We read with great interest the recent article by Erenson(2023)entitled“Dispersion characteristics of clayey soils containing waste rubber particles”.The author has studied the dispersion characteristics of clayey s...We read with great interest the recent article by Erenson(2023)entitled“Dispersion characteristics of clayey soils containing waste rubber particles”.The author has studied the dispersion characteristics of clayey soils containing different percentages of waste rubber particles(WRPs)by performing several tests(viz.consistency limit,linear shrinkage limit,double hydrometer,crumb test and pinhole test)and scanning electron microscopy(SEM)analysis on five clayey(viz.Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin and Afyon clay)samples containing 0%,5%,10%and 15%WRPs.It should be noted that Erenson(2023)has presented some interesting observations,but there are some serious issues that we want to share through this discussion and request the author of the original paper to address them to avoid their persistence in the scientific literature.展开更多
The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity an...The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity and shear strength and to reduce the settlement and liquefaction potential of soils.The granular rubbers have many advantages such as temperature resistance,flexibility,tear-resistance,non-slip,and thermal and electrical insulation.This study presents the distribution characteristics of five different types of clayey soils with different engineering properties containing waste rubber particles(WRPs).On the other hand,determining and controlling the dispersion characteristics of clayey soils is two significant engineering problems.The study aims to solve these two remarkable and problematic issues in an eco-friendly and safe way.The role of WRP treatment in the investigation of soil dispersion behavior,which can cause dangerous problems such as piping,erosion,and dispersion,reflects the original and different perspectives of this study.Within this scope,geotechnical parameters of the clayey soils were determined.Subsequently,pinhole test,crumb test,double hydrometer test,and scanning electron microscopy(SEM)analysis were performed on the Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin,and Afyon clay samples with different percentages of WRPs(0%,5%,10%,and 15%).Consequently,Avanos and Ukrainian kaolin clays gave the most limited response to the dispersion behavior with the addition of WRP.Also,WRP treatment on the ball clay and bentonite samples showed limited efficiency.Afyon clay,which was defined as dispersive by the three tests that determined its dispersion potential,showed 3 level changes in the pinhole tests and 2 level changes in the crumb tests,and gave the most effective results in terms of WRP efficiency.展开更多
The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized ...The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.展开更多
~2H-NMR spectroscopy of the probe molecule,deuterated benzene,was applied to characterize organo-clay dispersion and confinement effect on the local motion of benzene in rubber/clay nanocomposite-gels.The observed ~2H...~2H-NMR spectroscopy of the probe molecule,deuterated benzene,was applied to characterize organo-clay dispersion and confinement effect on the local motion of benzene in rubber/clay nanocomposite-gels.The observed ~2H line shapes of benzene in intercalated and exfoliated nanocomposites were obviously different,which can be used to estimate clay-dispersion quality.~2H-NMR line shapes also reflect the different influence of intercalated or exfoliated layered-silicates on local motions of benzene,implying that...展开更多
Styrene-butadiene rubber(SBR)is widely used in tires in the automotive segment and vulcanization using sulfur is a common process to enhance its mechanical properties.However,the addition of sulfur as the cross-linkin...Styrene-butadiene rubber(SBR)is widely used in tires in the automotive segment and vulcanization using sulfur is a common process to enhance its mechanical properties.However,the addition of sulfur as the cross-linking agent usually results in impurities in pyrolysis products during rubber recycling,and thus the desulfurization during tire pyrolysis attracts much attention.In this work,the pyrolysis of vulcanized SBR is studied in detail with the help of Reax FF molecular dynamics simulation.A series of crosslinked SBR models were built with different sulfur contents and densities.The following Reax FF MD simulations were performed to show products distributions at different pyrolysis conditions.The simulation results show that sulfur products distribution is mainly controlled by sulfur contents and temperatures.The reaction mechanism is proposed based on the analysis of sulfur products conversion pathway,where most sulfur atoms are bonded with hydrocarbon radicals and the rest transfer to H_(2)S.High sulfur contents tend to the formation of elemental sulfur intermediate,and temperature increase facilitates the release of H_(2)S.展开更多
A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH)...A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH) was used as the interfacial modifier.The structure,morphology and mechanical properties of SBR/m-HNT nanocomposites,especially the interfacial interactions,were investigated.SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix at ...展开更多
Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental condit...Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental conditions.To surmount the limitations of conventional cross-linking modes,mechanical bonds stabilized by host-guest recognition are incorporated as the cross-linking points of SBR to form mechanically interlocked networks(MINs).Compared with covalently cross-linked network,the representative MIN exhibits superior mechanical performance in terms of elongation(1392%)and breaking strength(4.6 MPa),whose toughness has surged by 17 times.Dissociation of host-guest recognition and subsequent sliding motion provide an effective energy dissipation mechanism,and the release of hidden length is also beneficial to enhance toughness.Furthermore,the introduction of the rotaxane cross-links made the network more pliable and possess damping and elastic properties,which can return to initial state with one minute rest interval.We aspire that this direct introduction method can serve as a blueprint,offering valuable insights for the enhancement of mechanical properties in conventional commercial polymer materials.展开更多
The antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine(4010NA)was dissolved in ethanol and impregnated into silica aerogel(SAG)via vacuum-pressure cycles,yielding composite particles(A-N)with enhanced sustained-...The antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine(4010NA)was dissolved in ethanol and impregnated into silica aerogel(SAG)via vacuum-pressure cycles,yielding composite particles(A-N)with enhanced sustained-release and reinforcing capabilities.The effect of A-N on the mechanical properties and thermal-oxidative aging resistance of styrene-butadiene rubber(SBR)vulcanizates was investigated.TGA and BET assessments indicated that the loading efficiency of 4010NA in SAG reached 14.26%within ethanol's solu bility limit.Incorporating A-N into SBR vulcanizates significantly elevated tensile strength by 17.5%and elongation at break by 41.9%over those with fumed silica and free4010NA.Furthermore,A-N notably enhanced the thermal-oxidative aging resistance of SBR.After aging for 96 h at 100℃,the tensile strength and elongation at break of SBR with A-N sustained 70.09%and 58.61%of their initial values,respectively,with the retention rate of elongation at break being 62.8%higher than that of SBR with fumed silica and free antioxidant.The study revealed that A-N composite particles significantly inhibited the crosslinking in SBR's molecular chains,reducing hardening and embrittlement during later thermal-oxidative aging stages.展开更多
For the first time, this paper describes the concentration dependence of the relative dynamic viscosity coefficient of rubber suspensions and the initial viscoelastic modulus of 3D cross-linked elastomers on the maxim...For the first time, this paper describes the concentration dependence of the relative dynamic viscosity coefficient of rubber suspensions and the initial viscoelastic modulus of 3D cross-linked elastomers on the maximum volume filling with solid polydisperse particles. It allows to predict the rheological and mechanical properties of the polymer compositions being developed now. In this paper, we present the first experimental study of the pole of the concurrent lines of the concentration dependence in the coordinates of the linear form. The pole validates the invariant value of the constant of the developed equation and allows the experimental determination of the maximum volume filling of polymer binders filled with separate fractions or polydisperse mixtures. The results of the study are recommended for use in developing new polymer composite materials.展开更多
文摘We read with great interest the recent article by Erenson(2023)entitled“Dispersion characteristics of clayey soils containing waste rubber particles”.The author has studied the dispersion characteristics of clayey soils containing different percentages of waste rubber particles(WRPs)by performing several tests(viz.consistency limit,linear shrinkage limit,double hydrometer,crumb test and pinhole test)and scanning electron microscopy(SEM)analysis on five clayey(viz.Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin and Afyon clay)samples containing 0%,5%,10%and 15%WRPs.It should be noted that Erenson(2023)has presented some interesting observations,but there are some serious issues that we want to share through this discussion and request the author of the original paper to address them to avoid their persistence in the scientific literature.
基金supported by the Scientific Research Project of Aksaray University(Grant No.BAP-2021-31).
文摘The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity and shear strength and to reduce the settlement and liquefaction potential of soils.The granular rubbers have many advantages such as temperature resistance,flexibility,tear-resistance,non-slip,and thermal and electrical insulation.This study presents the distribution characteristics of five different types of clayey soils with different engineering properties containing waste rubber particles(WRPs).On the other hand,determining and controlling the dispersion characteristics of clayey soils is two significant engineering problems.The study aims to solve these two remarkable and problematic issues in an eco-friendly and safe way.The role of WRP treatment in the investigation of soil dispersion behavior,which can cause dangerous problems such as piping,erosion,and dispersion,reflects the original and different perspectives of this study.Within this scope,geotechnical parameters of the clayey soils were determined.Subsequently,pinhole test,crumb test,double hydrometer test,and scanning electron microscopy(SEM)analysis were performed on the Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin,and Afyon clay samples with different percentages of WRPs(0%,5%,10%,and 15%).Consequently,Avanos and Ukrainian kaolin clays gave the most limited response to the dispersion behavior with the addition of WRP.Also,WRP treatment on the ball clay and bentonite samples showed limited efficiency.Afyon clay,which was defined as dispersive by the three tests that determined its dispersion potential,showed 3 level changes in the pinhole tests and 2 level changes in the crumb tests,and gave the most effective results in terms of WRP efficiency.
文摘The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.
基金supported by the National Natural Science Foundation of China (Nos.20774054,20374031).
文摘~2H-NMR spectroscopy of the probe molecule,deuterated benzene,was applied to characterize organo-clay dispersion and confinement effect on the local motion of benzene in rubber/clay nanocomposite-gels.The observed ~2H line shapes of benzene in intercalated and exfoliated nanocomposites were obviously different,which can be used to estimate clay-dispersion quality.~2H-NMR line shapes also reflect the different influence of intercalated or exfoliated layered-silicates on local motions of benzene,implying that...
基金The authors would like to express appreciation for the support of National Key Research and Development Program of China(Grant No.2018YFC1902601).
文摘Styrene-butadiene rubber(SBR)is widely used in tires in the automotive segment and vulcanization using sulfur is a common process to enhance its mechanical properties.However,the addition of sulfur as the cross-linking agent usually results in impurities in pyrolysis products during rubber recycling,and thus the desulfurization during tire pyrolysis attracts much attention.In this work,the pyrolysis of vulcanized SBR is studied in detail with the help of Reax FF molecular dynamics simulation.A series of crosslinked SBR models were built with different sulfur contents and densities.The following Reax FF MD simulations were performed to show products distributions at different pyrolysis conditions.The simulation results show that sulfur products distribution is mainly controlled by sulfur contents and temperatures.The reaction mechanism is proposed based on the analysis of sulfur products conversion pathway,where most sulfur atoms are bonded with hydrocarbon radicals and the rest transfer to H_(2)S.High sulfur contents tend to the formation of elemental sulfur intermediate,and temperature increase facilitates the release of H_(2)S.
基金supported by the National Natural Science Foundation of China(Nos.50573021 and 50603005)
文摘A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH) was used as the interfacial modifier.The structure,morphology and mechanical properties of SBR/m-HNT nanocomposites,especially the interfacial interactions,were investigated.SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix at ...
基金the financial support of the National Natural Science Foundation of China(22071152 and 22122105)the financial support of the National Natural Science Foundation of China(22305150)+4 种基金the financial support from the National Natural Science Foundation of China(22101175 and 52333001)Natural Science Foundation of Shanghai(22dz1207603)supported by the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(SN-ZJU-SIAS-006)State Key Laboratory of Polyolefins and Catalysis and Shanghai Key Laboratory of Catalysis Technology for Polyolefins(SKL-LCTP-202301)the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22SG11)。
文摘Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental conditions.To surmount the limitations of conventional cross-linking modes,mechanical bonds stabilized by host-guest recognition are incorporated as the cross-linking points of SBR to form mechanically interlocked networks(MINs).Compared with covalently cross-linked network,the representative MIN exhibits superior mechanical performance in terms of elongation(1392%)and breaking strength(4.6 MPa),whose toughness has surged by 17 times.Dissociation of host-guest recognition and subsequent sliding motion provide an effective energy dissipation mechanism,and the release of hidden length is also beneficial to enhance toughness.Furthermore,the introduction of the rotaxane cross-links made the network more pliable and possess damping and elastic properties,which can return to initial state with one minute rest interval.We aspire that this direct introduction method can serve as a blueprint,offering valuable insights for the enhancement of mechanical properties in conventional commercial polymer materials.
基金financially supported by Natural Science Foundation of Shanxi Province(No.202303021211075)Shanxi Province Science and Technology Key Research and Development Project(No.201903D321065)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2021SX-TD011)。
文摘The antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine(4010NA)was dissolved in ethanol and impregnated into silica aerogel(SAG)via vacuum-pressure cycles,yielding composite particles(A-N)with enhanced sustained-release and reinforcing capabilities.The effect of A-N on the mechanical properties and thermal-oxidative aging resistance of styrene-butadiene rubber(SBR)vulcanizates was investigated.TGA and BET assessments indicated that the loading efficiency of 4010NA in SAG reached 14.26%within ethanol's solu bility limit.Incorporating A-N into SBR vulcanizates significantly elevated tensile strength by 17.5%and elongation at break by 41.9%over those with fumed silica and free4010NA.Furthermore,A-N notably enhanced the thermal-oxidative aging resistance of SBR.After aging for 96 h at 100℃,the tensile strength and elongation at break of SBR with A-N sustained 70.09%and 58.61%of their initial values,respectively,with the retention rate of elongation at break being 62.8%higher than that of SBR with fumed silica and free antioxidant.The study revealed that A-N composite particles significantly inhibited the crosslinking in SBR's molecular chains,reducing hardening and embrittlement during later thermal-oxidative aging stages.
文摘For the first time, this paper describes the concentration dependence of the relative dynamic viscosity coefficient of rubber suspensions and the initial viscoelastic modulus of 3D cross-linked elastomers on the maximum volume filling with solid polydisperse particles. It allows to predict the rheological and mechanical properties of the polymer compositions being developed now. In this paper, we present the first experimental study of the pole of the concurrent lines of the concentration dependence in the coordinates of the linear form. The pole validates the invariant value of the constant of the developed equation and allows the experimental determination of the maximum volume filling of polymer binders filled with separate fractions or polydisperse mixtures. The results of the study are recommended for use in developing new polymer composite materials.
