Guangchang Wu, Paul Sotta, Menglong Huang, Lewis B Tunnicliffe, James JC Busfield
ABSTRACT Smear wear behavior has often been observed during rubber abrasion, especially under mild test severities. It generates degraded sticky rubber debris that often produces erratic measurements of abrasion weight loss. Various practical methods to avoid or remove the debris from the abrasion test surface have been reported, such as applying a drying powder lubricant. However, the detailed mechanism of smear wear behavior is still not clear. Various characterization techniques are applied to investigate the smear wear of both an unfilled NR model compound and a commercial carbon black (CB)–filled SBR tire tread compound obtained during blade abrasion testing. The debris showed lower molecular weight and higher oxygen content than the virgin materials. In addition, 75% of the smear wear was found to be de-crosslinked during smear wear, as detected by the double quantum-NMR technique. For the first time, it is demonstrated that both the polymer itself and crosslinking points are broken down during smear wear. The effect of the smear layer on friction and abrasion is also discussed.
{"title":"Characterisation of Sticky Debris Generated During Smear Wear","authors":"Guangchang Wu, Paul Sotta, Menglong Huang, Lewis B Tunnicliffe, James JC Busfield","doi":"10.5254/rct-23.236012","DOIUrl":"https://doi.org/10.5254/rct-23.236012","url":null,"abstract":"ABSTRACT Smear wear behavior has often been observed during rubber abrasion, especially under mild test severities. It generates degraded sticky rubber debris that often produces erratic measurements of abrasion weight loss. Various practical methods to avoid or remove the debris from the abrasion test surface have been reported, such as applying a drying powder lubricant. However, the detailed mechanism of smear wear behavior is still not clear. Various characterization techniques are applied to investigate the smear wear of both an unfilled NR model compound and a commercial carbon black (CB)–filled SBR tire tread compound obtained during blade abrasion testing. The debris showed lower molecular weight and higher oxygen content than the virgin materials. In addition, 75% of the smear wear was found to be de-crosslinked during smear wear, as detected by the double quantum-NMR technique. For the first time, it is demonstrated that both the polymer itself and crosslinking points are broken down during smear wear. The effect of the smear layer on friction and abrasion is also discussed.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135432008","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}
Léna Costecalde, Adrien Leygue, Michel Coret, Erwan Verron
This paper presents a novel method for accurately identifying the large strain elastic response of elastomeric materials. The method combines the Data-Driven Identification (DDI) algorithm with a unique heterogeneous experiment, deviating from the conventional approach of conducting multiple simple experiments. The primary objective of the method is to decouple the experimental process from the fitting technique, relying instead on a single comprehensive experiment to generate an extensive collection of stress and strain energy fields. This collection is then utilized in conjunction with a standard fitting technique to determine the parameters of hyperelastic models. Notably, the approach places significant emphasis on the strain energy density field as a critical factor in model identification, as it encompasses the full material response within a single scalar quantity. To demonstrate the effectiveness of the proposed approach, a proofof-concept is provided using synthetic data. The results highlight the efficiency of the method and emphasize the importance of incorporating the strain energy density field for precise model identification, surpassing the reliance on stress data alone. Additionally, the paper introduces several graphical tools to evaluate and analyze the quality of both the generated mechanical fields and the identification results. The proposed approach offers a more comprehensive representation of the material behavior, and enhances the reliability and prediction capabilities of hyperelastic material models. It holds significant potential for advancing the field of solid mechanics, particularly in accurately characterizing the mechanical responses of elastomeric materials.
{"title":"Data-Driven Identification of hyperelastic models by measuring the strain energy density field","authors":"Léna Costecalde, Adrien Leygue, Michel Coret, Erwan Verron","doi":"10.5254/rct-23.386903","DOIUrl":"https://doi.org/10.5254/rct-23.386903","url":null,"abstract":"This paper presents a novel method for accurately identifying the large strain elastic response of elastomeric materials. The method combines the Data-Driven Identification (DDI) algorithm with a unique heterogeneous experiment, deviating from the conventional approach of conducting multiple simple experiments. The primary objective of the method is to decouple the experimental process from the fitting technique, relying instead on a single comprehensive experiment to generate an extensive collection of stress and strain energy fields. This collection is then utilized in conjunction with a standard fitting technique to determine the parameters of hyperelastic models. Notably, the approach places significant emphasis on the strain energy density field as a critical factor in model identification, as it encompasses the full material response within a single scalar quantity. To demonstrate the effectiveness of the proposed approach, a proofof-concept is provided using synthetic data. The results highlight the efficiency of the method and emphasize the importance of incorporating the strain energy density field for precise model identification, surpassing the reliance on stress data alone. Additionally, the paper introduces several graphical tools to evaluate and analyze the quality of both the generated mechanical fields and the identification results. The proposed approach offers a more comprehensive representation of the material behavior, and enhances the reliability and prediction capabilities of hyperelastic material models. It holds significant potential for advancing the field of solid mechanics, particularly in accurately characterizing the mechanical responses of elastomeric materials.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135216563","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}
Decades of elastomeric fracture phenomenology due to Thomas and Smith demonstrated a remarkable fact that rubbers are stronger and tougher at lower temperatures. The prevailing explanation relates the fracture behavior to polymer viscoelasticity. Given the recent insight and evidence that toughness is determined by strength, we examine elastomeric fracture with a different perspective and conclude that chain scission dictates fracture characteristics including its temperature dependence. Working within a selected temperature range, stretching is shown to be entirely elastic at stretching rate below 0.17 s-1, we demonstrate that the same temperature and rate dependencies of strength and toughness, observed by Thomas and Smith, still occur in our crosslinked polybutadiene (BR) and styrene-butadiene rubber (SBR). The temperature effects on rate dependence of strength and toughness are found to be much stronger than that prescribed by the WLF shift factor aT. Moreover, crack propagates, upon either stepwise stretching or during creep, at a much lower speed at lower temperature that cannot be rationalized with polymer relaxation dynamics. Our new interpretation is that a carbon-carbon bond is stronger at a lower temperature, equivalently, it takes a longer time for a covalent bond to undergo dissociation in tension because available thermal energy is proportional to temperature T.
{"title":"Investigating dependence of elastomeric fracture on temperature and rate","authors":"Shi-Qing Wang, Zehao Fan","doi":"10.5254/rct-23.033084","DOIUrl":"https://doi.org/10.5254/rct-23.033084","url":null,"abstract":"Decades of elastomeric fracture phenomenology due to Thomas and Smith demonstrated a remarkable fact that rubbers are stronger and tougher at lower temperatures. The prevailing explanation relates the fracture behavior to polymer viscoelasticity. Given the recent insight and evidence that toughness is determined by strength, we examine elastomeric fracture with a different perspective and conclude that chain scission dictates fracture characteristics including its temperature dependence. Working within a selected temperature range, stretching is shown to be entirely elastic at stretching rate below 0.17 s-1, we demonstrate that the same temperature and rate dependencies of strength and toughness, observed by Thomas and Smith, still occur in our crosslinked polybutadiene (BR) and styrene-butadiene rubber (SBR). The temperature effects on rate dependence of strength and toughness are found to be much stronger than that prescribed by the WLF shift factor aT. Moreover, crack propagates, upon either stepwise stretching or during creep, at a much lower speed at lower temperature that cannot be rationalized with polymer relaxation dynamics. Our new interpretation is that a carbon-carbon bond is stronger at a lower temperature, equivalently, it takes a longer time for a covalent bond to undergo dissociation in tension because available thermal energy is proportional to temperature T.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569691","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}
Lewis B. Tunnicliffe, Christopher G. Robertson, William V. Mars
Tensile stress-strain testing is used to investigate fracture behavior of carbon black-reinforced styrene-butadiene rubber, using 50 replicate specimens. Four vulcanized rubber compounds are studied: a CB-filled SBR with standard mixing conditions (Control); the same formulation with intentional poor mixing of the CB; and materials identical to the control material but formed by adding minor amounts of 0.5 mm diameter glass microspheres (beads) – serving as large model defects/inclusions - using a two-roll mill at two levels corresponding to average values of 0.78 and 6.24 beads per gauge section region of the tensile test specimen. This paper focuses on microscopy analysis of the resulting fracture surfaces to complement our recent publication on Weibull failure statistics for distributions of tensile strength and crack precursor size (Polymers 12, 203 (2020)). All 200 fractured specimens from tensile testing at 23°C are imaged with light microscopy and exhibit fracture surfaces that are characterized by relatively smooth planes that are perpendicular to the uniaxial loading direction. The majority of tensile failures originate from the edges of the dumbbell specimens, in line with expectations from fracture mechanics. Light microscopy reveals concentric fracture ring features of high specular reflectance emanating from crack precursors, which are a universal feature of the failure process for these compounds and independent of precursor type, size, or location. Non-contact interferometric microscopy confirms that the rings are the result of variations in surface micro-roughness; proceeding outwards from the precursor as rough-smooth-rough to the edge of the fracture surface. Fracture rings are also observed for tensile tests performed at 80°C. The variation in surface roughness of the fracture surface has parallels to the stick-slip tearing behavior seen for rubbers torn at medium to high rates. To the best of the authors’ knowledge, this is the first time that such striking features have been reported.
{"title":"A MICROSCOPY INVESTIGATION OF RUBBER COMPOUND CRACK PRECURSORS AND TENSILE FRACTURE SURFACES","authors":"Lewis B. Tunnicliffe, Christopher G. Robertson, William V. Mars","doi":"10.5254/rct-23.201163","DOIUrl":"https://doi.org/10.5254/rct-23.201163","url":null,"abstract":"Tensile stress-strain testing is used to investigate fracture behavior of carbon black-reinforced styrene-butadiene rubber, using 50 replicate specimens. Four vulcanized rubber compounds are studied: a CB-filled SBR with standard mixing conditions (Control); the same formulation with intentional poor mixing of the CB; and materials identical to the control material but formed by adding minor amounts of 0.5 mm diameter glass microspheres (beads) – serving as large model defects/inclusions - using a two-roll mill at two levels corresponding to average values of 0.78 and 6.24 beads per gauge section region of the tensile test specimen. This paper focuses on microscopy analysis of the resulting fracture surfaces to complement our recent publication on Weibull failure statistics for distributions of tensile strength and crack precursor size (Polymers 12, 203 (2020)). All 200 fractured specimens from tensile testing at 23°C are imaged with light microscopy and exhibit fracture surfaces that are characterized by relatively smooth planes that are perpendicular to the uniaxial loading direction. The majority of tensile failures originate from the edges of the dumbbell specimens, in line with expectations from fracture mechanics. Light microscopy reveals concentric fracture ring features of high specular reflectance emanating from crack precursors, which are a universal feature of the failure process for these compounds and independent of precursor type, size, or location. Non-contact interferometric microscopy confirms that the rings are the result of variations in surface micro-roughness; proceeding outwards from the precursor as rough-smooth-rough to the edge of the fracture surface. Fracture rings are also observed for tensile tests performed at 80°C. The variation in surface roughness of the fracture surface has parallels to the stick-slip tearing behavior seen for rubbers torn at medium to high rates. To the best of the authors’ knowledge, this is the first time that such striking features have been reported.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135858710","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}
Lion Sundermann, Benjamin Klie, Heike Wittek, Thomas Ebel, Kathrin Ottink, Ulrich Giese
ABSTRACT Rubber-based polymers with high carbon black content can be three-dimensionally (3D) printed using the additive manufacturing of elastomers process. However, high-viscosity materials limit printing resolution, making it difficult to produce fine structures and high-precision parts, especially two-component (2K) parts. The viscosity of a rubber compound used for rod seal applications was reduced and adjusted using Nipol® 1312 liquid rubber and the alkyl sulfonic phenyl ester Mesamoll® II as plasticizers to lower the torque level during extrusion when a reduced nozzle diameter of 0.4 mm is used in 3D printing. In addition, the flowability of the compound was enhanced prior to vulcanization of the part, which could increase the layer–layer bond and thus reduce the mechanical anisotropy typically induced by fused filament fabrication. Using a viscosity-optimized rubber compound, a 2K rod seal consisting of a thermoplastic polyurethane with elastomeric properties and an acrylonitrile rubber-based O-ring was produced and dynamically tested for leakage.
{"title":"Influence of the Mixture Viscosity on Mechanical Anisotropy and Processability of an NBR-Based Rubber Mixture for Additive Manufacturing","authors":"Lion Sundermann, Benjamin Klie, Heike Wittek, Thomas Ebel, Kathrin Ottink, Ulrich Giese","doi":"10.5254/rct-23.228315","DOIUrl":"https://doi.org/10.5254/rct-23.228315","url":null,"abstract":"ABSTRACT Rubber-based polymers with high carbon black content can be three-dimensionally (3D) printed using the additive manufacturing of elastomers process. However, high-viscosity materials limit printing resolution, making it difficult to produce fine structures and high-precision parts, especially two-component (2K) parts. The viscosity of a rubber compound used for rod seal applications was reduced and adjusted using Nipol® 1312 liquid rubber and the alkyl sulfonic phenyl ester Mesamoll® II as plasticizers to lower the torque level during extrusion when a reduced nozzle diameter of 0.4 mm is used in 3D printing. In addition, the flowability of the compound was enhanced prior to vulcanization of the part, which could increase the layer–layer bond and thus reduce the mechanical anisotropy typically induced by fused filament fabrication. Using a viscosity-optimized rubber compound, a 2K rod seal consisting of a thermoplastic polyurethane with elastomeric properties and an acrylonitrile rubber-based O-ring was produced and dynamically tested for leakage.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136057958","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}
Thomas Berger, Sangro Park, Wonhyuck Lee, Michael Kaliske
ABSTRACT Tires are the only contact points between vehicle and road and are mainly responsible for the driving safety. In the recent past, two different classes of friction formulations are predominant. Phenomenological approaches formulate a mathematical expression to describe the experimental results. By knowledge and experience, the formulations interpolate and extrapolate the behaviour captured by experiments. However, the formulations are highly dependent on the quality of the experiments and its influence factors. Therefore, a second class of friction models have been introduced, micromechanical approaches. The friction kinematics is described based on the deformation of the rubber in the contact zone, while sliding over a generalized surface. The basic idea is to obtain the friction coefficient solely by the surface properties and the material behaviour. As both approaches have advantages and disadvantages, it is hard to distinguish, which is more suitable to use in a certain application. In this contribution, different friction formulations are discussed and compared to each other. The mechanical behaviour of rubber is strongly influenced by temperature and so are its friction characteristics. Therefore, the friction formulations are expanded with respect to temperature. The discussed temperature dependent friction formulations are compared to each other for tire cornering simulations. The decrease of the cornering stiffness at large slip angles can be explained by friction induced temperature increase in the contact zone.
{"title":"A comparison of phenomenlogical and micromechanical friction formulations including temperature effects","authors":"Thomas Berger, Sangro Park, Wonhyuck Lee, Michael Kaliske","doi":"10.5254/rct-23.461877","DOIUrl":"https://doi.org/10.5254/rct-23.461877","url":null,"abstract":"ABSTRACT Tires are the only contact points between vehicle and road and are mainly responsible for the driving safety. In the recent past, two different classes of friction formulations are predominant. Phenomenological approaches formulate a mathematical expression to describe the experimental results. By knowledge and experience, the formulations interpolate and extrapolate the behaviour captured by experiments. However, the formulations are highly dependent on the quality of the experiments and its influence factors. Therefore, a second class of friction models have been introduced, micromechanical approaches. The friction kinematics is described based on the deformation of the rubber in the contact zone, while sliding over a generalized surface. The basic idea is to obtain the friction coefficient solely by the surface properties and the material behaviour. As both approaches have advantages and disadvantages, it is hard to distinguish, which is more suitable to use in a certain application. In this contribution, different friction formulations are discussed and compared to each other. The mechanical behaviour of rubber is strongly influenced by temperature and so are its friction characteristics. Therefore, the friction formulations are expanded with respect to temperature. The discussed temperature dependent friction formulations are compared to each other for tire cornering simulations. The decrease of the cornering stiffness at large slip angles can be explained by friction induced temperature increase in the contact zone.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136293508","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}
To develop a technologically compatible blend of NR and NBR is always a challenge due to their polarity mismatch. As a result, the physico-mechanical properties of their blends are generally poor. To address this issue, an attempt was made to increase the uniform distribution of crosslinks across the blend phases at the time of molding at 170°C. A cure composition consisting of sulfur (S) and a delayed action accelerator (N-cyclohexyl-2-benzothiazole sulfenamide [CBS]) has been designed to co-crosslink both phases of the blend simultaneously. The tensile properties, particularly the tensile strength (TS) of the blend cured by this method, were superior (∼371% greater) than the TS of the blend cured using a combination of S/CBS and an ultrafast accelerator (tetramethylthiuram disulfide [TMTD]). A bifunctional maleimide (Maleide F) was also used in conjunction with S/CBS in the curing recipe to further improve the distribution of sulfidic crosslinks by reducing the interfacial tension between the NR and NBR phases via Alder-ene reaction.
{"title":"IMPROVING THE PROPERTIES OF NR/NBR BLEND BY INTRODUCING INTERFACIAL CROSSLINKS USING BISMALEIMIDE DURING THE INITIAL PHASE OF ACCELERATED SULFUR CURING","authors":"M. Pöschl, S. G. Sathi, R. Stoček","doi":"10.5254/rct23.948326","DOIUrl":"https://doi.org/10.5254/rct23.948326","url":null,"abstract":"To develop a technologically compatible blend of NR and NBR is always a challenge due to their polarity mismatch. As a result, the physico-mechanical properties of their blends are generally poor. To address this issue, an attempt was made to increase the uniform distribution of crosslinks across the blend phases at the time of molding at 170°C. A cure composition consisting of sulfur (S) and a delayed action accelerator (N-cyclohexyl-2-benzothiazole sulfenamide [CBS]) has been designed to co-crosslink both phases of the blend simultaneously. The tensile properties, particularly the tensile strength (TS) of the blend cured by this method, were superior (∼371% greater) than the TS of the blend cured using a combination of S/CBS and an ultrafast accelerator (tetramethylthiuram disulfide [TMTD]). A bifunctional maleimide (Maleide F) was also used in conjunction with S/CBS in the curing recipe to further improve the distribution of sulfidic crosslinks by reducing the interfacial tension between the NR and NBR phases via Alder-ene reaction.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139327999","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 To develop a technologically compatible blend of natural rubber (NR) and acrylonitrile-co-butadiene rubber (NBR) is always a challenge due to their polarity mismatch. As a result, the physico-mechanical properties of their blends will be generally poor. To address this issue, an attempt was made to increase the uniform distribution of crosslinks across the blend phases at the time of molding at 170 °C. A cure composition consisting of sulfur (S) and a delayed-action accelerator (N-cyclohexyl-2-benzothiazole sulfenamide: CBS) has been designed to co-crosslink both phases of the blend simultaneously. The tensile properties, particularly the tensile strength (TS) of the blend cured by this method were superior (approximately 371% greater) than the TS of the blend cured using a combination of S/CBS and an ultrafast accelerator (Tetramethylthiuram disulfide, TMTD). A bifunctional maleimide (Maleide F) was also employed in conjunction with S/CBS in the curing recipe to further improve the distribution of sulfidic crosslinks by reducing the interfacial tension between the NR and NBR phases via Alder-ene reaction.
{"title":"IMPROVING THE PROPERTIES OF A POLY (ACRYLONITRILE-CO-BUTADIENE)/NATURAL RUBBER BLEND BY INTRODUCING INTERFACIAL CROSSLINKS USING BISMALEIMIDE DURING THE INITIAL PHASE OF ACCELERATED SULFUR CURING","authors":"Marek Pöschl, Shibulal G. Sathi, Radek Stoček","doi":"10.5254/rct-23.948326","DOIUrl":"https://doi.org/10.5254/rct-23.948326","url":null,"abstract":"ABSTRACT To develop a technologically compatible blend of natural rubber (NR) and acrylonitrile-co-butadiene rubber (NBR) is always a challenge due to their polarity mismatch. As a result, the physico-mechanical properties of their blends will be generally poor. To address this issue, an attempt was made to increase the uniform distribution of crosslinks across the blend phases at the time of molding at 170 °C. A cure composition consisting of sulfur (S) and a delayed-action accelerator (N-cyclohexyl-2-benzothiazole sulfenamide: CBS) has been designed to co-crosslink both phases of the blend simultaneously. The tensile properties, particularly the tensile strength (TS) of the blend cured by this method were superior (approximately 371% greater) than the TS of the blend cured using a combination of S/CBS and an ultrafast accelerator (Tetramethylthiuram disulfide, TMTD). A bifunctional maleimide (Maleide F) was also employed in conjunction with S/CBS in the curing recipe to further improve the distribution of sulfidic crosslinks by reducing the interfacial tension between the NR and NBR phases via Alder-ene reaction.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246441","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 The phenomenon of damage observed in cord-rubber composite laminates is the result of deformation, heat, chemical damage and fracture. The micro cracks and the initial voids, present before any load is applied, grow through the mechanism of coalescence and generate permanent macroscopic cracks. A damage approach is proposed to describe the cumulative effects and damage evolution under cyclic loading, thermal and chemical impact. The approach parallels the Continuum Damage Mechanics (CDM) approach advocated by Kachanov and Rabotnov (ref.1, 2) It is a phenomenological model which depends on laboratory testing to describe the evolution of damage and contains one scalar parameter to describe the collective effect of material damage. The following analysis is based on the premise that the cyclic interlaminar shear strain, coupled with the running temperature at the free edge is the primary cause of damage. The model constants were derived from an S-N curve at room temperature. The temperature effect on the material damage was accounted for by an Arrhenius shift function of the S-N curve. Numerical simulation of a composite laminate was conducted using the user subroutine UMAT in ABAQUS. The results presented reflect the accuracy of the proposed methodology to predict the location of the ensuing damage, and the path of the damage propagation.
{"title":"Analysis of Cord-Rubber Composite Response Using the Nonlinear Continuum Damage Mechanics Approach","authors":"Mahmoud C Assaad, Ming Du, Tom Ebbott","doi":"10.5254/rct-23.361055","DOIUrl":"https://doi.org/10.5254/rct-23.361055","url":null,"abstract":"ABSTRACT The phenomenon of damage observed in cord-rubber composite laminates is the result of deformation, heat, chemical damage and fracture. The micro cracks and the initial voids, present before any load is applied, grow through the mechanism of coalescence and generate permanent macroscopic cracks. A damage approach is proposed to describe the cumulative effects and damage evolution under cyclic loading, thermal and chemical impact. The approach parallels the Continuum Damage Mechanics (CDM) approach advocated by Kachanov and Rabotnov (ref.1, 2) It is a phenomenological model which depends on laboratory testing to describe the evolution of damage and contains one scalar parameter to describe the collective effect of material damage. The following analysis is based on the premise that the cyclic interlaminar shear strain, coupled with the running temperature at the free edge is the primary cause of damage. The model constants were derived from an S-N curve at room temperature. The temperature effect on the material damage was accounted for by an Arrhenius shift function of the S-N curve. Numerical simulation of a composite laminate was conducted using the user subroutine UMAT in ABAQUS. The results presented reflect the accuracy of the proposed methodology to predict the location of the ensuing damage, and the path of the damage propagation.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135245927","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}
Gina Butuc, Jose Swart, Marcel Simons, Jan van Velde, Kees van Leerdam, Brenda Rossenaar, Auke Talma, Anke Blume
ABSTRACT Sulfur donors are used commonly in rubber crosslinking, usually in conjunction with elemental sulfur. In the crosslinking process, sulfur donors release in-situ free sulfur. This study analyses the difference between two sulfur donors, bis(triethoxysilylpropyl)- tetrasulfide (TESPT) and cyclic tetrasulfide (CTS), both containing at least one tetrasulfidic group in the molecule. Chemical model studies are deployed to assess the chemical reactivity of the two molecules. The difference in reactivity of the two sulfur donors was observed in chemical model studies in reaction with 2,3-dimethyl-2-butene, as followed by Raman Spectroscopy, GC-MS and NMR analysis of the products of reaction. These studies represent a fundamental analysis and comparison between the two tetrasulfidic compounds and the findings of these experiments can be extrapolated to crosslinking processes in rubber.
{"title":"A fundamental study on Cyclic Tetrasulfide (CTS) as a sulfur donor and co-agent for rubber crosslinking","authors":"Gina Butuc, Jose Swart, Marcel Simons, Jan van Velde, Kees van Leerdam, Brenda Rossenaar, Auke Talma, Anke Blume","doi":"10.5254/rct-23.158368","DOIUrl":"https://doi.org/10.5254/rct-23.158368","url":null,"abstract":"ABSTRACT Sulfur donors are used commonly in rubber crosslinking, usually in conjunction with elemental sulfur. In the crosslinking process, sulfur donors release in-situ free sulfur. This study analyses the difference between two sulfur donors, bis(triethoxysilylpropyl)- tetrasulfide (TESPT) and cyclic tetrasulfide (CTS), both containing at least one tetrasulfidic group in the molecule. Chemical model studies are deployed to assess the chemical reactivity of the two molecules. The difference in reactivity of the two sulfur donors was observed in chemical model studies in reaction with 2,3-dimethyl-2-butene, as followed by Raman Spectroscopy, GC-MS and NMR analysis of the products of reaction. These studies represent a fundamental analysis and comparison between the two tetrasulfidic compounds and the findings of these experiments can be extrapolated to crosslinking processes in rubber.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246063","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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