热脱附气相色谱-质谱联用鉴定硫化胶中促进剂种类

研究热脱附气相色谱-质谱联用进行硫化胶中常用促进剂的定性分析。结果表明:当特征反应产物仅有苯并噻唑基团时,可判定为促进剂MBT或MBTS;当除苯并噻唑基团外,还有对应促进剂反应产物中的其他基团时,可以判定次磺酰胺类促进剂的具体种类。该方法可直接分析硫化胶固体样品,有效避免促进剂特征产物的丢失,结果准确可靠。     

促进剂种类对ZnO硫化BIIR的影响

通过改变促进剂种类,研究了ZnO-促进剂硫化体系对溴化丁基橡胶(BIIR)硫化特性、硫化反应动力学参数及硫化胶物理机械性能的影响。研究表明,促进剂二硫化二苯并噻唑(MBTS)、N-环己基-2-苯并噻唑次磺酰胺(CBS)抑制了ZnO对BIIR的硫化,使硫化胶的交联密度降低,硫化胶的物理机械性能下降;促进剂二硫化四甲基秋兰姆(TMTD)和二甲基二硫代氨基甲酸锌(ZDMC)则促进了ZnO对BIIR的硫化,提高了硫化胶的物理机械性能;MBTS、TMTD、ZDMC均降低了ZnO硫化BIIR的反应活化能。     

气相色谱-质谱联用法鉴定硫化胶中促进剂

采用气相色谱-质谱联用法鉴定分析硫化胶中促进剂种类。结果表明,部分促进剂在橡胶硫化过程中发生了分解及重组反应,但通过其单体及反应产物的特征离子基本可以定性硫化胶所使用的促进剂种类,其中噻唑类和次磺酰胺类促进剂由于含有苯并噻唑碎片,当有次磺酰胺类促进剂存在时,不能确定该配方中是否含有促进剂M。     

二硫代氨基甲酸锌和噻唑类促进剂并用对天然橡胶的硫化作用

在噻唑类促进剂存在情况下,研究了天然橡胶硫化过程中由安全胺衍生的几种二硫代氨基甲酸锌(ZDCs)生成安全的二硫代氨基甲酸盐。比较了常规的不安全的二甲基二硫代氨基甲酸锌(ZDMC)与结合了噻唑类促进剂的安全的ZDC的力学性能。研究表明,二硫化秋兰姆和2-巯基苯并噻唑(MBT)总是形成于ZDC与二硫化二苯并噻唑(MBTS)或ZDC与N-环己-2-苯并噻唑次磺酰胺(CBS)的反应过程。结果证明,从MTBS或CBS生成的MBT与ZDC反应生成二硫化四甲基秋兰姆。根据硫化和物理数据讨论了此协同活性,并采用高效液相色谱分析结果,对反应机理进行了解释。在研究的所有双组份系统中都观察到了协同活性。当二硫代氨基甲酸锌(N-苄基哌唑)促进系统中的比例为3:6mM时,获得最高的拉伸强度。在拉伸强度和模量值方面,结合噻唑基的安全ZDCs促进剂可以成功替代不安全的ZDMC。     

GC-MS法鉴定硫化橡胶促进剂的研究

本实验采用气相色谱-质谱联用仪来分析硫化橡胶的丙酮抽提液,从而确定橡胶制品中所用的促进剂类型。实验结果表明,虽然部分促进剂在橡胶硫化过程中发生了分解及重组反应,但是通过其单体及反应产物的特征离子基本可以定性硫化胶中所使用的促进剂类型,其中噻唑类和次磺酰胺类促进剂由于都含有苯并噻唑碎片,故当有次黄酰胺类的促进剂存在时,不能确定该配方中是否含有促进剂M。     

万吨级促进剂微化工技术国际领先

<正>2019年10月23日,"万吨级橡胶促进剂MBT,MBTS微化工连续流生产技术开发"项目在北京通过了中国石油和化学工业联合会组织的科技成果鉴定。应用该技术建成了国际上首套2. 2万t·a~(-1)2-巯基苯并噻唑(促进剂MBT)和1. 2万t·a~(-1)2,2′-二硫代二苯并噻唑(促进剂MBTS)微化工连续流生产装置,引领了橡胶助剂产业转型升级和可持续发展。该成果由蔚林新材料科技股份有限公司与清     

橡胶促进剂微化工技术通过鉴定

2019年10月23日,中国石油和化学工业联合会在北京组织有关专家对蔚林新材料科技股份有限公司与清华大学共同完成的"万吨级橡胶促进剂MBT、MBTS微化工连续流生产技术开发"项目进行了科技成果鉴定。与会专家认为,该项目针对橡胶促进剂2-巯基苯并噻唑(MBT)和2,2'-二硫代二苯并噻唑(MBTS)的关键生产环节,基于微混合、微萃取和微反应原理创制了微化工连续流工艺和生产装置,取得3方面技术创新:一是建成了国际首套基于微混合强化的连续流生产MBT万吨级工业化装置,提出了多段精确控温反应的新工艺,产能达22kt/a,反应时间从8h降至3.5h,与传统间歇反应相比,设备体积减小67%,建设成本减少50%以上,MBT综合收率从90%提高至95%,能耗降低60%;二是开发了国际首套MBT微分散萃取连续精制装置与工艺,通过甲苯萃取分离MBT碱溶物中的副产物苯并噻唑,解决了体系的乳化问题,苯并噻唑萃取率大于99%,设备体积仅相当于传统设备的10%;三是开发了国际首套万吨级MBTS微反应连续合成装置与技术,提出了过氧化氢混酸多段氧化工艺,建成了12kt/a工业示范装置,MBTS收率大于98%,与原工艺相比,装置体积缩小至1/25,废水排放量减少67%,废水化学需氧量减少60%。     

防焦剂CTP的作用原理

防焦剂CTP在含硫黄的硫化体系中作用明显，如果不加硫黄，防焦剂CTP作用微弱。防焦剂CTP与硫黄并用时，次磺酰胺类促进剂之所以具有延迟效应，是由于在发生交联前，次磺酰胺必须转变为多硫代苯并噻唑中间体。在发生硫化和硫黄含量显若减少之前，次磺酰胺类促进剂已经大量被消耗。至此，中间体2-巯基苯并噻唑（MBT）被作为次磺酰胺和硫黄反应的自动催化剂。防焦剂CTP在这种连续的自动催化反应过程中移去了MBT，因而延迟了多硫代苯并噻唑的生成和在交联之前发生的化学反应。     

万吨级促进剂微化工技术国际领先

<正>10月23日,"万吨级橡胶促进剂MBT、MBTS微化工连续流生产技术开发"项目在北京通过了中国石油和化学工业联合会组织的科技成果鉴定。应用该技术建成了国际上首套22 kt/a 2-巯基苯并噻唑(MBT)和12 kt/a 2,2’-二硫代二苯并噻唑(MBTS)微化工连续流生产装置,引领了橡胶助剂产业转型升级和可持续发展。     

硫化天然橡胶的结构特性研究

本研究着重于评价各种硫黄硫化的网络结构,以及它们对由四种含N-甲基哌嗪的安全的二元促进剂并用体系得到的硫化橡胶的强度的响,这四种二元体系:(i)2-巯基苯并噻唑(MBT)和秋兰姆,(ii)N-环已基-2-苯并噻唑次磺酰胺(CBS)和秋兰姆,(iii)2-巯基苯并噻唑基二硫化物(MBST)和硫代氨基甲酰次磺酰胺,(iv)2-巯基苯并噻唑基二硫化物(MBTS)与二硫代二胺。本研究提示了对于橡胶制品的生产而言,MBTS-MPTS体系是一种安全的促进剂并用体系。在有MBTS的情况下,二硫代二胺对纯胶硫化胶的强度和交联数显示了最高的活性,但是对于加炭黑的胶料则情形相反。本研究中对此提出了可能的反应机理。从有关各种硫黄硫化交联键的分布数据来看,二硫交联键对提高硫化橡胶的拉伸强度有显著的作用。     

The reactions of 2‐(4‐morpholinothio)‐ and 2‐(4‐morpholinodithio) benzothiazole in the absence of polyisoprene

2‐(4‐morpholinothio)benzothiazole (MOR) and 2‐(4‐morpholinodithio)benzothiazole (MDB) were heated with sulfur and ZnO in a DSC. The products formed at various temperatures were identified and analyzed by HPLC. At temperatures below 200°C, decomposition of the accelerator in the absence of other curatives was slow, degradation products being mainly 2‐bisbenzothiazole‐2,2′‐disulfide (MBTS) and 2‐mercaptobenzothiazole (MBT). A rapid exothermic decomposition above 200°C resulted in the formation of MBT (or its amine salt) and 2‐(4‐morpholino)benzothiazole (MB). MOR and MDB reacted with sulfur to form higher polysulfides. MDB was shown to react more readily with sulfur than MOR and the delayed action of MOR in rubber can therefore not be ascribed to a stable polysulfide as suggested by other authors. Neither MOR nor MDB was found to react with ZnO. A limited reaction between MBT and ZnO was observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1235–1240, 1999     

Sulfur vulcanization of polyisoprene accelerated by benzothiazole derivatives. III. The reaction of 2-bisbenzothiazole-2,2′-disulfide with sulfur and ZnO in polyisoprene

The sulfur vulcanization of polyisoprene accelerated by 2-bisbenzothiazole-2,2′-disulfide (MBTS) was investigated. Rubber compounds were heated in a DSC and removed at various temperatures along the DSC thermal curve. The rubber vulcanizate was analyzed for crosslink density and for residual reactants and extractable reaction products. MBTS reacts readily with sulfur, and the polysulfidic accelerator complexes react with the rubber chain to form pendent groups. Crosslinking results from hydrogen abstraction, by the benzothiazole pendent group, from a neighboring chain. 2-Mercaptobenzothiazole, a product of crosslinking, also acts as an accelerator in the later stages of the reaction. MBTS has been shown not to react with ZnO and the higher crosslink densities obtained when ZnO is present are attributed to ZnO aiding the abstraction of the benzothiazole pendent group to give zinc mercaptobenzothiazole. A mechanism for the MBTS acceleration of sulfur vulcanization is proposed. © 1996 John Wiley & Sons, Inc.     

Sulfur vulcanization of polyisoprene accelerated by benzothiazole derivatives. IV. The reaction of polyisoprene with N-cyclohexylbenzothiazole sulfenamide,sulfur, and zinc oxide

Polyisoprene was vulcanized with N-cyclohexylbenzothiazole sulfenamide (CBS), sulfur, and zinc oxide by heating in a Differential Scanning Calorimeter (DSC) at a programmed rate to given temperatures. The reaction was quenched and the product analyzed. Soluble curatives and reaction intermediates were analyzed by high-performance liquid chomatography (HPLC) and the crosslink density of the network determined by swelling. The delayed action of the CBS accelerator is explained in terms of an exchange reaction between benzothiazole terminated polysulfidic pendent groups on the polymer chain and CBS to yield unreactive amine terminated pendent groups and 2-bisbenzothiazole-2,2′-disulfide (MBTS). MBTS reacts with sulfur to form 2-bisbenzothiazole-2,2′-polysulfides (MBTPs), which also form pendent groups. Crosslinking does not commence until all of the CBS has been consumed and pendent groups are no longer deactivated. 2-Mercaptobenzothiazole (MBT) is released only on crosslinking. When MBT is present in the formulation at the outset of the reaction it traps cyclohexylamine released when CBS adds to the chain as a pendent group. The MBT-amine salt participates in a reaction that regenerates MBTS, which is, thus, not consumed in the vulcanization process. ZnO does not react with CBS, and its role in increasing the crosslink density is attributed to its promoting crosslinking reactions between pendent groups and neighboring chains rather than intramolecular reactions, which lead to cyclization. © 1996 John Wiley & Sons, Inc.     

The thermal decomposition of sulfenamide accelerators

The thermal decomposition of three sulfenamide accelerators N-cyclohexylbenzothiazole sulfenamide (CBS), 2-(4-morpholinothio) benzothiazole (MOR) and 2-t-butylaminobenzothiazole sulfenamide (TBBS) were investigated by differential scanning calorimetry. The sulfenamides decompose rapidly at 210–220°C, yielding a number of products, including reactive polysulfidic complexes. Thus, CBS gives N-cyclohexylamino-2-benzothiazole polysulfides (CBP), 2-bisbenzothiazole-2,2′-disulfide (MBTS), 2-bisbenzothiazole-2,2′-polysulfides (MBTP), 2-bisbenzothiazole-2,2′-monosulfide (MBTM), 2-mercaptobenzothiazole (MBT), and 2-N-cyclohexylaminobenzothiazole (CB). The polysulfides are unstable, and on prolonged heating, only MBT and CB remain. The amine fragment of the accelerator is present as the amine salt of MBT. At lower temperatures, the sulfenamides are relatively stable. MOR forms an analogous product spectrum. The decomposition of TBBS is endothermic, in contrast to the exothermic reaction observed with CBS and MOR, and the concentrations of the various polysulfides do not decrease on prolonged heating. Reaction mechanisms are proposed to account for the formation of the products. © 1994 John Wiley & Sons, Inc.     

Studies on cure synergism. I. Effect of safe zinc dithiocarbamates on NR vulcanization accelerated by thiazole-based accelerators

Investigations have been carried out on the effect of several zinc dithiocarbamates in the presence of thiazole-based accelerators in the vulcanization of natural rubber (NR), keeping in mind the possibility of introducing safe dithiocarbamates derived from safe amines. Mutual activity is observed in all the binary systems studied, the highest being observed in the zinc dibenzyldithiocarbamate-dibenzothiazyldisulfide (ZBEC–MBTS)-accelerated system. The effect of zinc diisopropyl dithiophosphate, reportedly a safe rubber additive, which is recognized as an age-resistant agent for NR, on cure has also been studied. The study reveals that thiuram disulfide and MBT are always formed from the reaction either between zinc dithiocarbamate (ZDC) and MBTS or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that 2-mercaptobenzothiazole (MBT) generated from MBTS or CBS reacts with ZDC and produces tetramethyl thinram disulfide (TMTD). The observed mutual activity has been discussed based on the cure and physical data and explained through the results based on HPLC and a reaction mechanism. © 1994 John Wiley & Sons, Inc.     

Safe amine based zinc dithiocarbamates for the vulcanization of carbon black reinforced natural rubber

Binary combination of three safe amine based synthesized zinc dithiocarbamates (ZDC), namely zinc (N‐benzyl piperazino) dithiocarbamate (ZBPDC), zinc (N‐ethyl piperazino) dithiocarbamate (ZEPDC), and zinc (N‐phenyl piperazino) dithiocarbamate (ZPPDC) with mercapto benzothiazole disulfide (MBTS) as an effective accelerator system for the vulcanization of carbon black (N330, N550, and N774) filled natural rubber (NR) composites are studied. A comparison between the safe amine based zinc dithiocarbamates with the unsafe zinc dimethyl dithiocarbamate (ZDMC) in the light of mechanical and aging resistance behavior, introduces the non carcinogenic rubber additives in the filled vulcanization of rubber. Both accelerator and filler have the major importance for improving the mechanical as well as aging resistance behavior of the resultant vulcanizate. Variation in the filler and also filler to oil ratio are done to optimize the mechanical properties. SEM studies of different types of filler with different amounts show that N330 at 30 phr loading composites forms more homogeneity and less aggregated structures. Natural rubber systems with N330 carbon black show the best results with respect to tensile strength, but after the aging N774 carbon black filled system indicates better retention in the tensile strength. ZPPDC‐MBTS accelerated vulcanizate shows the better age resistance behavior than ZDMC‐MBTS accelerated vulcanizate. From both the points of age resistance and mechanical properties, ZBPDC‐MBTS accelerator system is the suitable substitute for ZDMC‐MBTS accelerated system in the filled vulcanization of natural rubber composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39988.     

Studies on the effect of thiuram disulfide on NR vulcanization accelerated by thiazole-based accelerator systems

Thiuram disulfides form synergistic combinations with thiazole and thiazole-based accelerators, namely, N-cyclohexy-2-benzothiazole sulfenamide (CBS), 2-mercaptobenzothiazole(MBT), and 2-mercaptobenzothiazyl disulfide (MBTS). Unfortunately, widely used thiuram disulfides (TD) generate carcinogenic N-nitrosoamine. It is reported that the nitrosamines from N-methylpiperazine and dibenzylamine are free from this menace. So, some investigations were carried out with the binary combinations of each of bis(N-methylpiperazino)thiuram disulfide (MPTD), tetrabenzylthiuram disulnde (TBzTD), and tetramethyl-thiuram disulfide (TMTD) separately with CBS, MBT, and MBTS. It was observed that all the TD are activated by the CBS, MBT, or MBTS in the combinations studied. The intensity of activation is manifested in the enhancement of torque, modulus, tensile strength, cure rate, hardness, and decrease of elongation at break values and is very much dependent upon the ratio of the accelerators used. Considering the torque, modulus, tensile strength, and the elongation at break values, it apears that MPTD and TBzTD are capable of competing with the hitherto unbeaten TMTD as suitable accelerators for the vulcanization of rubber. Some investigations in respect to heat- and age-resistance behavior have also been carried out and the observed differences in the activities of various binary combinations have been explained through a mechanism. The results obtained with filled vulcanizates indicate that the binary systems comprising TD and MBTS provide fruitful results of which the TBzTD–MBTS combination seems to give the best cure and physical data for practical vulcanizates. © 1996 John Wiley & Sons, Inc.     

The interaction of sulfenamide accelerators with sulfur,ZNO, and stearic acid in the absence of rubber

The interaction of sulfur, ZnO, stearic acid, and the three sulfenamide accelerators N-cyclohexylbenzothiazole sulfenamide (CBS), 2-(4-morpholinothio) benzothiazole (MOR), and 2-t-butylaminobenzothiazole sulfenamide (TBBS) were investigated by differential scanning calorimetry in the absence of rubber. In the presence of sulfur, the same product spectrum is formed as in its absence, but at lower temperatures. Thus, CBS gives N-cyclohexylamino-2-benzothiazole polysulfides (CBP), 2-bisbenzothiazole-2,2′-disulfide (MBTS), 2-bisbenzothiazole-2,2′-polysulfides (MBTP), and 2-bisbenzothiazole-2,2′-monosulfide (MBTP), 2-mercaptobenzothiazole (MBT), and 2-N-cyclohexylaminobenzothiazole (CB). In the presence of sulfur, the amount of polysulfides formed initially is higher but the polysulfides are unstable, and on prolonged heating, only MBT and CB remain. MOR and TBBS form analogous product spectra. The sulfenamides do not react with ZnO or zinc stearate. The MBT–amine complex prevents MBT, formed on decomposition, from reacting to give zinc mercaptobenzothiazole (ZHBT). Reaction mechanisms are proposed to account for the formation of the products. © 1994 John Wiley & Sons, Inc.     

Bis(N‐benzyl piperazino) thiuram disulfide and dibenzothiazyl disulfide as synergistic safe accelerators in the vulcanization of natural rubber

Some investigation regarding the effect of binary system of accelerators comprising one safe thiuram disulfide, namely bis(N‐benzyl piperazino) thiuram disulfide (BPTD) and dibenzothiazyl disulfide (MBTS), on the vulcanization of NR is carried out. The results are compared with those obtained with conventional tetra methyl thiuram disulfide (TMTD) presently considered as unsafe. The vulcanizates obtained from safe synergistic pair of accelerators (BPTD‐MBTS) possess comparable mechanical properties [modulus, tensile strength, and elongation at break (%)] and exhibits some improvement in heat resistant behavior when compared with those obtained with TMTD‐MBTS system. In the light of mechanical properties, safe BPTD‐MBTS system introduces the safe noncarcinogenic rubber accelerator in the vulcanization of rubber. Same type of synergistic activity may be due to comparable activation energy for both the TDs with the combination of MBTS. Although rate constant values are low for BPTD‐MBTS (6 : 3) compared to TMTD‐MBTS (6 : 3) in the high temperature vulcanization, the crosslinking efficiency of former is very large compared to later. This may be responsible for improvement in heat resistance behavior of the novel accelerator in the combination with MBTS. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Vulcanization of Nitrile Rubber. Part I. Effect of Some Accelerators on the Physicomechanical Properties of Vulcanized Nitrile Rubber for Resistance to Fuel and General Use

Compounding mixtures were prepared based on acrylonitrile-butadiene rubber (Krynac 803) to which increasing parts per hundred rubber (pphr) of the following accelerates were added: tetramethyl thiuram disulfur (TMTD in series A₁), tetramethyl thiuram monosulfur (TMTM in series A₂), 2-mercaptobenzothiazole (MBT in series A₃), and 2,2′-dithiobisbenzothiazole (MBTS in series A₄). Effects of the quantity and type of accelerator on the vulcanization characteristics were studied. Physicomechanical investigations and swelling resistance were determined for samples immersed in benzene:benzol mixture at normal temperature. It was found that according to the type and quantity of accelerator, the optimum cure time decreased with increasing the quantity of accelerator. Relatively higher values of scorch time (8 min, at 1.0–3.0 pphr), which seems to ensure safe processing during production was obtained for TMTM (series A₂). TMTD (in quantity of 2.0 pphr) led to the highest value of rate of cure (14.0 min^?1). The best values of tensile strength (210 kg/cm², and 208 kg/cm²) were reached in TMTD (series A₁) and TMTM (series A₂), whereas MBT (series A₃) and MBTS (series A₄) resulted in tensile strength values of 140 and 155 kg/cm², respectively. The highest value of modulus (86 kg/cm²) was obtained in TMTD (series A₁ at 2.0 pphr). Whereas TMTD (series A₁) and TMTM (series A₂) led to relatively lower values of elongation at break (180% and 190%), it was found that MBT (series A₃) and MBTS (series A₄) led to higher values (280% and 260%). Small effects on the elasticity were observed when changing the type and quantity of accelerator. Relatively higher values of hardness were reached for series A₁ and A₂ as compared with series A₃ and A₄. The lowest values of percent volume increase after immersion in benzene:benzol mixture (8.3%) was obtained for A₁ (at 1.5 pphr of TMTD), as compared with the other three accelerators.