D. Penumadu, Jun-Cheng Chin, Stephen Young, F. Ignatz-Hoover, T. R. Floyd, Peter Chapman
Good dispersion of compounded ingredients in a rubber formulation is important for mechanical performance. After mixing, certain materials can remain undispersed within the rubber matrix, which could lead to critical flaws, influencing performance according to the Griffith failure criteria. High resolution X-ray computed tomography (XCT) offers a unique opportunity to measure phase domain size and distributions. Fillers such as carbon black or silica can be differentiated from sulfur or zinc oxide, providing an opportunity to determine dispersion characteristics of the various phases. The XCT technique has become an important characterization tool for three-dimensional and higher dimension material science due to the availability of polychromatic micro-focus x-ray sources and efficient high spatial resolution detectors with superior scintillators. High resolution XCT provides very rich data quantifying mixing efficiency of particulates in a matrix, such as insoluble sulfur or silica particles in rubber. Imaging with X-rays provides attenuation, phase, or scattering contrast and will prove to be a critical method for evaluating the field of rubber crosslinking, considering realistic environments in situ. This paper highlights methodology development and validation and provides insight on the dispersion of polymeric (insoluble) sulfur in rubber formulations. Dispersion assessment is compared using three techniques: high resolution XCT, population survival analysis in tensile testing, and optical microscopy.
{"title":"SULFUR DISPERSION QUANTITATIVE ANALYSIS IN ELASTOMERIC TIRE FORMULATIONS BY USING HIGH RESOLUTION X-RAY COMPUTED TOMOGRAPHY","authors":"D. Penumadu, Jun-Cheng Chin, Stephen Young, F. Ignatz-Hoover, T. R. Floyd, Peter Chapman","doi":"10.5254/rct.21.79997","DOIUrl":"https://doi.org/10.5254/rct.21.79997","url":null,"abstract":"\u0000 Good dispersion of compounded ingredients in a rubber formulation is important for mechanical performance. After mixing, certain materials can remain undispersed within the rubber matrix, which could lead to critical flaws, influencing performance according to the Griffith failure criteria. High resolution X-ray computed tomography (XCT) offers a unique opportunity to measure phase domain size and distributions. Fillers such as carbon black or silica can be differentiated from sulfur or zinc oxide, providing an opportunity to determine dispersion characteristics of the various phases. The XCT technique has become an important characterization tool for three-dimensional and higher dimension material science due to the availability of polychromatic micro-focus x-ray sources and efficient high spatial resolution detectors with superior scintillators. High resolution XCT provides very rich data quantifying mixing efficiency of particulates in a matrix, such as insoluble sulfur or silica particles in rubber. Imaging with X-rays provides attenuation, phase, or scattering contrast and will prove to be a critical method for evaluating the field of rubber crosslinking, considering realistic environments in situ. This paper highlights methodology development and validation and provides insight on the dispersion of polymeric (insoluble) sulfur in rubber formulations. Dispersion assessment is compared using three techniques: high resolution XCT, population survival analysis in tensile testing, and optical microscopy.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42670487","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}
K. Roy, S. Debnath, D. Basu, Aphiwat Pongwisuthiruchte, P. Potiyaraj
In recent years, the application of sol-gel science to industrial polymer research has offered advancements in rubber technology. The use of sol-gel–synthesized materials for the development of highly reinforced rubber composites is the most commonly adopted and popular method exercised by rubber scientists. This article comprehensively reviews the recent progress regarding preparation and properties of sol-gel–synthesized nanoparticles-based rubber composites. The pragmatic consequences of sol-gel–synthesized nanoparticles in rubber compounds are systematically described through rheological, mechanical, and thermal properties. Emphatic focus is given to understanding the reinforcement mechanism of rubber composites by the use of sol-gel–derived alkoxide silica as filler. The properties of rubber nanocomposites are usually dependent on the dispersion of sol-gel–synthesized nanoparticles into the rubber matrix. The results reviewed from prolific studies suggested that sol-gel science has tremendous potential to develop high performance rubber nanocomposites for future industrial application.
{"title":"EMERGING ADVANCES IN RUBBER TECHNOLOGY BY THE SUITABLE APPLICATION OF SOL-GEL SCIENCE AND TECHNOLOGY","authors":"K. Roy, S. Debnath, D. Basu, Aphiwat Pongwisuthiruchte, P. Potiyaraj","doi":"10.5254/rct.21.79955","DOIUrl":"https://doi.org/10.5254/rct.21.79955","url":null,"abstract":"\u0000 In recent years, the application of sol-gel science to industrial polymer research has offered advancements in rubber technology. The use of sol-gel–synthesized materials for the development of highly reinforced rubber composites is the most commonly adopted and popular method exercised by rubber scientists. This article comprehensively reviews the recent progress regarding preparation and properties of sol-gel–synthesized nanoparticles-based rubber composites. The pragmatic consequences of sol-gel–synthesized nanoparticles in rubber compounds are systematically described through rheological, mechanical, and thermal properties. Emphatic focus is given to understanding the reinforcement mechanism of rubber composites by the use of sol-gel–derived alkoxide silica as filler. The properties of rubber nanocomposites are usually dependent on the dispersion of sol-gel–synthesized nanoparticles into the rubber matrix. The results reviewed from prolific studies suggested that sol-gel science has tremendous potential to develop high performance rubber nanocomposites for future industrial application.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48568126","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}
A. Gannoruwa, Yuanbing Zhou, Kenichiro Kosugi, Yoshimasa Yamamoto, S. Kawahara
The origin of energetic elasticity in conjunction with the entropic elasticity for natural rubber with a nanodiamond nanomatrix structure was investigated in terms of bound rubber formed between nanodiamonds, based on the interaction between natural rubber and nanodiamonds inside the nanomatrix. The natural rubber with a nanodiamond nanomatrix structure was prepared by reacting nanodiamonds with deproteinized natural rubber in the presence of tert-butylhydroperoxide/tetraethylenepentamine at 30 °C in the latex stage followed by drying. Morphology of the products was observed by two-dimensional and three-dimensional transmission electron microscopies. The effect of bound rubber on the mechanical properties of the products was investigated by measurements of the dynamic mechanical properties and differential scanning calorimetry. The contribution of bound rubber was estimated by combining the Takayanagi equation and modified Guth–Gold equation. A significant increase in complex modulus was attributed to the effect of the bound rubber.
{"title":"ORIGIN OF ENERGETIC ELASTICITY AND ENTROPIC ELASTICITY OF NATURAL RUBBER WITH NANODIAMOND NANOMATRIX STRUCTURE","authors":"A. Gannoruwa, Yuanbing Zhou, Kenichiro Kosugi, Yoshimasa Yamamoto, S. Kawahara","doi":"10.5254/rct.21.79923","DOIUrl":"https://doi.org/10.5254/rct.21.79923","url":null,"abstract":"\u0000 The origin of energetic elasticity in conjunction with the entropic elasticity for natural rubber with a nanodiamond nanomatrix structure was investigated in terms of bound rubber formed between nanodiamonds, based on the interaction between natural rubber and nanodiamonds inside the nanomatrix. The natural rubber with a nanodiamond nanomatrix structure was prepared by reacting nanodiamonds with deproteinized natural rubber in the presence of tert-butylhydroperoxide/tetraethylenepentamine at 30 °C in the latex stage followed by drying. Morphology of the products was observed by two-dimensional and three-dimensional transmission electron microscopies. The effect of bound rubber on the mechanical properties of the products was investigated by measurements of the dynamic mechanical properties and differential scanning calorimetry. The contribution of bound rubber was estimated by combining the Takayanagi equation and modified Guth–Gold equation. A significant increase in complex modulus was attributed to the effect of the bound rubber.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48723795","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}
We develop an ex situ technique to quantitatively analyze the transport properties of hydrogen gas dissolved under high pressure in rubbery polymers, such as cylindrical and spherical samples of nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM), which are potential sealing materials for hydrogen energy infrastructures. The technique consists of real-time gravimetric measurements during the desorption of hydrogen gas from samples using an electronic balance and a self-developed analysis program to determine the total charge (CH0), diffusivity (D), solubility (S) and permeability (P) of hydrogen. Dual absorption behavior is found for all three rubbers as the charging pressure increases. CH0 follows Henry's law at low pressures of up to ∼25 MPa, whereas the Langmuir model applies at high pressures. No significant pressure, size, or shape dependences are observed for D and P. The measured P values are consistent with those from the literature within the combined uncertainty evaluated. The effect of a carbon black filler mixed into rubber is discussed with respect to S and D. This method can be applicable as a standard test for the transport properties versus the pressure of various polymers irrespective of sample shape.
{"title":"CHARACTERIZING THE HYDROGEN TRANSPORT PROPERTIES OF RUBBERY POLYMERS BY GRAVIMETRIC ANALYSIS","authors":"J. Jung, In Gyoo Kim, S. K. Jeon, K. Chung","doi":"10.5254/rct.21.79880","DOIUrl":"https://doi.org/10.5254/rct.21.79880","url":null,"abstract":"\u0000 We develop an ex situ technique to quantitatively analyze the transport properties of hydrogen gas dissolved under high pressure in rubbery polymers, such as cylindrical and spherical samples of nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM), which are potential sealing materials for hydrogen energy infrastructures. The technique consists of real-time gravimetric measurements during the desorption of hydrogen gas from samples using an electronic balance and a self-developed analysis program to determine the total charge (CH0), diffusivity (D), solubility (S) and permeability (P) of hydrogen. Dual absorption behavior is found for all three rubbers as the charging pressure increases. CH0 follows Henry's law at low pressures of up to ∼25 MPa, whereas the Langmuir model applies at high pressures. No significant pressure, size, or shape dependences are observed for D and P. The measured P values are consistent with those from the literature within the combined uncertainty evaluated. The effect of a carbon black filler mixed into rubber is discussed with respect to S and D. This method can be applicable as a standard test for the transport properties versus the pressure of various polymers irrespective of sample shape.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44610409","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}
Unsaturated chain structure of natural rubber makes it a poor defense against thermo-oxidative aging. Synthetic antioxidants are commonly used in rubber compound recipes to prevent/retard aging of the rubber material during its service life. However, synthetic antioxidants cause some negative effects on human and environmental health; they tend to be replaced by natural alternatives. In this study, the short- and long-term antioxidant effects of henna and its basic active components, lawsone and gallic acid, have been investigated individually for natural rubber cured with semi-efficient sulfur vulcanization system. The composition of henna was determined by gas chromatography-mass spectrometry (GC-MS) analysis. Qualitative and quantitative analysis were performed using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to highlight structural changes on aged vulcanizates. The authors attempted to correlate the suggested aging mechanism with rheological, mechanical, and morphological properties. Results showed that both lawsone and gallic acid were impressively successful regarding their anti-oxidation activity. In addition, henna, which contains a sufficient amount of lawsone and gallic acid, has been suggested as a competitive natural alternative to the common synthetic stabilization system for natural rubber, considering its sustainable commercial abundancy.
{"title":"POTENTIAL SUSTAINABLE ANTIOXIDANTS FOR NATURAL RUBBER: HENNA AND ITS MAJOR COMPONENTS","authors":"Şehriban Öncel, A. A. Wis, B. Karaağaç","doi":"10.5254/rct.21.79907","DOIUrl":"https://doi.org/10.5254/rct.21.79907","url":null,"abstract":"\u0000 Unsaturated chain structure of natural rubber makes it a poor defense against thermo-oxidative aging. Synthetic antioxidants are commonly used in rubber compound recipes to prevent/retard aging of the rubber material during its service life. However, synthetic antioxidants cause some negative effects on human and environmental health; they tend to be replaced by natural alternatives. In this study, the short- and long-term antioxidant effects of henna and its basic active components, lawsone and gallic acid, have been investigated individually for natural rubber cured with semi-efficient sulfur vulcanization system. The composition of henna was determined by gas chromatography-mass spectrometry (GC-MS) analysis. Qualitative and quantitative analysis were performed using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to highlight structural changes on aged vulcanizates. The authors attempted to correlate the suggested aging mechanism with rheological, mechanical, and morphological properties. Results showed that both lawsone and gallic acid were impressively successful regarding their anti-oxidation activity. In addition, henna, which contains a sufficient amount of lawsone and gallic acid, has been suggested as a competitive natural alternative to the common synthetic stabilization system for natural rubber, considering its sustainable commercial abundancy.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42340018","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}
Yayoi Akahori, M. Hiza, Soki Yamaguchi, S. Kawahara
Protein effect on vulcanization of NR, obtained from Hevea brasiliensis, was investigated by analyzing the crosslinking structure of the resulting vulcanizates prepared from untreated NR, deproteinized natural rubber (DPNR), and protein-free natural rubber (PFNR) by swelling methods and rubber-state NMR spectroscopy. The proteins present in NR were removed by three methods: deproteinization with enzyme, urea, or urea–acetone in the presence of sodium dodecyl sulfate. The amount of proteins present in NR, approximately 0.238 w/w%, was reduced to 0.000 w/w% by urea–acetone deproteinization, whereas it was reduced to approximately 0.003 and 0.019 w/w% by enzyme and urea deproteinizations, respectively. Hardness, swelling degree, and crosslinking structure depended on the amount of proteins. Changes in mechanical properties for the vulcanizates prepared from not only non-filler compounds but also carbon black–filled and silica-filled compounds were attributed to the amount of proteins.
{"title":"PROTEIN INFLUENCE ON THE MECHANICAL PROPERTIES OF NR","authors":"Yayoi Akahori, M. Hiza, Soki Yamaguchi, S. Kawahara","doi":"10.5254/rct.21.79916","DOIUrl":"https://doi.org/10.5254/rct.21.79916","url":null,"abstract":"\u0000 Protein effect on vulcanization of NR, obtained from Hevea brasiliensis, was investigated by analyzing the crosslinking structure of the resulting vulcanizates prepared from untreated NR, deproteinized natural rubber (DPNR), and protein-free natural rubber (PFNR) by swelling methods and rubber-state NMR spectroscopy. The proteins present in NR were removed by three methods: deproteinization with enzyme, urea, or urea–acetone in the presence of sodium dodecyl sulfate. The amount of proteins present in NR, approximately 0.238 w/w%, was reduced to 0.000 w/w% by urea–acetone deproteinization, whereas it was reduced to approximately 0.003 and 0.019 w/w% by enzyme and urea deproteinizations, respectively. Hardness, swelling degree, and crosslinking structure depended on the amount of proteins. Changes in mechanical properties for the vulcanizates prepared from not only non-filler compounds but also carbon black–filled and silica-filled compounds were attributed to the amount of proteins.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43084239","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}
J. Joseph, T. K. Sreethu, S. Mohanty, V. K. Gupta, A. Bhowmick
To the best of our knowledge, for the first time, metal-organic framework (MOF), a porous reticular structure, has been tried as a reinforcing filler for rubber. A MOF synthesized by solvothermal reaction between 2-aminoterephthalic acid and aluminum chloride hexahydrate was characterized and incorporated as reinforcing filler in SBR. A comparative investigation on the properties of the well-dispersed, thermally stable nano-MOF composite (SBR-MOF) was carried out with reference to SBR–nano alumina composite (SBR-nAl). The SBR-MOF was mechanically more robust than SBR-nAl. The SBR-MOF showed 130% improvement in tensile strength over the pristine SBR composite and 50% better elongation at break than SBR-nAl at 10 phr loading. The thermal and dynamic mechanical properties of SBR-MOF are superior to SBR-nAl composite. The highly porous organic framework was favorable for the enhanced entanglement of polymer chains at the interface. The effectiveness of the organic framework on the dispersion and compatibility was evaluated by scanning electron microscopy. The dispersion studies substantially supported the overall property enhancement. To substantiate the superiority of MOF in the rubber matrix, the tensile properties of SBR-MOF were compared with SBR composites filled with nano silica, nano titania, as well as nano silica and nano alumina with a compatibilizer, thereby documenting a promising nanofiller for introduction into the rubber industry.
{"title":"METAL-ORGANIC FRAMEWORK: A SMART REPLACEMENT FOR CONVENTIONAL NANOFILLERS FOR THE ENHANCEMENT OF MECHANICAL PROPERTIES AND THERMAL STABILITY OF SBR NANOCOMPOSITE","authors":"J. Joseph, T. K. Sreethu, S. Mohanty, V. K. Gupta, A. Bhowmick","doi":"10.5254/rct.21.79903","DOIUrl":"https://doi.org/10.5254/rct.21.79903","url":null,"abstract":"\u0000 To the best of our knowledge, for the first time, metal-organic framework (MOF), a porous reticular structure, has been tried as a reinforcing filler for rubber. A MOF synthesized by solvothermal reaction between 2-aminoterephthalic acid and aluminum chloride hexahydrate was characterized and incorporated as reinforcing filler in SBR. A comparative investigation on the properties of the well-dispersed, thermally stable nano-MOF composite (SBR-MOF) was carried out with reference to SBR–nano alumina composite (SBR-nAl). The SBR-MOF was mechanically more robust than SBR-nAl. The SBR-MOF showed 130% improvement in tensile strength over the pristine SBR composite and 50% better elongation at break than SBR-nAl at 10 phr loading. The thermal and dynamic mechanical properties of SBR-MOF are superior to SBR-nAl composite. The highly porous organic framework was favorable for the enhanced entanglement of polymer chains at the interface. The effectiveness of the organic framework on the dispersion and compatibility was evaluated by scanning electron microscopy. The dispersion studies substantially supported the overall property enhancement. To substantiate the superiority of MOF in the rubber matrix, the tensile properties of SBR-MOF were compared with SBR composites filled with nano silica, nano titania, as well as nano silica and nano alumina with a compatibilizer, thereby documenting a promising nanofiller for introduction into the rubber industry.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49538193","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}
Butadiene rubber (BR) is one of the most useful and second most produced rubber worldwide. Polymerization of 1,3-butadiene (BD) is a highly stereospecific reaction that offers a wide variety of BR with different microstructures and influences the fundamental properties of the rubber. Since the first successful polymerization of conjugated diene using the Ziegler–Natta–based catalyst (TiCl4 or TiCl3 with aluminum alkyls) in 1954, the research on producing synthetic rubber with an appropriate catalyst system has been accelerated. Subsequently, various research groups are actively engaged in designing active catalyst systems based on a suitable combination of transition metal complexes with alkyl-aluminum and successfully using them in BD polymerization. Although various scientific inventions have proven their significance for the production of high-quality BR, with the rising demands in improving the quality of the product, research on developing new catalyst systems with enhanced catalytic activity and high stereoselectivity is still in progress. The present review focuses on the synthesis of BR using various transition metal catalysts and discusses their microstructures. The catalysts based on new-generation metal complexes with phosphorus, nitrogen, and oxygen donor ligands (e.g., phosphines, imines, 1,10-phenanthroline, and imino-pyridines) have been introduced. The role that catalysts play in the production of BR with different microstructures (i.e., high-cis, high-trans or low-cis, low-trans polybutadiene) has also been described. The combination of catalyst (transition metal complex) and suitable co-catalyst (alkyl-aluminum) is the major factor influencing the reaction and microstructure of the resulting polymer. This report focuses on the effect of transition metal catalysts (i.e., lithium [Li], titanium [Ti], zirconium [Zr], iron [Fe], cobalt [Co], nickel [Ni], and neodymium [Nd]) on the activity and stereoselectivity of polymers such as 1,4-cis-, 1,4-trans-, and 1,2-vinyl-polybutadiene.
{"title":"BUTADIENE RUBBER: SYNTHESIS, MICROSTRUCTURE, AND ROLE OF CATALYSTS","authors":"Ajay Kumar, S. Mohanty, Virendrakumar Gupta","doi":"10.5254/rct.21.79948","DOIUrl":"https://doi.org/10.5254/rct.21.79948","url":null,"abstract":"\u0000 Butadiene rubber (BR) is one of the most useful and second most produced rubber worldwide. Polymerization of 1,3-butadiene (BD) is a highly stereospecific reaction that offers a wide variety of BR with different microstructures and influences the fundamental properties of the rubber. Since the first successful polymerization of conjugated diene using the Ziegler–Natta–based catalyst (TiCl4 or TiCl3 with aluminum alkyls) in 1954, the research on producing synthetic rubber with an appropriate catalyst system has been accelerated. Subsequently, various research groups are actively engaged in designing active catalyst systems based on a suitable combination of transition metal complexes with alkyl-aluminum and successfully using them in BD polymerization. Although various scientific inventions have proven their significance for the production of high-quality BR, with the rising demands in improving the quality of the product, research on developing new catalyst systems with enhanced catalytic activity and high stereoselectivity is still in progress. The present review focuses on the synthesis of BR using various transition metal catalysts and discusses their microstructures. The catalysts based on new-generation metal complexes with phosphorus, nitrogen, and oxygen donor ligands (e.g., phosphines, imines, 1,10-phenanthroline, and imino-pyridines) have been introduced. The role that catalysts play in the production of BR with different microstructures (i.e., high-cis, high-trans or low-cis, low-trans polybutadiene) has also been described. The combination of catalyst (transition metal complex) and suitable co-catalyst (alkyl-aluminum) is the major factor influencing the reaction and microstructure of the resulting polymer. This report focuses on the effect of transition metal catalysts (i.e., lithium [Li], titanium [Ti], zirconium [Zr], iron [Fe], cobalt [Co], nickel [Ni], and neodymium [Nd]) on the activity and stereoselectivity of polymers such as 1,4-cis-, 1,4-trans-, and 1,2-vinyl-polybutadiene.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44156745","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}
Najib Alam, Vineet Kumar, S. Ryu, Tae Jo Koa, Dong‐Joo Lee, Jungwook Choi
This article presents the development of a new kind of magnetorheological elastomer blend made with natural rubber, acrylonitrile–butadiene rubber (NR-NBR), and electrolytic iron particles through solution mixing. The compressive stress and elastic modulus of the composites in the isotropic and anisotropic states of the filler were studied. A unique study of the filler distribution and filler orientation mechanism was proposed from the compressive properties and scanning electron microscopy. A strong improvement in the elastic modulus of the NR–NBR blend from isotropic to anisotropic change was achieved as compared with NR and NBR in single-rubber composites. The filler content in the anisotropic magnetorheological elastomers was optimized by measuring the field-dependent elastic modulus in the presence of an externally applied magnetic field. The blend rubber composites showed better sensitivity in the presence of a magnetic field than the NR and NBR composites did. The improvement might be due to the better filler orientation and strong adhesion of filler particles by the NR phase in the blend matrix. The new elastomer blends may have applications in active dampers, vibrational absorption, and automotive bushings.
{"title":"SYNERGISTIC MAGNETORHEOLOGICAL NR–NBR ELASTOMER BLEND WITH ELECTROLYTIC IRON PARTICLES","authors":"Najib Alam, Vineet Kumar, S. Ryu, Tae Jo Koa, Dong‐Joo Lee, Jungwook Choi","doi":"10.5254/rct.21.79977","DOIUrl":"https://doi.org/10.5254/rct.21.79977","url":null,"abstract":"\u0000 This article presents the development of a new kind of magnetorheological elastomer blend made with natural rubber, acrylonitrile–butadiene rubber (NR-NBR), and electrolytic iron particles through solution mixing. The compressive stress and elastic modulus of the composites in the isotropic and anisotropic states of the filler were studied. A unique study of the filler distribution and filler orientation mechanism was proposed from the compressive properties and scanning electron microscopy. A strong improvement in the elastic modulus of the NR–NBR blend from isotropic to anisotropic change was achieved as compared with NR and NBR in single-rubber composites. The filler content in the anisotropic magnetorheological elastomers was optimized by measuring the field-dependent elastic modulus in the presence of an externally applied magnetic field. The blend rubber composites showed better sensitivity in the presence of a magnetic field than the NR and NBR composites did. The improvement might be due to the better filler orientation and strong adhesion of filler particles by the NR phase in the blend matrix. The new elastomer blends may have applications in active dampers, vibrational absorption, and automotive bushings.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46579604","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}
Butadiene rubbers are frequently produced through solution polymerizations using Ziegler–Natta catalysts based on neodymium. Particularly, there is great interest in developing rubbers that present enhanced processability during the formulation step. For this reason, the present work investigated the production of butadiene rubbers in the presence of polar additives, such as methyl methacrylate, methacrylic acid, and water, through solution polymerizations, using neodymium versatate as catalyst. The obtained results confirmed the possibility of producing butadiene rubbers with polar character that presented improved processability properties during the vulcanization stage. In addition, a new use for water and the manufacture of copolymers of butadiene and oxygenated monomers in polymerization processes that make use of neodymium catalysts are reported for the first time.
{"title":"POLAR ADDITIVES IN 1,3-BUTADIENE POLYMERIZATION","authors":"M. Vasconcelos, M. Nele, J. Pinto","doi":"10.5254/rct.21.79933","DOIUrl":"https://doi.org/10.5254/rct.21.79933","url":null,"abstract":"\u0000 Butadiene rubbers are frequently produced through solution polymerizations using Ziegler–Natta catalysts based on neodymium. Particularly, there is great interest in developing rubbers that present enhanced processability during the formulation step. For this reason, the present work investigated the production of butadiene rubbers in the presence of polar additives, such as methyl methacrylate, methacrylic acid, and water, through solution polymerizations, using neodymium versatate as catalyst. The obtained results confirmed the possibility of producing butadiene rubbers with polar character that presented improved processability properties during the vulcanization stage. In addition, a new use for water and the manufacture of copolymers of butadiene and oxygenated monomers in polymerization processes that make use of neodymium catalysts are reported for the first time.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48946214","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：