INFLUENCE OF ANYLES D, L- CAMPHORA ON THERMAL OXIDATING STABILITY OF BUTADIENE RUBBER BASED ELASTOMER

The influence of aniles DL-camphor as N-[(1RS)-camphane-2-ylidene]-2-methylaniline, N-[(1RS)-camphane-2-ylidene]-2-ethylaniline and N-[(1RS)-camphane-2-ylidene]aniline on vulcanization and resistance of butadiene nitrile rubber based elastomers to thermal oxidative aging was studied for the first time. The prospects of using aniles DL-camphor as anti-aging agents have been established. The best effect is achieved when using N-[(1RS)-camphane-2-ylidene]-2-methylaniline in combination with an effective vulcanisation system including sulfur donors tetramethylthiuram disulfide, 4,4'-dithiodimorpholine, and N-cyclohexylbenzothiazole-2-sulphenamide.

Enhancing the Activity of Silver Nanowire Membranes by Electrochemical Cyclic Voltammetry as Highly Sensitive Flexible SERS Substrate for On-Site Analysis

The development of high-quality flexible surface-enhanced Raman spectroscopy (SERS) substrates is crucial for developing rapid SERS analysis in situ. Silver nanowire membranes as novel flexible substrates could benefit from the high collection efficiency of analytes by wrapping complex surfaces or wiping the surfaces of samples. However, their low SERS performance impedes further applications of silver nanowire membranes in analyte detection. Herein, we report an ultra-high-sensitivity silver nanowire membrane synthesized by a simple and time-saving cyclic voltammetry (CV) method. After CV treatment, a part of the silver nanowires on the silver nanowire membrane turned into small nanoparticles and nanorods. This nanostructure’s reconstitution increased the analytical enhancement factor of silver nanowire membranes by 14.4 times. Scanning and transmission electron microscopy, UV-vis spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were employed to investigate the transformation in the membrane nanostructure. The CV-treated substrates exhibited high surface-enhanced Raman activity and good temporal stability. The limits of detection (LODs) for p-aminothiophenol, crystal violet, tetramethylthiuram disulfide, sodium perchlorate, malachite green, fluoranthene, and potassium nitrate are 3.7 × 10−12 M, 5.1 × 10−11 M, 5.4 × 10−11 M, 6.3 × 10−9 M, 0.00693 ng, 0.0810 ng, and 0.0273 ng on this substrate, respectively. Additionally, the developed substrate is feasible for the detection of crystal violet in real samples. These results certify that CV-treated substrates possess broad application prospects in on-site SERS analysis.

CHANGE IN THE QUANTITATIVE CONTENT OF DIENE CONJUGATES IN THE ORAL FLUID IN RATS UNDER THE EXPOSURE OF TETRAMETHYLTHIURAM DISULFIDE

Целью исследования было установить уровень диеновых конъюгатов в ротовой жидкости при интоксикации тетраметилтиурамдисульфидом. В результате было установлено, что на 28 сутки был выявлен наибольший токсический эффект ТМДТ, который превысил контрольные значения в 4 раза (400%). Концентрация ДК на 7, 14, 21 сутки возросла на 158,3%, 225,0%, 258,3% соответственно. Полученные результаты говорят о накоплении продуктов перекисного окисления липидов диеновых конъюгатов с увеличением сроков пестицидной интоксикации. The aim of the study was to determine the level of diene conjugates in the oral fluid during tetramethylthiuram disulfide intoxication. As a result, it was found that on day 28, the greatest toxic effect of TMDT was detected, which exceeded the control values by 4 times (400%).. The concentration of DC on days 7, 14, and 21 increased by 158.3%, 225.0%, and 258.3%, respectively. The results obtained indicate the accumulation of lipid peroxidation products of diene conjugates with an increase in the duration of pesticide intoxication.

Influence of the fungicide TMTD as a stress factor on the ultrastructure of pea (Pisum sativum L.) symbiotic nodules

The negative effects of tetramethylthiuram disulfide (TMTD) on the ultrastructural organization of nodules of pea wild-type line SGE were studied.

Analysis of thiram derivatives use in plant complex of the Kursk region

The impact on the biosphere of anthropogenic factors is a serious environmental problem. Today, pesticides are becoming one of the important chemical factors that cause adverse environmental changes. Pesticides enter the human body through a contaminated hydrosphere, atmosphere, and food. Modern man is not able to grow and maintain crops without the use of pesticides. Penetrating into the human body, they cumulate, thereby contributing to the creation of threatening health situations. Despite this, modern human civilization cannot do without them. The purpose of the review was to study the circulation volume of derivatives of thiram, such as vitalon, vitavaks, vitasil, vitaros, tir and TMTD (Tetramethylthiuram Disulfide) in the agricultural complex of the Kursk region for the period 2007-2016. The data obtained at the Kursk Regional Plant Protection Station, as well as agrochemical protection station Kurskaya, were subjected to statistical analysis using the application Statistica 6.0. Circulating volumes of thiram's derivatives were examined in agro-industrial complex of Kursk area over a 10-year period. The proportion of fungicides of thiram's series with the release of agrochemicals dominant in the structure of seed crops cultivation technologies was investigated. A study of the structure of sown areas with the allocation of priority crops grown in the region was conducted, the total number of which amounted 80.76%. The ranking of the region by thirams derivatives was made. All studied fungicidal products of thiram are widely used for the cultivation of crops in the Kursk region. Identified regions with the biggest amount of making this group of agrochemicals in the soil are treated as high anthropogenic load zone and require the development of environmental protection. The volume of circulation of the studying group of pesticides can be dangerous to humans and animals, influence the formation of peoples somatic pathologies.

Thermal and mechanical behavior of SBR/devulcanized waste tire rubber blends using mechano–chemical and microwave methods

The engagement of waste tires rubber as source of raw materials for different applications can be a partial solution to the great environmental problems caused by these products. In this study, waste tire rubber was devulcanized using both mechano–chemical and microwave methods. This process was achieved using different concentrations of 2-mercapto benzothiazole disulfide (MBTS) and tetramethylthiuram disulfide (TMTD) as a devulcanizing agent and different microwave devulcanizing times. The optimum content of both MBTS, TMTD and suitable microwave treatment time to make continuous film were noted. The devulcanized waste rubber was then added, at different concentrations, to virgin styrene–butadiene rubber (SBR). The thermal properties and dynamic mechanical behaviors were investigated for all blends. The thermal analysis proved that natural and styrene butadiene rubber are the main two constituents of the waste tire rubber utilized in this study. The mechanical behavior of the SBR blends remarkably improved by using 20 phr waste rubber (WR) devulcanized by 2 phr MBTS and by exposure for 2.2 min to microwaves. Storage modulus, tearing strength and tension set behaviors notably improved for all SBR/WR blends by irradiating with gamma ionizing radiation with a dose of 100 kGy and further improvement could be attained by increasing the dose up to 200 kGy.

Influence of iron ore concentrate (magnetite) on the kinetics of butadiene–styrene rubber-based blend curing in the presence of different accelerators

Objectives. To investigate the possibility of using a cheaper ingredient, such as magnetite, in the synthesis of rubber compounds based on butadiene–styrene rubber by examining its effect on the process of sulfuric vulcanization of butadiene–styrene rubber in the presence of various accelerators.Methods. The influence of magnetite on the vulcanization kinetics was studied using an Alpha Technologies PRPA 2000 rotorless rheometer. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed using a Mettler Toledo TGA/DSC 2 device to evaluate the effect of magnetite on the butadiene–styrene rubber-based vulcanizates’ oxidation.Results. Magnetite was found to affect the kinetics of SBR-1500 butadiene–styrene rubber sulfuric vulcanization in the presence of thiazole-type accelerators (2-MBT, 2-MBS); in contrast, magnetite was inactive in the case of diphenylguanidine, sulfenamide T, and tetramethylthiuram disulfide. The obtained TGA/DSC data showed that magnetite has no significant effect on the butadiene–styrene rubber-based vulcanizates’ oxidation and thermal destruction.Conclusions. The obtained data confirmed magnetite’s capability to act as a butadiene–styrene rubber sulfuric vulcanization activator in the presence of various accelerators. The most significant effect was observed in the presence of thiazole-type accelerators.

The Fungicide Tetramethylthiuram Disulfide Negatively Affects Plant Cell Walls, Infection Thread Walls, and Symbiosomes in Pea (Pisum sativum L.) Symbiotic Nodules

In Russia, tetramethylthiuram disulfide (TMTD) is a fungicide widely used in the cultivation of legumes, including the pea (Pisum sativum). Application of TMTD can negatively affect nodulation; nevertheless, its effect on the histological and ultrastructural organization of nodules has not previously been investigated. In this study, the effect of TMTD at three concentrations (0.4, 4, and 8 g/kg) on nodule development in three pea genotypes (laboratory lines Sprint-2 and SGE, and cultivar ‘Finale’) was examined. In SGE, TMTD at 0.4 g/kg reduced the nodule number and shoot and root fresh weights. Treatment with TMTD at 8 g/kg changed the nodule color from pink to green, indicative of nodule senescence. Light and transmission electron microscopy analyses revealed negative effects of TMTD on nodule structure in each genotype. ‘Finale’ was the most sensitive cultivar to TMTD and Sprint-2 was the most tolerant. The negative effects of TMTD on nodules included the appearance of a senescence zone, starch accumulation, swelling of cell walls accompanied by a loss of electron density, thickening of the infection thread walls, symbiosome fusion, and bacteroid degradation. These results demonstrate how TMTD adversely affects nodules in the pea and will be useful for developing strategies to optimize fungicide use on legume crops.