ABSTRACT The low temperature sealing behaviors of five elastomer components used in aircraft hydraulic sealing systems were evaluated through a series of tests subsequent to exposure at 135 °C for a maximum of 28 days in air or hydraulic oil. These assessments encompassed standard material tests such as glass transition temperature (Tg), temperature retraction at 10% shrinkage, mechanical test, and compression set and a customized test to measure sealing force of a certain temperature. In addition, a low temperature gas leakage test was conducted. NBR stiffened upon aging with degradation of properties in an elongation loss, and Tg increased because chain mobility decreased due to increased crosslink density, and restoring force sharply decreased in cooling and in extracting plasticizer. In contrast, in the gas leakage test for both fluorocarbon rubber (FKM) and blends of epichlorohydrin with NBR (ECO), the Tg values showed good accordance, with minimal sealing temperature (Tseal), whether FKM or ECO were aged or not. However, the value of Tseal is significantly higher than that of Tg after NBR aging, indicating a complicated sealing mechanism. Thus, relying solely on standard material tests may not suffice for accurately forecasting the low temperature sealing performance in aircraft hydraulic sealing systems.
{"title":"LOW TEMPERATURE SEALING BEHAVIOR EVALUATION OF ELASTOMERS IN AIRCRAFT HYDRAULIC SYSTEMS","authors":"Siqi Wu, Fengliang Xiao, Qing Chen, Yongtang Liu, Baochun Guo","doi":"10.5254/rct.23.76992","DOIUrl":"https://doi.org/10.5254/rct.23.76992","url":null,"abstract":"ABSTRACT The low temperature sealing behaviors of five elastomer components used in aircraft hydraulic sealing systems were evaluated through a series of tests subsequent to exposure at 135 °C for a maximum of 28 days in air or hydraulic oil. These assessments encompassed standard material tests such as glass transition temperature (Tg), temperature retraction at 10% shrinkage, mechanical test, and compression set and a customized test to measure sealing force of a certain temperature. In addition, a low temperature gas leakage test was conducted. NBR stiffened upon aging with degradation of properties in an elongation loss, and Tg increased because chain mobility decreased due to increased crosslink density, and restoring force sharply decreased in cooling and in extracting plasticizer. In contrast, in the gas leakage test for both fluorocarbon rubber (FKM) and blends of epichlorohydrin with NBR (ECO), the Tg values showed good accordance, with minimal sealing temperature (Tseal), whether FKM or ECO were aged or not. However, the value of Tseal is significantly higher than that of Tg after NBR aging, indicating a complicated sealing mechanism. Thus, relying solely on standard material tests may not suffice for accurately forecasting the low temperature sealing performance in aircraft hydraulic sealing systems.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135719541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of EPDM in NR/BR blends for imparting ozone resistance is well known, as are the challenges of retaining desired mechanical properties in the cured rubber due to uneven distributions of carbon black and cure system across the blended polymer phases, favoring the NR/BR phase. This work explores how different sequential mixing options and mixing intensity can affect polymer phase dispersion and filler distribution, showing that excellent cured physical properties can be obtained using a commercially viable sequential mixing process where a proportion of the filler, cure system, and other compounding ingredients is first mixed into an EPDM masterbatch compound, which is subsequently used in a second mixing stage when it is combined with NR/BR at a suitable level to achieve good ozone resistance. Because only a proportion of the EPDM masterbatch is added to the second mixing stage, further filler, cure system, and other compounding ingredients are also added to reach the desired levels of the final compound. Variations of the sequential mixing process are reported, including the addition of a small amount of BR to the EPDM masterbatch and the use of an extended milling process. This study confirms that sequential mixing allows the retention of carbon black within the dispersed EPDM phase and shows how the EPDM masterbatch composition and the intensity of mixing can influence the phase morphology of EPDM/NR/BR blends. For comparison, an NR/BR control compound, typical of that used in tire sidewalls, is included in the evaluation. By applying transmission electron microscopy and atomic force microscopy imaging, phase domain sizes are evaluated quantitatively, and the Young’s moduli of the rubber phases are determined. The phase morphology is rationalized by the Hansen solubility parameters and the volume fractions of the rubber phases.
{"title":"PHASE MORPHOLOGY OF NR, BR, AND EPDM BLENDS PRODUCED BY AN OPTMIZED SEQUENTIAL MIXING PROCEDURE","authors":"C. Gögelein, P. Hough","doi":"10.5254/rct.23.76931","DOIUrl":"https://doi.org/10.5254/rct.23.76931","url":null,"abstract":"\u0000 The use of EPDM in NR/BR blends for imparting ozone resistance is well known, as are the challenges of retaining desired mechanical properties in the cured rubber due to uneven distributions of carbon black and cure system across the blended polymer phases, favoring the NR/BR phase. This work explores how different sequential mixing options and mixing intensity can affect polymer phase dispersion and filler distribution, showing that excellent cured physical properties can be obtained using a commercially viable sequential mixing process where a proportion of the filler, cure system, and other compounding ingredients is first mixed into an EPDM masterbatch compound, which is subsequently used in a second mixing stage when it is combined with NR/BR at a suitable level to achieve good ozone resistance. Because only a proportion of the EPDM masterbatch is added to the second mixing stage, further filler, cure system, and other compounding ingredients are also added to reach the desired levels of the final compound. Variations of the sequential mixing process are reported, including the addition of a small amount of BR to the EPDM masterbatch and the use of an extended milling process. This study confirms that sequential mixing allows the retention of carbon black within the dispersed EPDM phase and shows how the EPDM masterbatch composition and the intensity of mixing can influence the phase morphology of EPDM/NR/BR blends. For comparison, an NR/BR control compound, typical of that used in tire sidewalls, is included in the evaluation. By applying transmission electron microscopy and atomic force microscopy imaging, phase domain sizes are evaluated quantitatively, and the Young’s moduli of the rubber phases are determined. The phase morphology is rationalized by the Hansen solubility parameters and the volume fractions of the rubber phases.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48816024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Glycidyl methacrylate (GMA) was grafted onto styrene butadiene rubber (SBR) and silica by a solution grafting process. Successful grafting onto rubber and silica was confirmed by Fourier-transform infrared (FTIR) spectrometry, with the peaks at 1149, 842, and 1729 cm−1 attributed to the C–O stretching, the epoxy group, and the C=O stretching vibration of the GMA monomer, respectively. After grafting onto the silica surface, the peak at 842 cm−1 in the spectra disappeared, confirming the grafting reaction through the epoxy group. Grafting onto SBR was also confirmed by proton nuclear magnetic resonance (1H NMR) spectroscopy, and the SBR-GMA interaction was shown using two-dimensional 1H NMR spectroscopy. The grafted products were further characterized by thermogravimetric analysis (TGA) and differencial scanning calorimetry. Grafting density and grafting weight percentage of GMA-grafted silica were calculated using TGA: 10 and 20% GMA-grafted SBR and 20% GMA-grafted silica compounds and their vulcanizates were prepared. Rubber–silica interaction through grafted GMA was shown using FTIR spectroscopy for both types of vulcanizates. Dispersion of pristine and GMA-modified silica onto the SBR matrix was quantified using scanning electron microscopy and atomic force microscopy. Mechanical and dynamic mechanical properties of these GMA-modified vulcanizates were studied and compared with those of previously reported 3-octanoylthio-1-propyltriethoxysilane–modified vulcanizates. The effect of the state of dispersion of silica onto the physico-mechanical properties of the vulcanizates was investigated. The properties of the non-silane–modified systems were comparable with, and in some cases superior to, that of the new mercapto silane-modified systems in the energy-efficient tire application.
{"title":"GLYCIDYL METHACRYLATE AS A NON-SILANE MODIFIER IN RUBBER/SILICA COMPOSITES","authors":"Saikat Das, S. Chattopadhyay, A. Bhowmick","doi":"10.5254/rct.23.76994","DOIUrl":"https://doi.org/10.5254/rct.23.76994","url":null,"abstract":"\u0000 Glycidyl methacrylate (GMA) was grafted onto styrene butadiene rubber (SBR) and silica by a solution grafting process. Successful grafting onto rubber and silica was confirmed by Fourier-transform infrared (FTIR) spectrometry, with the peaks at 1149, 842, and 1729 cm−1 attributed to the C–O stretching, the epoxy group, and the C=O stretching vibration of the GMA monomer, respectively. After grafting onto the silica surface, the peak at 842 cm−1 in the spectra disappeared, confirming the grafting reaction through the epoxy group. Grafting onto SBR was also confirmed by proton nuclear magnetic resonance (1H NMR) spectroscopy, and the SBR-GMA interaction was shown using two-dimensional 1H NMR spectroscopy. The grafted products were further characterized by thermogravimetric analysis (TGA) and differencial scanning calorimetry. Grafting density and grafting weight percentage of GMA-grafted silica were calculated using TGA: 10 and 20% GMA-grafted SBR and 20% GMA-grafted silica compounds and their vulcanizates were prepared. Rubber–silica interaction through grafted GMA was shown using FTIR spectroscopy for both types of vulcanizates. Dispersion of pristine and GMA-modified silica onto the SBR matrix was quantified using scanning electron microscopy and atomic force microscopy. Mechanical and dynamic mechanical properties of these GMA-modified vulcanizates were studied and compared with those of previously reported 3-octanoylthio-1-propyltriethoxysilane–modified vulcanizates. The effect of the state of dispersion of silica onto the physico-mechanical properties of the vulcanizates was investigated. The properties of the non-silane–modified systems were comparable with, and in some cases superior to, that of the new mercapto silane-modified systems in the energy-efficient tire application.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47312717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Menglong Huang, L. Tunnicliffe, Shibai Liao, Bin Yang, Haixue Yan, J. Busfield
Natural rubber compounds reinforced with two different carbon blacks (N134 and N330) at various concentrations were characterized using very broadband dielectric spectroscopy from around 0.1 Hz to 0.3 THz using four different impedance and network analysis technologies. Percolation behavior was observed when the testing electrical frequency was below a certain range, which can be linked to the presence of percolated carbon black networks. When above a critical frequency level, the real part of AC conductivity or the permittivity tended to have a simple exponential relationship with the volume fraction of carbon black rather than a percolation-like behavior with the carbon black volume fraction and was no longer sensitive to carbon black networks. The AC conductivity derived via complex impedance was also strongly influenced by the choice of calculation model when the material was around or below the percolation threshold.
{"title":"BROADBAND DIELECTRIC CHARACTERIZATION OF CARBON BLACK–REINFORCED NATURAL RUBBER","authors":"Menglong Huang, L. Tunnicliffe, Shibai Liao, Bin Yang, Haixue Yan, J. Busfield","doi":"10.5254/rct.23.76983","DOIUrl":"https://doi.org/10.5254/rct.23.76983","url":null,"abstract":"\u0000 Natural rubber compounds reinforced with two different carbon blacks (N134 and N330) at various concentrations were characterized using very broadband dielectric spectroscopy from around 0.1 Hz to 0.3 THz using four different impedance and network analysis technologies. Percolation behavior was observed when the testing electrical frequency was below a certain range, which can be linked to the presence of percolated carbon black networks. When above a critical frequency level, the real part of AC conductivity or the permittivity tended to have a simple exponential relationship with the volume fraction of carbon black rather than a percolation-like behavior with the carbon black volume fraction and was no longer sensitive to carbon black networks. The AC conductivity derived via complex impedance was also strongly influenced by the choice of calculation model when the material was around or below the percolation threshold.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45457987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sulfur vulcanization is the most common crosslinking technology for unsaturated rubbers. To enhance our generic understanding of the structure–property relationships for sulfur-vulcanized rubber networks, we have studied two low-unsaturated rubbers, IIR and EPDM, and two high-unsaturated rubbers, NR and BR, at varying levels of sulfur curatives. In the first part of this series, the rheometer torque maximum and the compression set as a function of the temperature were discussed. In this second part, the effects of the level of the rubber unsaturation, the density of the trapped entanglements, and the chemical crosslink density on the network structure and tensile properties are discussed quantitatively. Our results reveal that the networks of the vulcanized BR and EPDM consist mainly of trapped entanglements. For EPDM and IIR, all unsaturation can be fully converted to sulfur crosslinks. The tensile strength at break (TS) of vulcanized EPDM and BR is independent of the permanent network density, which is the sum of the chemical crosslink density and the trapped entanglements. The TS shows a pronounced maximum versus the permanent crosslink density for vulcanized IIR and NR, due to the absence of the reinforcing effect of strain-induced crystallization (SIC) at low crosslink densities and the suppression of SIC at high crosslink densities. The elongation at break decreases with increasing network density, following a power-law relation. Mooney–Rivlin analysis of the stress–strain curves confirms our findings of the network structure as obtained from rheometry. However, an unexpected, curved course of the second Mooney–Rivlin parameter as a function of the varying sulfur content is observed for the EPDM samples, indicating that vulcanized EPDM has a different, entanglement-dominated network structure in contrast to IIR, NR, and BR.
{"title":"SULFUR VULCANIZATION OF LOW- VERSUS HIGH-UNSATURATED RUBBERS (IIR AND EPDM VERSUS NR AND BR): PART II—NETWORK STRUCTURE AND TENSILE PROPERTIES","authors":"C. Gögelein, M. van Duin","doi":"10.5254/rct.23.76991","DOIUrl":"https://doi.org/10.5254/rct.23.76991","url":null,"abstract":"\u0000 Sulfur vulcanization is the most common crosslinking technology for unsaturated rubbers. To enhance our generic understanding of the structure–property relationships for sulfur-vulcanized rubber networks, we have studied two low-unsaturated rubbers, IIR and EPDM, and two high-unsaturated rubbers, NR and BR, at varying levels of sulfur curatives. In the first part of this series, the rheometer torque maximum and the compression set as a function of the temperature were discussed. In this second part, the effects of the level of the rubber unsaturation, the density of the trapped entanglements, and the chemical crosslink density on the network structure and tensile properties are discussed quantitatively. Our results reveal that the networks of the vulcanized BR and EPDM consist mainly of trapped entanglements. For EPDM and IIR, all unsaturation can be fully converted to sulfur crosslinks. The tensile strength at break (TS) of vulcanized EPDM and BR is independent of the permanent network density, which is the sum of the chemical crosslink density and the trapped entanglements. The TS shows a pronounced maximum versus the permanent crosslink density for vulcanized IIR and NR, due to the absence of the reinforcing effect of strain-induced crystallization (SIC) at low crosslink densities and the suppression of SIC at high crosslink densities. The elongation at break decreases with increasing network density, following a power-law relation. Mooney–Rivlin analysis of the stress–strain curves confirms our findings of the network structure as obtained from rheometry. However, an unexpected, curved course of the second Mooney–Rivlin parameter as a function of the varying sulfur content is observed for the EPDM samples, indicating that vulcanized EPDM has a different, entanglement-dominated network structure in contrast to IIR, NR, and BR.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47851560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Windslow, A. Duncan, T. Hohenberger, J. Busfield
An elastomer’s tear behavior is commonly characterized through trouser tear tests. Using a well-understood analytical solution, the force at which the sample tears is used to calculate the elastomer’s tearing energy. By characterizing the tear behavior over a range of rates, a tear profile can then be built that describes the overall fracture resistance of the compound. However, some of the key assumptions that underpin the analytical solution may not be realistic, particularly in cases where the crack propagates in an unsteady manner. Within this article, these deviations are further studied through the use of physical testing and finite element modeling. The work demonstrates a heavy reliance on the sample’s thickness, beyond the levels currently appreciated. Furthermore, the work highlights the presence of a formation zone prior to the point at which the crack propagates uniformly. It is suggested that when evaluating an elastomer’s tear behavior, both the formation zone and propagation zone energies be captured.
{"title":"EVALUATING THE CRACK TIP FORMATION AND PROPAGATION ENERGY OF A TROUSER TEAR SPECIMEN","authors":"R. Windslow, A. Duncan, T. Hohenberger, J. Busfield","doi":"10.5254/rct-d-23-00010","DOIUrl":"https://doi.org/10.5254/rct-d-23-00010","url":null,"abstract":"\u0000 An elastomer’s tear behavior is commonly characterized through trouser tear tests. Using a well-understood analytical solution, the force at which the sample tears is used to calculate the elastomer’s tearing energy. By characterizing the tear behavior over a range of rates, a tear profile can then be built that describes the overall fracture resistance of the compound. However, some of the key assumptions that underpin the analytical solution may not be realistic, particularly in cases where the crack propagates in an unsteady manner. Within this article, these deviations are further studied through the use of physical testing and finite element modeling. The work demonstrates a heavy reliance on the sample’s thickness, beyond the levels currently appreciated. Furthermore, the work highlights the presence of a formation zone prior to the point at which the crack propagates uniformly. It is suggested that when evaluating an elastomer’s tear behavior, both the formation zone and propagation zone energies be captured.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42376800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The extent and nature of networks of carbon black particles in rubber compounds play a key role in determining the mechanical hysteresis and conductivity of rubber goods. It is well known that in uncrosslinked compounds, such networks display transient and time-dependent behavior when subjected to steps or ramps in shear and temperature (often called flocculation). This study probes the observed structural recoveries of carbon black networks following various levels of imposed shear strain histories. It is demonstrated that the level of shear experienced by the compound immediately before vulcanization can have a dramatic effect on the final dynamic mechanical properties of the subsequently vulcanized materials. Significant reductions in Payne effect occur when the timescales of shear-induced structural recovery, determined from rheological experiments, exceed the kinetics of vulcanization. Electrical conductivity/resistivity is also affected, especially for compounds formulated in the electrical percolation transition region. Furthermore, the microstructure of carbon black networks is tracked at different extents of recovery by using transmission electron microscopy thin section analysis and atomic force microscopy methodologies for particle network microstructure quantification. Evidence is found that relates flocculation to the progressive relaxation of shear-induced anisotropy of the carbon black micro dispersion.
{"title":"EFFECTS OF SHEAR HISTORY ON THE MECHANICAL, ELECTRICAL, AND MICROSTRUCTURAL PROPERTIES OF PARTICLE-REINFORCED RUBBER","authors":"L. Tunnicliffe, Seth L. Young","doi":"10.5254/rct-d-23-00026","DOIUrl":"https://doi.org/10.5254/rct-d-23-00026","url":null,"abstract":"\u0000 The extent and nature of networks of carbon black particles in rubber compounds play a key role in determining the mechanical hysteresis and conductivity of rubber goods. It is well known that in uncrosslinked compounds, such networks display transient and time-dependent behavior when subjected to steps or ramps in shear and temperature (often called flocculation). This study probes the observed structural recoveries of carbon black networks following various levels of imposed shear strain histories. It is demonstrated that the level of shear experienced by the compound immediately before vulcanization can have a dramatic effect on the final dynamic mechanical properties of the subsequently vulcanized materials. Significant reductions in Payne effect occur when the timescales of shear-induced structural recovery, determined from rheological experiments, exceed the kinetics of vulcanization. Electrical conductivity/resistivity is also affected, especially for compounds formulated in the electrical percolation transition region. Furthermore, the microstructure of carbon black networks is tracked at different extents of recovery by using transmission electron microscopy thin section analysis and atomic force microscopy methodologies for particle network microstructure quantification. Evidence is found that relates flocculation to the progressive relaxation of shear-induced anisotropy of the carbon black micro dispersion.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48267210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seyed Mostaffa Hosseini, H. Najjarzadeh, M. Razzaghi‐Kashani, Alireza Baniasad
Development of green tires by using silica and silane in tread compounds has emerged as a key technology in the tire industry. One of the most important features of a green tire is its low rolling resistance; however, agreement between other performances of a tire, such as wet grip and wear, along with rolling resistance of tread compounds, is a serious challenge. Properties of tire tread compounds are very sensitive to the silanization of silica and the loading of primary and secondary fillers. This work investigates simultaneous effects of silanization of silica as the primary filler and loading of carbon black as the secondary filler. By performing dynamic-mechanical testing in strain sweep and mechanical testing of tire tread compounds, the degree of silanization of silica and loading of carbon black were tuned to make agreement between friction, abrasion, and rolling resistance of green tire tread compounds. Morphology of the filler, kinetics of vulcanization, and bound rubber content in the tread compounds were used to explain the findings. Other than dynamic-mechanical analyses to predict final performance of tread compounds, direct measurements of friction, abrasion, and rolling resistance of tread compounds showed a 43% increase in the coefficient of friction on wet concrete, a 47% increase in abrasion resistance, and a rolling resistance coefficient of approximately 6.5 by using 10 parts per hundred of rubber (phr) of bis(triethoxysilylpropyl)tetrasulfide and 10 phr of carbon black N330 as the secondary filler.
{"title":"AGREEMENT BETWEEN FRICTION, ABRASION, AND ROLLING RESISTANCE IN SILICA-FILLED TIRE TREAD COMPOUNDS BY TUNING DEGREE OF SILANIZATION AND LOADING OF CARBON BLACK","authors":"Seyed Mostaffa Hosseini, H. Najjarzadeh, M. Razzaghi‐Kashani, Alireza Baniasad","doi":"10.5254/rct-d-23-00019","DOIUrl":"https://doi.org/10.5254/rct-d-23-00019","url":null,"abstract":"\u0000 Development of green tires by using silica and silane in tread compounds has emerged as a key technology in the tire industry. One of the most important features of a green tire is its low rolling resistance; however, agreement between other performances of a tire, such as wet grip and wear, along with rolling resistance of tread compounds, is a serious challenge. Properties of tire tread compounds are very sensitive to the silanization of silica and the loading of primary and secondary fillers. This work investigates simultaneous effects of silanization of silica as the primary filler and loading of carbon black as the secondary filler. By performing dynamic-mechanical testing in strain sweep and mechanical testing of tire tread compounds, the degree of silanization of silica and loading of carbon black were tuned to make agreement between friction, abrasion, and rolling resistance of green tire tread compounds. Morphology of the filler, kinetics of vulcanization, and bound rubber content in the tread compounds were used to explain the findings. Other than dynamic-mechanical analyses to predict final performance of tread compounds, direct measurements of friction, abrasion, and rolling resistance of tread compounds showed a 43% increase in the coefficient of friction on wet concrete, a 47% increase in abrasion resistance, and a rolling resistance coefficient of approximately 6.5 by using 10 parts per hundred of rubber (phr) of bis(triethoxysilylpropyl)tetrasulfide and 10 phr of carbon black N330 as the secondary filler.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49251107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yinping Tao, Ryuichi Tashiro, Shigeki Yonezawa, Christopher A. Stevens, Emiliano Bilotti, James J.C. Busfield
Abstract: Cord-rubber composites such as timing belts are subjected to coupled tension and bending under typical service conditions. Due to its increased modulus, carbon cords are replacing the traditional glass cords as the reinforcing materials in timing belt products. The bending fatigue behaviour of carbon cord reinforced hydrogenated butadiene rubber (CC-HNBR) composites is of increasing interest for both understanding their failure mechanism and supporting new industrial product development. In this work, a simple experimental set-up that replicated in a simplified way the real-pulley situation encountered in a timing belt operation was developed, in order to investigate the effects of the applied tension, bending curvature, frequency and R ratio on the bending fatigue life of carbon cord reinforced hydrogenated nitrile butadiene rubber (CC-HNBR) composites. Furthermore, numerical investigation of the stress distribution within the CC-HNBR composite, under both uniaxial tension and coupled tension and bending loading, were carried out using finite element analysis (FEA). Cord-dominated fracture was observed close to the point where the specimen just left the pulley using a thermal imaging camera at high stress levels. This location is due to the combined effects of bending and maximum tension at this site. There was a reduction in the bending fatigue life as a result of a higher level of bending strain introduced by a smaller diameter pulley. Frequency had negligible effects on the bending fatigue life within testing regimes probably resulting from the rubber only generating limited heat build-up even at the highest test frequencies. Higher R ratios led to a longer bending fatigue life potentially because of strain induced crystallisation of the HNBR matrix at the tip of any cracks that are generated. This study provides a basic investigation into the bending fatigue behaviour of CC-HNBR composites under coupled tension and bending loading conditions, shedding some light on failure characteristics of CC-HNBR composites under interaction of bending and tension deformations.
{"title":"Quasi-static bending fatigue of carbon cord-rubber composites used in timing belts","authors":"Yinping Tao, Ryuichi Tashiro, Shigeki Yonezawa, Christopher A. Stevens, Emiliano Bilotti, James J.C. Busfield","doi":"10.5254/rct.23.76985","DOIUrl":"https://doi.org/10.5254/rct.23.76985","url":null,"abstract":"Abstract: Cord-rubber composites such as timing belts are subjected to coupled tension and bending under typical service conditions. Due to its increased modulus, carbon cords are replacing the traditional glass cords as the reinforcing materials in timing belt products. The bending fatigue behaviour of carbon cord reinforced hydrogenated butadiene rubber (CC-HNBR) composites is of increasing interest for both understanding their failure mechanism and supporting new industrial product development. In this work, a simple experimental set-up that replicated in a simplified way the real-pulley situation encountered in a timing belt operation was developed, in order to investigate the effects of the applied tension, bending curvature, frequency and R ratio on the bending fatigue life of carbon cord reinforced hydrogenated nitrile butadiene rubber (CC-HNBR) composites. Furthermore, numerical investigation of the stress distribution within the CC-HNBR composite, under both uniaxial tension and coupled tension and bending loading, were carried out using finite element analysis (FEA). Cord-dominated fracture was observed close to the point where the specimen just left the pulley using a thermal imaging camera at high stress levels. This location is due to the combined effects of bending and maximum tension at this site. There was a reduction in the bending fatigue life as a result of a higher level of bending strain introduced by a smaller diameter pulley. Frequency had negligible effects on the bending fatigue life within testing regimes probably resulting from the rubber only generating limited heat build-up even at the highest test frequencies. Higher R ratios led to a longer bending fatigue life potentially because of strain induced crystallisation of the HNBR matrix at the tip of any cracks that are generated. This study provides a basic investigation into the bending fatigue behaviour of CC-HNBR composites under coupled tension and bending loading conditions, shedding some light on failure characteristics of CC-HNBR composites under interaction of bending and tension deformations.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135444404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT A new three-dimensional tire REF (ring on elastic foundation) model in rolling contact has been proposed and verified in this paper. The motivation is to apply this new physical model to the three-dimensional forces estimation for intelligent tires, which is currently a research hotspot in the automotive industry. The core contribution is the analytical solution of the three-dimensional tire deformation, stress, and forces in complex rolling contact. This new physical model is universal and efficient in linking intelligent tire signals with the solution results, which provides a powerful theoretical tool for intelligent tire modeling. Furthermore, the results have been validated by sensitivity analysis of key structural parameters on tire performance. In summary, through the modeling, verification, and application in case studies, it has been shown that the proposed methodology can be used for real practical three-dimensional forces estimation, which has the potential to simplify the vehicle state observer and benefit autonomous vehicles.
{"title":"A THREE-DIMENSIONAL TIRE REF MODEL IN ROLLING CONTACT WITH APPLICATION TO INTELLIGENT TIRES","authors":"Delei Min, Yintao Wei","doi":"10.5254/rct.23.76981","DOIUrl":"https://doi.org/10.5254/rct.23.76981","url":null,"abstract":"ABSTRACT A new three-dimensional tire REF (ring on elastic foundation) model in rolling contact has been proposed and verified in this paper. The motivation is to apply this new physical model to the three-dimensional forces estimation for intelligent tires, which is currently a research hotspot in the automotive industry. The core contribution is the analytical solution of the three-dimensional tire deformation, stress, and forces in complex rolling contact. This new physical model is universal and efficient in linking intelligent tire signals with the solution results, which provides a powerful theoretical tool for intelligent tire modeling. Furthermore, the results have been validated by sensitivity analysis of key structural parameters on tire performance. In summary, through the modeling, verification, and application in case studies, it has been shown that the proposed methodology can be used for real practical three-dimensional forces estimation, which has the potential to simplify the vehicle state observer and benefit autonomous vehicles.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135444403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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