2-mercaptobenzothiazole Research Articles

Water Diffusion in Natural Rubber Vulcanizates: Effect of Ingredient Loading on Swelling and Mechanical Properties

The effect of compounding ingredients to swelling and mechanical properties of vulcanized natural rubber (NR) in deionized water at 80°C was investigated. Rubber sheets are compounded according to a fractional factorial design of experiment, where ingredients are treated as factors varied at two levels of loading. Results show that sulfur, used oil, calcium carbonate (CaCO3), reclaimed rubber, asphalt, diphenyl guanidine (DPG), mercaptobenzothiazole (MBT), and mercaptobenzothiazole disulfide (MBTS) are some of the significant ingredients of the formulation affecting the material properties of vulcanized NR. Among the compounding ingredients, sulfur and used oil are the most influential and consistent factors which affect the swelling and tensile properties of vulcanized NR during water diffusion.

The interaction of sodium mercaptobenzothiazole with gold electrode and nanorod surfaces

Attenuated total reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy have been applied to characterise and investigate the interaction of sodium mercaptobenzothiazole (MBT) with gold surfaces and gold nanorods. Gold nanorods (Au NRs) with average aspect ratio of 4.04±0.08 were synthesised and reacted with MBT. Gold(I) mercaptobenzothiazole and the dithiolate, 2,2′-dithiobisbenzothiazole ((MBT)2) were synthesised and characterised to provide a basis for compound identification. It was concluded that MBT could link two Au NRs by adsorption through the exocyclic S atom on one NR and the endocyclic S atom on the other NR, thereby leading to the formation of Au nanochains in the suspension. The MBT flotation of 100μm gold particles was also investigated utilising controlled potential techniques. The gold metal particles floated in the cell when the potential reached 0.5V. At that potential, (MBT)2 was observed on the gold particles, and their floatability was attributed to the adsorption of that dithiolate species.

Facile synthesis and characterization of thiol-functionalized graphene oxide as effective adsorbent for Hg(II)

In this work, we report the synthesized and characterization of mercaptobenzothiazole (MBT) functionalized graphene oxide (GO) as a novel adsorbent material for the adsorption of Hg(II). This adsorption process could be realized with GO and MBT acting as host-guest in the first instance followed by the subsequent complexation of Hg(II) with MBT, the soft–soft interaction between Hg(II) & sulphur enhances the effective complexation. The prepared graphene-based adsorbent was characterised by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Powder-X-ray diffraction (Powder-XRD), Transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, scanning electron microscopes (SEM) and energy-dispersive X-ray analysis (EDX). The capability of ICP-MS for Hg(II) adsorption was extensively studied under different optimal parameters, the developed method was successfully applied to mercury adsorption from water samples.

Effect of Ingredient Loading on Water Transport Properties of a Vulcanized Natural Rubber Compound

Water transport properties of a vulcanized natural rubber compound are studied as function of ingredient loading using gravimetric method at 800C. Rubber sheets are compounded according to a fractional factorial design of experiment, where ingredients are treated as factors varied at two levels of loading. Weight change during immersion in water is monitored. The maximum uptakes are determined from the sorption curves which showed two distinct slopes of which two uptake rates are estimated. Analysis of variance shows that high loadings of sulfur, asphalt, and used oil significantly increase the maximum uptake and first uptake rate while only sulfur and asphalt significantly increase the second uptake rate. On the other hand, high loadings of reclaimed rubber, calcium carbonate (CaCO3), mercaptobenzothiazole (MBT) significantly decrease the maximum amount of water uptake. Similarly, high loading of mercaptobenzothiazole disulfide (MBTS) significantly decrease the initial uptake rate while high loadings of reclaimed rubber, CaCO3, kaolin clay, and MBT decrease the final uptake rate of rubber compounds.

Effect of Ingredient Loading on Surface Migration of Additives in a Surfactant-Loaded Natural Rubber Vulcanizate

Surface migration of additives in a surfactant-loaded natural rubber vulcanizate is investigated as function of ingredient loading. Rubber sheets are compounded according to an L12 orthogonal array using Taguchi design of experiment, where ingredients are treated as factors varied at low and high loadings. Migration experiments are performed by placing the rubber sheets in a natural convection oven at 50°C for 32 days. Weight loss due to removal of migrated additives from surface of rubber sheets is monitored with time. The maximum amount and estimated rate of additive migration are determined from weight loss curves. Attenuated total reflection – Fourier transform infrared (ATR-FTIR) spectroscopy and optical microscopy are used to characterize the chemical structure and surface morphology of rubber sheets during additive migration. Mean effects and analysis of variance (ANOVA) show that high loadings of used oil, paraffin wax, stearic acid, glycerol monostearate (GMS), and cocamide diethanolamide (Coca DEA) increase the amount of maximum migration and migration rate of additives. On the other hand, high loadings of mercaptobenzothiazole (MBT), diphenylguanidine (DPG), mercaptobenzothiazole disulfide (MBTS), sulfur, and zinc oxide (ZnO) decrease the maximum amount of additive migration and migration rate. Used oil has the highest effect on these responses, while sulfur and the accelerators have the least effect. By comparing the of ATR-FTIR spectra of cleaned and migrated rubber surfaces, almost all soluble additives are identified to have migrated to the rubber surface.

Self healing coatings containing dual active agent loaded urea formaldehyde (UF) microcapsules

Abstract Urea formaldehyde (UF) microcapsules loaded with linseed oil and mercaptobenzothiazole (MBT) as core materials have been synthesized by in situ emulsion polymerization. The capsules were characterized by FTIR. Surface morphology of microcapsules was analyzed using scanning electron microscope. The thermal stability of the microcapsules is in the temperature range around 600 °C as confirmed by TG analysis. The open circuit potential measurements have shown that the coatings with microcapsules maintain the potential in the noble range (≈−0.390 V vs. SCE) while the coating without microcapsules exhibit potentials in the active range. EIS studies at the artificial defect area have shown that the coating containing microcapsules is able to protect steel in neutral media since the impedance values remained at 10 7 Ω cm 2 even after 15 days exposure where as the coatings without microcapsules have lost their protection ability. The self healing ability of the coating containing microcapsules was studied by SVET.

Synthesis, Characterization and Antitumour Activity of Diorganotin (IV) Complexes Containing Silicon of 2-Mercaptobenzothiazole

合成了6个含硅二烃基锡（IV）的2-巯基苯并噻唑配合物R^1R^2SnL2（R^1=Me3SiCH2,R^2=Me3SiCH2或Ph,Cy;R^1=EtMe2SiCH2,R^2=EtMe2SiCH2或Ph,Cy.LH=2-硫基苯并噻唑）,并通过IR、^1H NMR、^13C NMR、元素分析和X射线单晶衍射对目标化合物进行结构表征.结果表明,配体L以硫醇互变异构体形式与锡原子配位,形成了以锡为中心的六配位扭曲八面体结构;生物活性试验的初步结果显示,含硅二烃基锡（IV）-2-巯基苯并噻唑对肺腺癌细胞（A549）具有较强的体外抗癌活性.

An environmentally benign and efficient synthesis of 2-thio-substituted benzothiazoles

An environmentally benign, simple and highly efficient method for the synthesis of 2-thio-substituted benzothiazole derivatives has been achieved in good to excellent yields by reacting a series of aryl halides with 2-mercapto benzothiazole, using recyclable CuFe 2 O 4 nanoparticles under ligand free conditions in PEG-400 as solvent. In the present protocol, the copper ferrite nanoparticles can be recovered and reused up to four cycles without significant loss of activity.

Modification of gold electrode by self-assembled 2-mercapto benzothiazole for the determination of Hg2+

An electrochemical method was developed for the determination of mercury using polycrystalline gold electrode modified by self-assembled monolayers (SAMs) of 2-mercaptobenzothiazole (MBTH). Morphological and electrochemical characterisation of the self-assembled structure of MBTH was performed using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) measurements. The monolayer of MBTH has shown high affinity for Hg2+. The limit of detection for the determination of Hg2+ using the MBTH SAMs modified gold electrode was obtained as 0.421 μg L−1. The pre-concentration of Hg2+ at open circuit potential is beneficial for the onsite monitoring of mercury concentration in water samples.

Synergism of novel thiuram disulfide and dibenzothiazyl disulfide in the vulcanization of natural rubber: curing, mechanical and aging resistance properties

Various combinations of synthesized thiuram disulfides (TD), namely Bis (N-phenyl piperazine) thiuram disulfide (PPTD) and Bis (N-ethyl piperazine) thiuram disulfide (EPTD) with mercapto benzothiazole disulfide (MBTS) are studied in natural rubber (NR) vulcanization. At the same time, we also revised the TD-MBTS binary accelerator on the carbon black-filled NR system. An evaluation is prepared between the synthesized safe thiuram disulfides with the unsafe tetra methyl thiuram disulfide (TMTD) in the light of mechanical and aging resistance behavior to introduce non-carcinogenic rubber additives to vulcanization of rubber. Synthesized safe amine-based thiuram disulfides in combination with MBTS display strong synergism in the gum vulcanization. Higher concentration of thiuram disulfide in presence of MBTS (6:3 mM ratio) shows better results with respect to cure and physical properties. In the specific concentration of 9 mM per hundred gram of rubber (6:3 mM ratio of TD to MBTS), however, PPTD-MBTS accelerated filled vulcanizates show utmost aging resistance behavior, but EPTD-MBTS accelerated filled stock spectacles show superior aging as well as mechanical properties as compared to that of TMTD-MBTS accelerated system.

Concomitant Patch Test Reactions to Mercapto Mix and Mercaptobenzothiazole

Mercaptobenzothiazole (MBT) and mercapto compounds are primarily used in rubber products. This study aimed to examine concomitant-positive rates of MBT (1% pet) and the 4-part mercapto mix (MM) (1% pet). This is a retrospective cross-sectional data from the North American Contact Dermatitis Group. A total of 30,880 patients were patch tested to MM and MBT. There were 333 positive reactions to MM and 427 positive reactions to MBT. Ninety-eight patients were positive to MM alone, 192 to MBT alone, and 235 reacted to both. Forty-five percent (192/427) of MBT reactions would have been missed by only testing to MM, and 29% (98/333) of MM reactions would have been missed by testing to MBT alone. Most of these "missed" reactions, however, were doubtful (+/-) or mild (+) (MBT, 65%; MM, 78%), whereas most reactions in patients who reacted to both were moderate (++) and/or strong (+++) (52.3%). Gloves were the most common source. Mercaptobenzothiazole is the preferential screening allergen for mercapto compounds because of the following: (1) greater proportion of missed reactions with MM; (2) greater proportion of doubtful/mild reactions in the missed group for MM; and (3) in the group positive to both, the low rate (2%) of moderate/strong reactions to MM and doubtful/mild reactions to MBT as compared with the converse (21%). Mercapto mix may be useful in an auxiliary rubber series.

BIA, DPA, MBTA and DMA as Vapour Phase Corrosion Inhibitors for Mild Steel under Different Atmospheric Conditions

Mild steel is widely used as main raw material in fabrication of equipment, chief material of construction and as weapons. During its storage and transportation conditions, it comes in contact with aggressive environment which leads to decrease in mechanical strength and loss in useful properties. Four different vapor phase corrosion inhibitors (VPCIs) i.e. Benzaimidazole (BIA), Diphenyl amine (DPA), 2-mercapto benzothiazole (MBTA) and N,N-dimethyl aniline (DMA) were tested under different atmospheric conditions at 40 °C by Weight Loss, Eschke test, Salt Spray, SO2 test and SEM techniques. All the four VPCIs show good corrosion inhibition efficiency i.e. 65-96 %. The results obtained from all the four corrosion experiments were supported by SEM images.

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

ABSTRACTBinary 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.

BIA, DPA, MBTA and DMA as Vapour Phase Corrosion Inhibitors for Mild Steel under Different Atmospheric Conditions

Mild steel is widely used as main raw material in fabrication of equipment, chief material of construction and as weapons. During its storage and transportation conditions, it comes in contact with aggressive environment which leads to decrease in mechanical strength and loss in useful properties. Four different vapor phase corrosion inhibitors (VPCIs) i.e. Benzaimidazole (BIA), Diphenyl amine (DPA), 2-mercapto benzothiazole (MBTA) and N,N-dimethyl aniline (DMA) were tested under different atmospheric conditions at 40 °C by Weight Loss, Eschke test, Salt Spray, SO2 test and SEM techniques. All the four VPCIs show good corrosion inhibition efficiency i.e. 65-96 %. The results obtained from all the four corrosion experiments were supported by SEM images.

Adsorptive Demercuration by Virtue of an Appealing Interaction Involving Biopolymer Cellulose and Mercaptobenzothiazole

In this work, we present an interesting method for the adsorption of Hg(II) involving its interaction with cellulose and mercaptobenzothiazole (MBT). This affinity could be realized with cellulose ...

Influence of gold mineralogy on its flotation recovery in a porphyry copper–gold ore

The present study investigates the implications of gold mineralogy on its flotation recovery, in a typical porphyry copper–gold ore (1.7g/t Au feed grade). Also, flotation strategies to optimise gold recovery and grade without compromising copper recovery and grade were examined. The approach used in this study involves a combination of different mineralogical techniques such as quantitative X-ray diffraction (QXRD) and scanning electron microscopy (QEMSCAN). Based on the mineralogical information obtained, different collector regimes involving sodium iso-butyl xanthate (SIBX), N-butoxycarbonyl-n butyl thionocarbamate (XD5002), mercaptobenzothiazole (MBT) and dithiophosphate (DTP) at different grind sizes (p80, i.e. a nominal product size of 80wt% passing (a) 70µm and (b) 38µm screen) were tested to examine the flotation behaviour of gold in relation to copper recovery. Chalcopyrite and covellite are the principal copper mineral phases in the ore, with pyrite as the main sulphide gangue mineral. Quartz, Fe oxide and carbonates were identified as the main non-sulfide gangue minerals. The identified gold particles occurred as either liberated particles (∼10–22µm) or fine inclusions (∼1–3µm) in pyrite, biotite and sphalerite. Two-stage flotation (copper and pyrite rougher stages) at a p80 of 70µm indicated that high gold (95.2%) and copper (97.4%) recovery can be achieved, but the levels of pyrite in the concentrate are also very high (49.1%). At finer grind (p80=38µm) and without pyrite flotation stage, gold recovery decreased from 95.2% to 73%, but at an improved grade (5.3g/t) compared to 3.5g/t in the baseline. This approach improved gold grade significantly due to a drastic reduction in pyrite recovery. The flotation study indicates that the collector regime, SIBX/XD5002 (at 38µm feed size) gives the maximum gold recovery and grade while rejecting significant pyrite without compromising copper recovery and grade. Further studies are warranted to identify means of recovering Au from the copper flotation tail.

Prevalence of Occupational Contact Dermatitis to Mercaptobenzothiazole in a Population of Seamen and Prognosis after 3-Year Evaluation

Background: The prevalence of contact dermatitis to mercaptobenzothiazole (MBT) in the maritime work place and its prognosis have been poorly studied. Objectives: Determining the clinical presentation as well as the annual incidence rate of on set of skin allergies to MBT in the maritime workplace, and attempting to gauge the social and professional impact of this condition on affected seafarers. Materials and methods: Analysis of the medical records of the seafarers who reported a skin allergy to MBT in 2008, and calculation of the prevalence of this condition amongst the 35 563 professional seafarers exposed to MBT in France because they wear work clothes made of synthetic rubber in their occupational activities (catch handling, merchant shipping or shellfish farming). Results: We found only three cases in professional fishermen. In all cases, the dermatitis persisted despite the arrest of exposure to MBT, and made very difficult, the continuation of their professional life of these patients in the fishing sector. Conclusion: The prevalence of contact dermatitis to MBT in the maritime sector is 1/10 000. The 3-year prognosis is poor since the seafarers affected by this disease reported the persistence of lesions and the health-imposed obligation to cease working in the fishing industry.

Selective Flotation of Chalcopyrite and Marmatite by MBT and Electrochemical Analysis

Various collectors were compared in the selective flotation of copper–zinc ore by using isopropyl ethylthionocarbamate (Z-200), buthl xanthate, ammonium dibutyl dithiophosphate, and mercapto benzothiazole (MBT). The latter showed effective selectivity in the flotation of chalcopyrite and marmatite and was selected for a detailed study by using cyclic voltammetry and Tafel. The results of microflotation pointed out that the flotation of marmatite was significantly affected by CuSO4 activation. At weakly alkaline pH, marmatite activated by Cu2+ is dependent on Cu2+ concentration shown in electrochemical tests, and the activation products were Cu2S and CuS. The increasing addition of Cu2+ may remove the hydroxides and S0, resulting in considerable activation. The corrosion of marmatite is accelerated with the addition of CuSO4. Mechanisms are suggested for the selectivity of chalcopyrite/marmatite by MBT: the hydrophilic hydroxides (Zn(OH)2 and Fe(OH)3) are formed on the marmatite surface, which renders the marmatite surface hydrophilic and hampers the reaction between MBT and marmatite-activated products, while the hydrophobic compounds (MBT)2 and Cu(MBT)2 formed on the chalcopyrite surface improve the flotability of chalcopyrite.

Thiazole계 가황촉진제가 실란/실리카 충전 천연고무 컴파운드의 가황 거동 및 기계적 물성에 미치는 영향

본 연구에서는 thiazole 계 촉진제인 2-mercapto benzothiazole(MBT)의 첨가량을 변화시켜(0, 1, 2, 3, 4 phr) 실란/실리카로 충전된 천연고무 컴파운드에 첨가하여 가황속도, 물성, 고무-충전제간 상호작용계수(<TEX>${\alpha}_F$</TEX>), 가교밀도 및 탄젠트 델타(<TEX>$tan{\delta}$</TEX>)에 미치는 영향을 비교 평가하였다. 촉진제의 첨가량이 증가할수록 <TEX>$t_{s2}$</TEX>, <TEX>$t_{90}$</TEX> 가황시간은 빨라졌고 가교 밀도 및 300% 모듈러스는 증가하였다. 인장강도와 신장률 또한 증가하였으나 3 phr에서는 더 이상의 증가가 없었다. 그리고 상온에서의 <TEX>$tan{\delta}$</TEX> 값은 <TEX>$70^{\circ}C$</TEX>에서보다 높은 값을 나타내었다. 촉진제의 함량변화는 천연고무-실란/실리카간 상호관계(<TEX>${\alpha}_F$</TEX>)에 큰 영향을 미치지 않는 것으로 관찰되었다. 가황속도에 미치는 메카니즘을 고찰하였다. A thiazole type accelerator MBT (2-mercapto benzothiazole) was added into silica filled natural rubber (NR) compound with various concentrations (0, 1, 2, 3, 4 phr). The effects of MBT on the cure rate, mechanical property, degree of rubber-filler interaction (<TEX>${\alpha}_F$</TEX>), crosslinking density, and viscoelastic property (<TEX>$tan{\delta}$</TEX>) were investigated. As accelerator concentration increased, the <TEX>$t_{s2}$</TEX> and <TEX>$t_{90}$</TEX> decreased and the crosslinking density and modulus at 300% elongation increased. The tensile strength and elongation increased up to 3 phr and no further increased at 4 phr. The <TEX>$tan{\delta}$</TEX> value measured at room temperature was higher than that of the <TEX>$70^{\circ}C$</TEX>. The <TEX>${\alpha}_F$</TEX> value was not affected by the addition of MBT. The mechanisms for the vulcanization rate were reviewed.

Synthesis of novel 2-mercapto benzothiazole and 1,2,3-triazole based bis-heterocycles: Their anti-inflammatory and anti-nociceptive activities

A focused library of novel bis-heterocycles encompassing 2-mercapto benzothiazole and 1,2,3-triazoles were synthesized using click chemistry approach. The synthesized compounds have been tested for their anti-inflammatory activity by using biochemical cyclooxygenase (COX) activity assays and carrageenan-induced hind paw edema. Among the tested compounds, compound 4d demonstrated a potent selective COX-2 inhibition with COX-2/COX-1 ratio of 0.44. Results from carrageenan-induced hind paw edema showed that compounds 4a, 4d, 4e and 4f posses significant anti-inflammatory activity as compared to the standard drug Ibuprofen. The compounds showing significant activity were further subjected to anti-nociceptive activity by writhing test. These four compounds have shown comparable activity with the standard Ibuprofen. Further ulcerogenic studies shows that none of these compounds causing gastric ulceration.