Butyl and bromobutyl inner tubes, specified by the Aerospace Standard AS50141 for military aircraft, were thermally aged from 40 to 120 °C for varying lengths of time and then their hardness and mechanical properties were measured. 1H double quantum nuclear magnetic resonance (DQ NMR) was used to elucidate crosslink density and distribution changes. Time–temperature superposition of the aged data coupled with the Arrhenius approach was used to determine an approximate shelf life. High (80–120 °C) and low (40–80 °C) temperature oxidation processes were occurring for both rubbers. Below 80 °C, an increase in crosslink density, hardening, stiffening, and loss of elongation was observed. Plasticizer and volatile loss contributes to compound stiffening. Sulfur crosslink network modifications during thermal aging can explain ultimate property loss and stiffness increase. Diffusion limited oxidation was taking place above 80 °C, with the development of a thin oxidized layer composed of ionic crosslinking that affected both hardness and mechanical properties. For butyl rubber, the hardness rise stabilizes as do the ultimate properties, likely due to the proliferation of chain scission reactions, whereas crosslinking reactions prevailed over chain scission events for bromobutyl rubber. Crosslink density and defect fractions B and C as measured through DQ NMR were in agreement with the physical property testing results. The degree of heterogeneity of the network as perceived visually through DQ NMR regularization increases upon exposure to higher temperatures and longer aging times due to the broadening of the crosslink density distribution. Similar Arrhenius activation energies were calculated for the low and high temperature oxidation process for butyl and bromobutyl rubbers. The projected shelf life for the butyl and bromobutyl inner tubes was 10 and 20 yr, respectively. For the first time, DQ NMR testing results (crosslink density and its distribution, defect level) have been successfully applied to support a shelf life determination.
{"title":"Accelerated Heat Aging of Butyl and Bromobutyl Aircraft Inner Tubes for Shelf Life Determination","authors":"G. Germain, Na Li,, R. Pazur","doi":"10.5254/rct.22.78935","DOIUrl":"https://doi.org/10.5254/rct.22.78935","url":null,"abstract":"\u0000 Butyl and bromobutyl inner tubes, specified by the Aerospace Standard AS50141 for military aircraft, were thermally aged from 40 to 120 °C for varying lengths of time and then their hardness and mechanical properties were measured. 1H double quantum nuclear magnetic resonance (DQ NMR) was used to elucidate crosslink density and distribution changes. Time–temperature superposition of the aged data coupled with the Arrhenius approach was used to determine an approximate shelf life. High (80–120 °C) and low (40–80 °C) temperature oxidation processes were occurring for both rubbers. Below 80 °C, an increase in crosslink density, hardening, stiffening, and loss of elongation was observed. Plasticizer and volatile loss contributes to compound stiffening. Sulfur crosslink network modifications during thermal aging can explain ultimate property loss and stiffness increase. Diffusion limited oxidation was taking place above 80 °C, with the development of a thin oxidized layer composed of ionic crosslinking that affected both hardness and mechanical properties. For butyl rubber, the hardness rise stabilizes as do the ultimate properties, likely due to the proliferation of chain scission reactions, whereas crosslinking reactions prevailed over chain scission events for bromobutyl rubber. Crosslink density and defect fractions B and C as measured through DQ NMR were in agreement with the physical property testing results. The degree of heterogeneity of the network as perceived visually through DQ NMR regularization increases upon exposure to higher temperatures and longer aging times due to the broadening of the crosslink density distribution. Similar Arrhenius activation energies were calculated for the low and high temperature oxidation process for butyl and bromobutyl rubbers. The projected shelf life for the butyl and bromobutyl inner tubes was 10 and 20 yr, respectively. For the first time, DQ NMR testing results (crosslink density and its distribution, defect level) have been successfully applied to support a shelf life determination.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49340460","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}
M. De Sarkar, N. Fujii, Yasushi Abe, Yasuhiro Kamba, T. Sunada
Chloroprene rubber (CR) is one of the most versatile synthetic rubbers suitable for numerous industrial applications. For years, zinc oxide (ZnO) has been satisfactorily used as the vulcanization activator for CR, typically with organic accelerator(s). Ethylene thiourea (ETU) is the most widely used accelerator, offering the best balance between cost and performance in CR vulcanizates. Recently, the ZnO level in rubber compounds has become a pressing issue because of its harmful environmental impacts. ETU is classified as a substance of potentially serious health risks. It is therefore imperative to identify sustainable crosslinking additives for CR from both technical and commercial standpoints. The key purpose of this review is to collate the significant lines of technological advances made to identify proecological curative options for CR and update the information up to the current year. In preparation for this review, pertinent scholarly articles on the curing of CR, published in scientific journals mainly in the past two decades, were assessed. Since the scope of this review is to capture the significant technical efforts available in the public domain, the reference list is therefore not necessarily an exhaustive one. Reports dealing with proprietary chemicals or undisclosed technical strategies are beyond the purview of this review.
{"title":"QUEST FOR SUSTAINABLE CURATIVES FOR CHLOROPRENE RUBBER: A COMPREHENSIVE REVIEW","authors":"M. De Sarkar, N. Fujii, Yasushi Abe, Yasuhiro Kamba, T. Sunada","doi":"10.5254/rct.22.77981","DOIUrl":"https://doi.org/10.5254/rct.22.77981","url":null,"abstract":"\u0000 Chloroprene rubber (CR) is one of the most versatile synthetic rubbers suitable for numerous industrial applications. For years, zinc oxide (ZnO) has been satisfactorily used as the vulcanization activator for CR, typically with organic accelerator(s). Ethylene thiourea (ETU) is the most widely used accelerator, offering the best balance between cost and performance in CR vulcanizates. Recently, the ZnO level in rubber compounds has become a pressing issue because of its harmful environmental impacts. ETU is classified as a substance of potentially serious health risks. It is therefore imperative to identify sustainable crosslinking additives for CR from both technical and commercial standpoints. The key purpose of this review is to collate the significant lines of technological advances made to identify proecological curative options for CR and update the information up to the current year. In preparation for this review, pertinent scholarly articles on the curing of CR, published in scientific journals mainly in the past two decades, were assessed. Since the scope of this review is to capture the significant technical efforts available in the public domain, the reference list is therefore not necessarily an exhaustive one. Reports dealing with proprietary chemicals or undisclosed technical strategies are beyond the purview of this review.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45040063","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}
In this study, a phosphorus-containing flame retardant, polybis(4-hydroxypheyl)-2-(6-oxo-6-H-dibenzodibenzo [c,e][1,2] oxaphosphino-6-yl) methylene succinate (PHDO) was prepared by melt condensation between (6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)-p-oxide-butanedioic acid (DDP) and 1,4-benzene dimethanol (PXG). Then, Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (1H NMR) were used to characterize the structure of this novel additive. It was added to silicone rubber (SR) in different proportions, and the flame retardant properties together with tensile behaviors of the SR blends were investigated. Results showed that the thermal stability was improved and the burning rate was slowed down after addition of this novel flame retardant. Vertical burning test, cone calorimetric evaluation, and limited oxygen index (LOI) measurement of the samples revealed that the SR with 15 phr of PHDO owned the best flame retardant properties and may pass UL-94 V-0 grade. This improved flame retardant performance may be ascribed to the formation of dense carbon layers, which effectively prevented the surface oxidation and inhibited combustion of the silicone matrix.
以(6- h -二苯并[c,e][1,2]磷磷-6-基甲基)-对氧化物丁二酸(DDP)和1,4-苯二甲醇(PXG)为原料，采用熔融缩合法制备了含磷阻燃剂聚双(4-羟基)-2-(6-氧-6- h -二苯并二苯并二苯并并[c,e][1,2]磷磷-6-基)亚甲基琥珀酸(PHDO)。然后利用傅里叶变换红外光谱(FTIR)和氢核磁共振(1H NMR)对该添加剂的结构进行了表征。将其按不同比例添加到硅橡胶(SR)中，研究了共混物的阻燃性能和拉伸性能。结果表明，该新型阻燃剂的加入提高了材料的热稳定性，减缓了材料的燃烧速度。垂直燃烧试验、锥量热评价和限氧指数(LOI)测定结果表明，PHDO含量为15 phr的SR阻燃性能最好，可达到UL-94 V-0级。这种阻燃性能的提高可能是由于形成了致密的碳层，有效地防止了硅基的表面氧化和抑制了燃烧。
{"title":"DOPO-BASED FLAME RETARDANT: PREPARATION AND ITS APPLICATION IN SILICONE RUBBER BLENDS","authors":"Xu Mengyang, Liu Cheng, Wang Jincheng","doi":"10.5254/rct.22.78969","DOIUrl":"https://doi.org/10.5254/rct.22.78969","url":null,"abstract":"\u0000 In this study, a phosphorus-containing flame retardant, polybis(4-hydroxypheyl)-2-(6-oxo-6-H-dibenzodibenzo [c,e][1,2] oxaphosphino-6-yl) methylene succinate (PHDO) was prepared by melt condensation between (6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)-p-oxide-butanedioic acid (DDP) and 1,4-benzene dimethanol (PXG). Then, Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (1H NMR) were used to characterize the structure of this novel additive. It was added to silicone rubber (SR) in different proportions, and the flame retardant properties together with tensile behaviors of the SR blends were investigated. Results showed that the thermal stability was improved and the burning rate was slowed down after addition of this novel flame retardant. Vertical burning test, cone calorimetric evaluation, and limited oxygen index (LOI) measurement of the samples revealed that the SR with 15 phr of PHDO owned the best flame retardant properties and may pass UL-94 V-0 grade. This improved flame retardant performance may be ascribed to the formation of dense carbon layers, which effectively prevented the surface oxidation and inhibited combustion of the silicone matrix.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48184964","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}
Although the effects produced by the surface treatment of rubber with organic solvent solutions of trichloroisocyanuric acid (TCI) leading to improved adhesion to polyurethane (PU) adhesive have been established, the mechanism of adhesion involved is still unclear. In this study, the reaction of TCI species on the rubber surface with the polyurethane adhesive leading to the formation of chemical bonds was proposed as the relevant mechanism of adhesion. As a model, TCI was added to polyurethane adhesive (PU + TCI), and a polyurethane film was immersed in TCI solution (PU − TCI), their surface, structural, and viscoelastic properties were monitored for different times. The formation of chemical bonds between the polyurethane chains and TCI species derived from the solid TCI crystals on the rubber surface during bonding formation, and the crosslinking/hardening of the polyurethane surface were evidenced. The reaction with TCI species increased the surface energy on the polyurethane, mainly the polar component, similar surface energies were obtained in both PU + TCI and PU − TCI after 7 days. The enhanced surface energies on the PU that reacted with TCI were ascribed to the creation of new C–Cl and C=O species, their percentages were higher on PU + TCI than on PU − TCI surface. On the other hand, new N–H stretching and carbonyl species were produced; this indicated that TCI species interacted with the hard segments. Furthermore, the crystallization peaks in PU + TCI and PU − TCI at higher temperatures and lower enthalpies than in the PU indicated the disruption of the interactions between the soft segments. Therefore, the structural changes in the PU caused by reaction with TCI species affected their degree of phase separation and viscoelastic properties. The addition of solid TCI to the PU caused a noticeable degradation and hardening, the extent of degradation was more marked by increasing the time, this led to lower mechanical properties.
{"title":"DIFFERENT APPROACH TO THE MECHANISM OF ADHESION OF SURFACE TREATED WITH TRICHLOROISOCYANURIC ACID SOLUTION RUBBER AND POLYURETHANE ADHESIVE JOINTS","authors":"Verónica Pascual-Sánchez, J. Martín-Martínez","doi":"10.5254/rct.22.77974","DOIUrl":"https://doi.org/10.5254/rct.22.77974","url":null,"abstract":"\u0000 Although the effects produced by the surface treatment of rubber with organic solvent solutions of trichloroisocyanuric acid (TCI) leading to improved adhesion to polyurethane (PU) adhesive have been established, the mechanism of adhesion involved is still unclear. In this study, the reaction of TCI species on the rubber surface with the polyurethane adhesive leading to the formation of chemical bonds was proposed as the relevant mechanism of adhesion. As a model, TCI was added to polyurethane adhesive (PU + TCI), and a polyurethane film was immersed in TCI solution (PU − TCI), their surface, structural, and viscoelastic properties were monitored for different times. The formation of chemical bonds between the polyurethane chains and TCI species derived from the solid TCI crystals on the rubber surface during bonding formation, and the crosslinking/hardening of the polyurethane surface were evidenced. The reaction with TCI species increased the surface energy on the polyurethane, mainly the polar component, similar surface energies were obtained in both PU + TCI and PU − TCI after 7 days. The enhanced surface energies on the PU that reacted with TCI were ascribed to the creation of new C–Cl and C=O species, their percentages were higher on PU + TCI than on PU − TCI surface. On the other hand, new N–H stretching and carbonyl species were produced; this indicated that TCI species interacted with the hard segments. Furthermore, the crystallization peaks in PU + TCI and PU − TCI at higher temperatures and lower enthalpies than in the PU indicated the disruption of the interactions between the soft segments. Therefore, the structural changes in the PU caused by reaction with TCI species affected their degree of phase separation and viscoelastic properties. The addition of solid TCI to the PU caused a noticeable degradation and hardening, the extent of degradation was more marked by increasing the time, this led to lower mechanical properties.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43501559","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}
Milanta Tom, Sabu Thomas, B. Seantier, Y. Grohens, P. K. Mohamed, J. Haponiuk, Jaehwan Kim
Awareness of the environmental implications of conventional reinforcing fillers and the urge to reduce the carbon footprint have lead researchers to focus more on natural and sustainable materials. Nanocellulose from multitudinous sources finds use in elastomer engineering because of its distinctive properties, such as renewability, sustainability, abundance, biodegradability, high aspect ratio, excellent mechanical properties, and low cost. Green alternatives for conventional fillers in elastomer reinforcing have gained considerable interest to curb the risk of fillers from nonrenewable sources. The differences in properties of nanocellulose and elastomers render attractiveness in the search for synergistic properties resulting from their combination. This review addresses the isolation techniques for nanocellulose and challenges in its incorporation into the elastomer matrix. Surface modifications for solving incompatibility between filler and matrices are discussed. Processing of nanocomposites, various characterization techniques, mechanical behavior, and potential applications of nanocellulose elastomer composites are also discussed in detail.
{"title":"APPROACHING SUSTAINABILITY: NANOCELLULOSE REINFORCED ELASTOMERS—A REVIEW","authors":"Milanta Tom, Sabu Thomas, B. Seantier, Y. Grohens, P. K. Mohamed, J. Haponiuk, Jaehwan Kim","doi":"10.5254/rct.22.77013","DOIUrl":"https://doi.org/10.5254/rct.22.77013","url":null,"abstract":"\u0000 Awareness of the environmental implications of conventional reinforcing fillers and the urge to reduce the carbon footprint have lead researchers to focus more on natural and sustainable materials. Nanocellulose from multitudinous sources finds use in elastomer engineering because of its distinctive properties, such as renewability, sustainability, abundance, biodegradability, high aspect ratio, excellent mechanical properties, and low cost. Green alternatives for conventional fillers in elastomer reinforcing have gained considerable interest to curb the risk of fillers from nonrenewable sources. The differences in properties of nanocellulose and elastomers render attractiveness in the search for synergistic properties resulting from their combination. This review addresses the isolation techniques for nanocellulose and challenges in its incorporation into the elastomer matrix. Surface modifications for solving incompatibility between filler and matrices are discussed. Processing of nanocomposites, various characterization techniques, mechanical behavior, and potential applications of nanocellulose elastomer composites are also discussed in detail.\u0000","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45596772","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}
Iman Abbasi Shahdehi, M. Alimardani, M. Razzaghi‐Kashani, Hossein Roshanaei
The extent of modification of wet grip of tire tread rubber by safe aromatic process oils has been the subject of controversy, as this property has conventionally been judged by indirect methods such as the loss factor at 0 °C. The present work aims to directly measure the dry and wet frictional behavior of rubbers containing various loadings of distillate aromatic extract (DAE) or treated distillate aromatic extract (TDAE) and to elucidate the contributions resulting from the adhesion and the hysteretic terms of friction. Physico-mechanical tests including rubber hardness, rubber–substrate work of adhesion, rubber–oil compatibility, hysteretic properties, and the rubber glass transition temperature were evaluated to disclose the underlying friction mechanisms. Interestingly, TDAE-containing rubbers presented a comparable or even better hysteretic friction not only at low oil loadings but also at high oil levels. As the loss factor properties of DAE and TDAE are very close to each other and there is the possibility of a crossover point within the frictional zone, care must be exercised not to merely rely on the values of tanδ at 0 °C in judging the preference of DAE or TDAE with regard to the wet grip performance.
{"title":"ADHESION AND HYSTERETIC FRICTION OF TIRE TREAD RUBBERS HAVING PROCESS OILS WITH DIFFERENT AROMATIC CONTENT","authors":"Iman Abbasi Shahdehi, M. Alimardani, M. Razzaghi‐Kashani, Hossein Roshanaei","doi":"10.5254/rct.22.77937","DOIUrl":"https://doi.org/10.5254/rct.22.77937","url":null,"abstract":"\u0000 The extent of modification of wet grip of tire tread rubber by safe aromatic process oils has been the subject of controversy, as this property has conventionally been judged by indirect methods such as the loss factor at 0 °C. The present work aims to directly measure the dry and wet frictional behavior of rubbers containing various loadings of distillate aromatic extract (DAE) or treated distillate aromatic extract (TDAE) and to elucidate the contributions resulting from the adhesion and the hysteretic terms of friction. Physico-mechanical tests including rubber hardness, rubber–substrate work of adhesion, rubber–oil compatibility, hysteretic properties, and the rubber glass transition temperature were evaluated to disclose the underlying friction mechanisms. Interestingly, TDAE-containing rubbers presented a comparable or even better hysteretic friction not only at low oil loadings but also at high oil levels. As the loss factor properties of DAE and TDAE are very close to each other and there is the possibility of a crossover point within the frictional zone, care must be exercised not to merely rely on the values of tanδ at 0 °C in judging the preference of DAE or TDAE with regard to the wet grip performance.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42596487","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 nonlinear dynamic stiffness model of rolling-lobe air spring considering the Payne effect of the rubber diaphragm and the thermodynamic equivalent damping is proposed, with an aim to provide a theoretical basis for air spring structure design. A physical explanation and mathematical expression of each decoupled contribution term are given from the two dimensions of amplitude and frequency. An indicator test was designed to identify related parameters of the real and imaginary parts of dynamic stiffness. The results showed that the dynamic stiffness increases under a small excitation amplitude, verifying the correctness of the model considering the Payne effect. The influence of rubber diaphragm and gas terms is decoupled to separately illustrate the amplitude and frequency dependency of the real and imaginary parts of dynamic stiffness. A new evaluation index reflecting the contribution percentage of the rubber diaphragm is given, indicating that the stiffness of the rubber diaphragm at low amplitude cannot be ignored. In the end, the parameter influence and dynamic characteristics are provided so that the dynamic behavior of the rolling-lobe air spring can be predicted at the design stage. The proposed rolling-lobe air spring dynamic model considering the Payne effect of the rubber diaphragm provides guidance for the forward development and theoretical modeling of the air spring.
{"title":"INVESTIGATION OF THE NONLINEAR DYNAMIC STIFFNESS OF ROLLING-LOBE AIR SPRINGS CONSIDERING RUBBER PAYNE EFFECT","authors":"Mingyu Wu, Shiwei Wang, Hao Tong, Jing Wang, Hang Yin, Wenbo Zheng, Yaochao Li, Zhen Yu, Yintao Wei","doi":"10.5254/rct.22.77996","DOIUrl":"https://doi.org/10.5254/rct.22.77996","url":null,"abstract":"\u0000 A nonlinear dynamic stiffness model of rolling-lobe air spring considering the Payne effect of the rubber diaphragm and the thermodynamic equivalent damping is proposed, with an aim to provide a theoretical basis for air spring structure design. A physical explanation and mathematical expression of each decoupled contribution term are given from the two dimensions of amplitude and frequency. An indicator test was designed to identify related parameters of the real and imaginary parts of dynamic stiffness. The results showed that the dynamic stiffness increases under a small excitation amplitude, verifying the correctness of the model considering the Payne effect. The influence of rubber diaphragm and gas terms is decoupled to separately illustrate the amplitude and frequency dependency of the real and imaginary parts of dynamic stiffness. A new evaluation index reflecting the contribution percentage of the rubber diaphragm is given, indicating that the stiffness of the rubber diaphragm at low amplitude cannot be ignored. In the end, the parameter influence and dynamic characteristics are provided so that the dynamic behavior of the rolling-lobe air spring can be predicted at the design stage. The proposed rolling-lobe air spring dynamic model considering the Payne effect of the rubber diaphragm provides guidance for the forward development and theoretical modeling of the air spring.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42554627","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}
Chloroprene rubber (CR) vulcanizates have been widely used in various industrial applications due to their excellent mechanical properties such as elasticity, elongation at break, and superior resistance to chemicals, flame, etc. Because of the specific microstructures of CR, it is mainly vulcanized by metal oxide vulcanizing systems. However, CR undergoes rapid thermal degradation when it is crosslinked by peroxide curing systems at high temperatures. Although peroxide curing systems such as dicumyl peroxide (DCP) have attracted tremendous attention in the vulcanization of various saturated and unsaturated elastomers to achieve high-performance engineering properties, it is avoided for CR due to the occurrence of thermal decomposition, which is catalyzed by hydrochloric acid (HCl) vapors released during crosslinking. In the present work, by exploiting different acid acceptors, attempts have been made to design a vulcanizing system composed of inorganic–organic materials as acid acceptors to increase the potential of hindering the thermal decomposition in the CR phase. The designed system provides an accelerated system with a high crosslink density and mechanical properties comparable to metal oxide cured CR with elongation at break of ∼1000% and tensile strength of 10.3 MPa. The extent of thermal stabilization in the CR phase provided by the designed acid acceptor system was studied with thermogravimetric analysis.
{"title":"SYNERGIZED THERMAL STABILIZATION EFFECT OF ACID ACCEPTORS ON PEROXIDE CROSSLINKED CHLOROPRENE RUBBER","authors":"Zahra Shahroodi, A. Katbab","doi":"10.5254/rct.22.77945","DOIUrl":"https://doi.org/10.5254/rct.22.77945","url":null,"abstract":"\u0000 Chloroprene rubber (CR) vulcanizates have been widely used in various industrial applications due to their excellent mechanical properties such as elasticity, elongation at break, and superior resistance to chemicals, flame, etc. Because of the specific microstructures of CR, it is mainly vulcanized by metal oxide vulcanizing systems. However, CR undergoes rapid thermal degradation when it is crosslinked by peroxide curing systems at high temperatures. Although peroxide curing systems such as dicumyl peroxide (DCP) have attracted tremendous attention in the vulcanization of various saturated and unsaturated elastomers to achieve high-performance engineering properties, it is avoided for CR due to the occurrence of thermal decomposition, which is catalyzed by hydrochloric acid (HCl) vapors released during crosslinking. In the present work, by exploiting different acid acceptors, attempts have been made to design a vulcanizing system composed of inorganic–organic materials as acid acceptors to increase the potential of hindering the thermal decomposition in the CR phase. The designed system provides an accelerated system with a high crosslink density and mechanical properties comparable to metal oxide cured CR with elongation at break of ∼1000% and tensile strength of 10.3 MPa. The extent of thermal stabilization in the CR phase provided by the designed acid acceptor system was studied with thermogravimetric analysis.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44916907","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}
Sanghoon Song, Kiwon Hwang, Donghyuk Kim, Gyeongchan Ryu, B. Ahn, H. Jeon, S. Chung, Wonho Kim
Recently, considerable attention has been paid to the development of new functionalized polymers to improve the fuel efficiency of vehicles by reducing the rolling resistance of tires to adhere to strict CO2 emission regulations. Accordingly, multifunctionalized (MF) reversible addition–fragmentation chain transfer (RAFT) emulsion styrene–butadiene rubbers (ESBR) were synthesized, in which chain-end and in-chain functionalization were performed simultaneously by introducing a third monomer (glycidyl methacrylate; GMA) using RAFT polymerization. Compared with GMA ESBR, in which GMA is introduced as a third monomer by conventional radical polymerization (CRP), there was an even distribution of GMA per chain in the MF-RAFT ESBR. After preparing the silica-filled compounds, vulcanizate structure analysis and mechanical property evaluation of the compounds were performed. The MF-RAFT ESBR prepared by RAFT polymerization exhibited superior in-chain functionalization efficiency compared with GMA ESBR prepared by CRP because of the even distribution of GMA and higher crosslink density. Consequently, MF-RAFT ESBR compound showed superior silica dispersion, abrasion resistance, and lower rolling resistance compared with the GMA ESBR compound.
{"title":"EFFECTS OF EVEN FUNCTIONAL GROUP DISTRIBUTION IN EMULSION STYRENE–BUTADIENE RUBBER PREPARED BY REVERSIBLE ADDITION–FRAGMENTATION CHAIN TRANSFER POLYMERIZATION ON THE PROPERTIES OF SILICA-FILLED COMPOUNDS","authors":"Sanghoon Song, Kiwon Hwang, Donghyuk Kim, Gyeongchan Ryu, B. Ahn, H. Jeon, S. Chung, Wonho Kim","doi":"10.5254/rct.22.77993","DOIUrl":"https://doi.org/10.5254/rct.22.77993","url":null,"abstract":"\u0000 Recently, considerable attention has been paid to the development of new functionalized polymers to improve the fuel efficiency of vehicles by reducing the rolling resistance of tires to adhere to strict CO2 emission regulations. Accordingly, multifunctionalized (MF) reversible addition–fragmentation chain transfer (RAFT) emulsion styrene–butadiene rubbers (ESBR) were synthesized, in which chain-end and in-chain functionalization were performed simultaneously by introducing a third monomer (glycidyl methacrylate; GMA) using RAFT polymerization. Compared with GMA ESBR, in which GMA is introduced as a third monomer by conventional radical polymerization (CRP), there was an even distribution of GMA per chain in the MF-RAFT ESBR. After preparing the silica-filled compounds, vulcanizate structure analysis and mechanical property evaluation of the compounds were performed. The MF-RAFT ESBR prepared by RAFT polymerization exhibited superior in-chain functionalization efficiency compared with GMA ESBR prepared by CRP because of the even distribution of GMA and higher crosslink density. Consequently, MF-RAFT ESBR compound showed superior silica dispersion, abrasion resistance, and lower rolling resistance compared with the GMA ESBR compound.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44516085","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 rubber process analyzer was commercialized by Monsanto Rubber Instrument and Equipment company in the early 1990s. In its initial version, the RPA was able to perform only oscillatory-type tests, which varied in frequency and strain. Later, it offered a controlled strain–stress relaxation test. Only recently and not for all models has a controlled steady shear test been made available. Using this type of test, the instrument has successfully measured steady shear viscosity with high repeatability without correction. The results fit well with other rheometers or viscometers when no-slip conditions are ensured. The closed-boundary configuration prevents edge fracture, as commonly experienced with open-boundary rheometers (DMA) on high-viscosity, high-elasticity materials. A comparison of results using grooved dies (no-slip) and polished dies (slip) readily provides wall slip velocity under constant pressure. The results of wall slip versus shear stress follow a power-law function per the Navier slip law [F(V) = −k(Vr)e]. This method separates the shear rate from pressure effects on wall slip. It questions pressure-driven flow instruments (capillary rheometer), which use pressure measurements for shear stress calculations, and prevents an easy and controlled change of the die surface roughness.
{"title":"NEW AND HIGHLY EFFICIENT METHOD TO MEASURE STEADY SHEAR VISCOSITY AND WALL SLIP OF RUBBER COMPOUNDS: CLOSED-BOUNDARY RHEOMETER (RPA)","authors":"H. Burhin, Thomas Rauschmann, H. Graf","doi":"10.5254/rct.22.77929","DOIUrl":"https://doi.org/10.5254/rct.22.77929","url":null,"abstract":"\u0000 The rubber process analyzer was commercialized by Monsanto Rubber Instrument and Equipment company in the early 1990s. In its initial version, the RPA was able to perform only oscillatory-type tests, which varied in frequency and strain. Later, it offered a controlled strain–stress relaxation test. Only recently and not for all models has a controlled steady shear test been made available. Using this type of test, the instrument has successfully measured steady shear viscosity with high repeatability without correction. The results fit well with other rheometers or viscometers when no-slip conditions are ensured. The closed-boundary configuration prevents edge fracture, as commonly experienced with open-boundary rheometers (DMA) on high-viscosity, high-elasticity materials. A comparison of results using grooved dies (no-slip) and polished dies (slip) readily provides wall slip velocity under constant pressure. The results of wall slip versus shear stress follow a power-law function per the Navier slip law [F(V) = −k(Vr)e]. This method separates the shear rate from pressure effects on wall slip. It questions pressure-driven flow instruments (capillary rheometer), which use pressure measurements for shear stress calculations, and prevents an easy and controlled change of the die surface roughness.","PeriodicalId":21349,"journal":{"name":"Rubber Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45343906","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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