CR/BR blends was characterized via scanning electron microscopy (SEM). The fire resistance studies were performed using cone calorimetry or oxygen index methods, whereas toxicity tests were performed with the use of the FB-FTIR (fluidized bed reactor coupled with FTIR analyzer) method. The results showed that obtained CR/BR products were characterized by satisfactory final properties. The properties determined by the oxygen index and cone calorimetry methods, including the behaviors of the tested CR/BR vulcanizates in fire conditions, showed that the produced compounds were characterized by a low fire hazard and can be classified as non-combustible rubber products. However, the toxicity of the decomposition products, determined at 450, 550 and 750 °C, was very high. Full article

Three different blending procedures were used to create multiwalled carbon nanotube (MWCNT)-modified chloroprene rubber (CR)/natural rubber (NR) blended composites (MWCNT/CR–NR). The effects of the blending process on the morphology of the conductive network and interfacial contacts were researched, as well as the resistance–strain response behavior of the composites and the mechanism of composite sensitivity change under different processes. The results show that MWCNT/CR–NR composites have a wide strain range (ε = 300%) and high dynamic resistance–strain response repeatability. Different blending procedures have different effects on the morphology of the conductive network and the interfacial interactions of the composites. If the blending procedures have wider conductive phase spacing and stronger interfacial contacts, the change in the conductive path and tunneling distance occurs more rapidly, and the material has a higher resistance–strain response sensitivity. Full article