Diphenylguanidine Research Articles

Accelerated aging of tire and road wear particles by elevated temperature, artificial sunlight and mechanical stress — A laboratory study on particle properties, extractables and leachables

Tire and road wear particles (TRWP) are generated in large quantity by automobile traffic on roads but their way of degradation in the environment is largely unclear. Laboratory experiments were performed on the effect of elevated temperature (simulating 2–3 years), sunlight exposure (simulating 0.5 years) and mechanical stress on the physical properties and chemical composition of TRWP and of cryo-milled tire tread (CMTT). No significant effects were observed of the applied mechanical stress on mean properties of pristine particles. After sunlight exposure up to 40 % in mass were lost from the TRWP, likely due to the loss of mineral incrustations from their surface. The chemical composition of TRWP and CMTT was characterized by determining 27 compounds, antioxidants (phenylene diamines), vulcanization agents (benzothiazoles and guanidines) and their transformation products (TPs). Extractables of TRWP (580–850 μg/g) were dominated by TPs, namely benzothiazolesulfonic acid (BTSA). CMTT showed much higher amounts of extractables (4600 μg/g) which were dominated by parent chemicals such as N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6-PPD), diphenylguanidine (DPG) and mercaptobenzothiazole (MBT). Sunlight exposure affected the amount of extractables more strongly than elevated temperature, for TRWP (−45 % vs −20 %) and CMTT (−80 % vs −25 %) and provoked a clear shift from parent compounds to their TPs. After sunlight exposure extractables of TRWP were dominated by BTSA and DPG. Sunlight exposure drastically reduced the 6-PPD amount extracted from both, TRWP and CMTT (−93 %, −98 %), while its quinone (6-PPDQ) increased by around 1 % of the 6-PPD decrease, only. For many TPs, concentration in leachates were higher than in extracts, indicating ongoing transformation of their parent compounds during leaching. These results highlight that abiotic aging of TRWP leads to strong changes in their chemical composition which affect their particle properties and are of relevance for the environmental exposure to tire-related chemicals.

A new deep eutectic solvent based on diphenylguanidine for the effective extraction of pertechnetate anion

In this work, for the first time, a new class of deep eutectic solvents has been synthesized and applied for the efficient extraction of pertechnetate anion from imitators of real media from which pertechnetate removal is needed: high-level waste imitator and sea water imitator. Diphenyl guanidine was studied as a hydrogen bond acceptor, which exhibits a high extraction ability for pertechnetate anion separation. Natural fatty acid and natural terpene were studied as hydrogen bond donors. The structure, properties, viscosity and stability of the obtained eutectic solvents were studied. Also, the radiation resistance of the obtained solvents was studied from the point of view of distribution ratio saving. It was shown that the new class of solvents has a high radiation resistance and efficiently extracts pertechnetate anion even from acidic media in high-temperature extraction process and can be the first step platform for solving technological and radiation safety problems.

Phosphonium Ionic Liquid-Activated Sulfur Vulcanization: A Way Forward to Reduce Zinc Oxide Levels in Industrial Rubber Formulations.

Extensive use of zinc oxide and accelerators such as diphenyl guanidine (DPG) in the vulcanization of rubber composites entail potential environmental risks. These are pervasive contaminants of roadway runoff originating from tire wear particles (TWPs). Herein, the effect of phosphonium ionic liquids (PILs) in styrene-butadiene rubber compounds was demonstrated with reduced ZnO loading and no DPG to minimize the environmental footprint of the vulcanization process. The structure and chemistry of PILs were found to be the influencing parameters impelling the cross-linking kinetics, enabling shorter induction times. The generation of active Zn2+ sites by PILs was examined through FTIR spectroscopy, calorimetry, and molecular dynamics simulations. From a tire application perspective, the PILs not only enhanced the cure kinetics but also improved the dynamic-mechanical behavior of the rubber composites. Consequently, the harm caused by TWPs to the atmosphere, fuel intake, and CO2 emissions was minimal, thereby confirming the potential use of PILs in the tire industry.

Degradation by Electron Beam Irradiation of Some Elastomeric Composites Sulphur Vulcanized.

Composites based on natural rubber and plasticized starch obtained by the conventional method of sulfur cross-linking using four types of vulcanization accelerators (Diphenyl guanidine, 2-Mercaptobenzothiazole, N-Cyclohexyl-2-benzothiazole sulfenamide, and Tetramethylthiuram disulfide) were irradiated with an electron beam in the dose range of 150 and 450 kGy for the purpose of degradation. The vulcanization accelerators were used in different percentages and combinations, resulting in four mixtures with different potential during the cross-linking process (synergistic, activator, or additive). The resulting composites were investigated before and after irradiation in order to establish a connection between the type of accelerator mixture, irradiation dose, and composite properties (gel fraction, cross-linking degree, water absorption, mass loss in water and toluene, mechanical properties, and structural and morphological properties). The results showed that the mixtures became sensitive at the irradiation dose of 300 kGy and at the irradiation dose of 450 kGy, and the consequences of the degradation processes were discussed.

Выбор ускорителей вулканизации для резин на основе эпихлоргидринового каучука

The effect of vulcanization accelerators on the structure and properties of rubbers based on Hydrin T6000 epichlorohydrin rubber has been studied. Mercaptobenzthiazole (MBT) in the amount of 1.5 pts.wt., tetramethylthiuram disulfide (TMTD) — 0.5 – 1.5 pst.wt. were used as accelerators and N,N’-diphenylguanidine (DPG) — 0.5 – 1.5 pst.wt., which represent a triple system of accelerators. The choice of accelerators is based on the possibility of obtaining a vulcanization spatial structure of different sulfide content: thiuram group accelerators promote the formation of mono-, disulfide bonds; guanidine — polysulfide bonds, and thiazole groups — from carbon-carbon to polysulfide with varying degrees of sulfide. According to the results of the study of physical and mechanical properties, the determination of the parameters of the spatial grid and the study of the dynamic behavior of rubber, differences were revealed due to the formation of a spatial structure with different types of cross-links and density. It is shown that rubber containing 1.5 pst. wt. MBT, 0.5 pst. wt. DFG and 0.5 – 1.0 pst.wt. TMTD due to the manifestation of a synergistic effect on the formation of a vulcanization network of a certain density and the ratio of poly-, di- and monosulfide cross-links. Thus, the use of a group of accelerators with different functional effects makes it possible to obtain vulcanizates with an optimal set of technological and operational properties.

Uptake, Metabolism, and Accumulation of Tire Wear Particle-Derived Compounds in Lettuce.

Tire wear particle (TWP)-derived compounds may be of high concern to consumers when released in the root zone of edible plants. We exposed lettuce plants to the TWP-derived compounds diphenylguanidine (DPG), hexamethoxymethylmelamine (HMMM), benzothiazole (BTZ), N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), and its quinone transformation product (6PPD-q) at concentrations of 1 mg L-1 in hydroponic solutions over 14 days to analyze if they are taken up and metabolized by the plants. Assuming that TWP may be a long-term source of TWP-derived compounds to plants, we further investigated the effect of leaching from TWP on the concentration of leachate compounds in lettuce leaves by adding constantly leaching TWP to the hydroponic solutions. Concentrations in leaves, roots, and nutrient solution were quantified by triple quadrupole mass spectrometry, and metabolites in the leaves were identified by Orbitrap high resolution mass spectrometry. This study demonstrates that TWP-derived compounds are readily taken up by lettuce with measured maximum leaf concentrations between ∼0.75 (6PPD) and 20 μg g-1 (HMMM). Although these compounds were metabolized in the plant, we identified several transformation products, most of which proved to be more stable in the lettuce leaves than the parent compounds. Furthermore, continuous leaching from TWP led to a resupply and replenishment of the metabolized compounds in the lettuce leaves. The stability of metabolized TWP-derived compounds with largely unknown toxicities is particularly concerning and is an important new aspect for the impact assessment of TWP in the environment.

Supramolecular Design Strategy of a Water-Soluble Diphenylguanidine-Cyclodextrin Polymer Inclusion Complex.

Diphenylguanidine (DPG) is a widely used secondary accelerator for the vulcanization of natural rubber (NR) latex. However, its low water solubility and high toxicity limit its use in high-end NR products. In this study, a water-soluble inclusion complex of DPG and a β-cyclodextrin polymer (β-CDP), termed DPG-β-CDP, was prepared through supramolecular interactions and characterized using Fourier-transform infrared spectroscopy, 1H NMR, scanning electron microscopy, and UV-vis spectroscopy techniques. In comparison with that of DPG, the water solubility of DPG-β-CDP was greatly enhanced because of the water-soluble host molecule. The molar ratio of DPG to the CD unit in β-CDP was determined to be 1:1. At 25 °C, the binding constant of DPG-β-CDP was found to be 9.2 × 105 L/mol by UV-vis spectroscopy. The proposed method for forming inclusion complexes with high potential for use as water-soluble vulcanization accelerators is promising.

Aiming to improve binding of porphyrin diphenyl guanidinium conjugates to guanine-quadruplexes: When size matters

Aiming to improve the binding to Guanine quadruplexes of different topologies, docking studies of porphyrin diphenyl guanidine conjugates previously prepared with an O or a S bridge between the diphenyl moiety and a newly design derivative with an SO2 bridge were carried out using different guanine quadruplexes of different topologies (four parallel, one antiparallel and one hybrid). Positive results were obtained from these computational studies drove us to prepare the SO2 bridge conjugate improving the synthetic route previously reported by us. Biophysical experiments such as UV-thermal melting and circular dichroism indicated the lack of binding to the double stranded DNA and poor binding of the new derivative prepared to any of the guanine quadruplexes studied. These results show that the size of this SO2 bridge could be responsible of the poor experimental binding to guanine quadruplexes.

Occurrence, Distribution, and Environmental Behavior of Persistent, Mobile, and Toxic (PMT) and Very Persistent and Very Mobile (vPvM) Substances in the Sources of German Drinking Water

Persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances have been recognized as a threat to both the aquatic environment and to drinking water resources. These substances are currently prioritized for regulatory action by the European Commission, whereby a proposal for the inclusion of hazard classes for PMT and vPvM substances has been put forward. Comprehensive monitoring data for many PMT/vPvM substances in drinking water sources are scarce. Herein, we analyze 34 PMT/vPvM substances in 46 surface water, groundwater, bank filtrate, and raw water samples taken throughout Germany. Results of the sampling campaign demonstrated that known PMT/vPvM substances such as 1H-benzotriazole, melamine, cyanuric acid, and 1,4-dioxane are responsible for substantial contamination in the sources of German drinking water. In addition, the results revealed the widespread presence of the emerging substances 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and diphenylguanidine (DPG). A correlation analysis showed a pronounced co-occurrence of PMT/vPvM substances associated predominantly with consumer or professional uses and also demonstrated an inhomogeneous co-occurrence for substances associated mainly with industrial use. These data were used to test the hypothesis that most PMT/vPvM substances pass bank filtration without significant concentration reduction, which is one of the main reasons for introducing PMT/vPvM as a hazard class within Europe.

Two-Layer Rubber-Based Composite Material and UHMWPE with High Wear Resistance.

The aim of the study is the development of two-layer materials based on ultra-high-molecular-weight polyethylene (UHMWPE) and isoprene rubber (IR) depending on the vulcanization accelerators (2-mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and tetramethylthiuram disulfide (TMTD)). The article presents the study of the influence of these accelerators on the properties and structure of UHMWPE. It is shown that the use of accelerators to modify UHMWPE leads to an increase in tensile strength of 28–53%, a relative elongation at fracture of 7–23%, and wear resistance of three times compared to the original UHMWPE. It has been determined that the introduction of selected vulcanization accelerators into UHMWPE leads to an increase in adhesion between the polymer and rubber. The study of the interfacial boundary of a two-layer material with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) showed that the structure is characterized by the presence of UHMWPE fibrils localized in the rubber material due to mechanical adhesion.

Original Basic Activation for Enhancing Silica Particle Reactivity: Characterization by Liquid Phase Silanization and Silica-Rubber Nanocomposite Properties.

Silica fillers are used in various nanocomposites in combination with silanes as a reinforcing filler. In tire technology, silica is generally functionalized before (pre-treated) or during mixing (in-situ silanization or post-treated). In both cases, a soft base catalyst (e.g., triethylamine or diphenyl guanidine, DPG) is typically used to accelerate and increase the yield of the silane/silica coupling reaction. In this study, we investigated how pre-treatments of silica particles with either strong amine or hydride bases impact the silanization of silica prior to or during SBR mixing for silica-rubber nanocomposite fabrication. Our findings are supported by molecular characterization (solid state 29Si NMR, 1H NMR and TGA), and scanning electron microscopy. In addition, the impact of these silica pre-treatments on a nanocomposite’s mechanical properties was evaluated using dynamic mechanical analysis (DMA).

Design Strategy for Vulcanization Accelerator of Diphenylguanidine/Cyclodextrin Inclusion Complex for Natural Rubber Latex Foam with Enhancing Performance.

Vulcanization is an essential process to obtain high-performance rubber products. Diphenylguanidine (DPG) is often used as the secondary accelerator in the vulcanization process of natural rubber (NR) latex. However, DPG would make NR latex emulsion exhibit gelation, resulting in the negative vulcanization efficiency. In addition, exposure to DPG might lead to some physiological diseases during the production process of DPG doped NR latex. Hydroxypropyl-β-cyclodextrin (HP-β-CD) with the hydrophobic interior and hydrophilic exterior has the advantages of good water solubility, high bioavailability, reliable stability, and low toxicity. In this study, the inclusion complex of diphenylguanidine-hydroxypropyl-β-cyclodextrin (DPG-HP-β-CD) is prepared by ball milling with a host-guest molar ratio of 1 : 1, which has also been applied to the foaming process of NR latex. The mechanical properties of DPG-HP-β-CD inclusion complex/natural rubber latex foam (DPG-HP-β-CD/NRLF) have been significantly improved, including the tensile strength, elongation at break, hardness, compression set, resilience, and antiaging performance. Further, the usage of DPG has been reduced, leading to the reduction of toxicity and environmental hazards.

Investigation of abiotic degradation of tire cryogrinds

The abundance of microplastics found in the environment is a major cause of concern. Tire tread particles containing additives such as curing accelerators and antioxidants, can be a major source of elastomer pollution in the environment. Such tire particles combined with road pavement particles are referred to as tire and road wear particles, TRWP. The environmental availability from parent elastomers and the release of additives in the process of abiotic degradation were evaluated using freeze-thaw, wet-dry and accelerated UV-weathering experiments. Acceleration factor determination tests were conducted to correlate UV-exposure to the natural aging in the environment. Freeze-thaw testing showed many additives such as diphenyl guanidine (DPG), benzothiazole sulfenamide (BTS) and para-phenylene diamine (6 PPD) as tetrahydrofuran leachates and BTS transformation products. Further, UV exposure equivalent to 1.5 yr., 3 yr. and 5 yr. aging resulted in the formation a combination of ketones and carboxylic acids for styrene butadiene rubber (SBR), natural rubber (NR), and butadiene rubber-based tire cryogrinds. Attenuated total reflectance- Fourier- transform infrared spectroscopy (ATR-FTIR) was used to detect the degradation of the elastomers on UV-exposure while gas chromatography-mass spectroscopy (GC-MS) was used as a nontargeted, suspect screening analysis technique. The degradation intermediates and leachates identified using GC-MS represents useful data for the life cycle analysis of the functional polymers and additives and their possibility of environmental release.

Occurrences of Tire Rubber-Derived Contaminants in Cold-Climate Urban Runoff

Recent findings that 2-anilo-5-[(4-methylpentan-2-yl)amino]cyclohexa-2,5-diene-1,4-dione (6PPD-quinone), the transformation product of a common tire rubber antioxidant, is acutely toxic in stormwater-impacted streams has highlighted the need for a better understanding of contaminants in urban runoff. This study represents one of the first reports of 6PPD-quinone and other tire rubber-derived compounds in stormwater and snowmelt of a cold-climate Canadian city (Saskatoon, 2019–2020). Semiquantification of the five target compounds, N,N′-diphenylguanidine (DPG), N,N-dicyclohexylmethylamine (DCA), N,N′-dicyclohexylurea (DCU), 1-cyclohexyl-3-phenylurea (CPU), and 6PPD-quinone, revealed DPG was most abundant, with average concentrations of 60 μg L–1 in stormwater and 1 μg L–1 in snowmelt. Maximum observed concentrations of DPG were greater than 300 μg L–1, equivalent to loadings of 15 kg from a single rain event. These concentrations of DPG represent some of the highest reported in urban runoff globally. 6PPD-Quinone was detected in 57% (12/21) of stormwater samples with a mean concentration of approximately 600 ng L–1 (2019) and greater than 80% (28/31) of snowmelt samples with mean concentrations of 80–370 ng L–1 (2019 and 2020). Concentrations of 6PPD-quinone exceeded the acute LC50 for coho salmon (0.8–1.2 μg L–1) in greater than 20% of stormwater samples. Mass loadings of all target chemicals correlated well with roads and residential land-use area.

Probing the chemical complexity of tires: Identification of potential tire-borne water contaminants with high-resolution mass spectrometry

Tire wear particles are not only the type of polymer particles most prevalent in the environment but also act as source of various organic micropollutants, many of which are likely still unknown. We extracted particles prepared from nine tires in artificial freshwater (28 d) with the goal to characterize leachables (max intensity >105 in artificial freshwater), which are tire-borne water contaminants. A subsequent extraction of these particles with acetone (3 h) was used to assess the long-term leaching potential. A suspect and nontarget screening in aliquots of each extract led to the detection of 214 organic substances of which 145 were classified as leachables. The intrinsic polarity of some leachables (mean log D (pH 7.4) 3.9), which facilitates an increased aquatic mobility, highlights their potential as environmental water contaminants. With N,N′-diphenylguanidine (DPG) and benzothiazole, two of the ten unequivocally identified leachables, are classified as potential persistent, mobile and toxic substance by the German Environment Agency. Of the identified chemicals DPG showed the highest intensities in aqueous extracts and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6-PPD), the precursor of 6-PPD-quinone, in acetone extracts. A comparison between the 69 detected suspects and 174 high-intensity signals (>106) detected in the nontarget screening led to an overlap of only 29 features. A detailed investigation of the remaining high-intensity suspects revealed the presence of 13 proposed DPG reaction products, further highlighting the chemical complexity of tires. Consequently, we conclude that there are many, often still unrecognized chemicals entering the aquatic environment through leaching from tire wear particles.

Identification of glycerol as a novel accelerator for sulphur vulcanization of unsaturated rubbers

Different organic polyols were investigated as accelerators for different type of vulcanization system such as sulphur, metal oxide, peroxide with different rubbers such as natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), butyl rubber (IIR), nitrile rubber (NBR) and chloroprene rubber (CR). Among all the polyols studied, glycerol found to be the most efficient accelerator for sulphur vulcanization of unsaturated rubbers. Moreover, from rheometric study glycerol was found to be reversion free and scorch safe accelerator. A detailed study was performed with glycerol for sulphur vulcanization of silica filled, SBR + BR-based standard passenger car radial (PCR) tire tread compound and plausible mechanism of acceleration was proposed. Finally, from the PCR tyre tread compound 70% of conventional accelerators, namely N-cyclohexyl-2-benzothiazole sulfenamide (CBS) and di-phenyl guanidine (DPG) were replaced with 5 phr (parts per hundred gram of rubber) of glycerol and properties of the vulcanized compounds were measured. The results evidenced that glycerol could efficiently replace 70% conventional accelerators (CBS + DPG), with additional improvement of scorch time by 68%, tensile strength by 31.5%, elongation at break by 75.6% and tear strength by 9.4% of the PCR tyre tread compound. The increase in mechanical properties was due to the improvement in compatibility between silica and rubber in presence of glycerol. Moreover, glycerol is an environmentally benign (nitrogen free, halogen free), fossil free, low-cost material.

Diphenyl guanidine vulcanization accelerators enable sulfurized polyacrylonitrile cathode for high capacity and ether-compatible by fast kinetic

Sulfurized polyacrylonitrile (SPAN) cathode shows excellent electrochemical performance in carbonate electrolyte for lithium-sulfur batteries. However, the limited redox conversion rate of SPAN cathode in ether electrolyte would lead to high solubility of the intermediate polysulfide Li2Sn(n ≤ 4) and shuttling, resulting in a low performance of corresponding lithium-sulfur battery, even though ether-based electrolytes are more suitable in terms of Li metal anode. In addition, SPAN is comparatively lower sulfur loading (<50 wt%) reduced its value. Improving the sulfur loading and accelerate the redox conversion of SPAN to be compatible with ether electrolyte will be one of the most promising cathode of lithium-sulfur batteries. Here, we introduced a sulfurized polyacrylonitrile cathode (SPAN-DG) with high sulfur loading (52 wt%) and high conductivity prepared by diphenylguanidine as vulcanization accelerator into lithium-sulfur battery based on ether electrolyte. This study found that SPAN-DG cathode with high conductivity can fast reaction kinetics and successfully inhibit the dissolution of lithium polysulfide and shuttle in ether electrolytes, shows good electrochemical performance. SPAN-DG cathode deliver a specific capacity of 879 mAh g−1 and 661 mAh g−1 (based on the mass of cathode) at rates of 0.1C and 1C (1C = 700 mA g−1), respectively.

Relation between activation energy and induction in rubber sulfur vulcanization: An experimental study

AbstractThe article presents the possibility to use the so‐called frequency factors in order to select the optimal temperature to mix rubber blend recipes before vulcanization without inducing premature crosslinking. As secondary result of the research, it provides a very simple approach to evaluate induction assuming a first order kinetic approach. It has been frequently observed that the activation energy in a first order rubber vulcanization scheme appears to be function of the particular activators used and that activation energy links to the so‐called waiting time (and induction) by means of the frequency factor through an exponential relationship. A total of 212 rheometer curves are experimentally obtained and suitably postprocessed, consisting of pure natural rubber (NR), polybutadiene (PB), and 50–50 or 70%–30% NR‐PR blends in presence of different concentrations of sulfur and accelerants (diphenyl guanidine [DPG] and N‐t‐butylbenzothiazole‐sulfenamide [TBBS]). Data reduction is carried out to have an insight into the most suitable temperature to utilize in the different cases in order to: (a) Obtain the best mixed blends without risking premature vulcanization and (b) design the induction phase without over vulcanize the blend and/or delaying curing because the time required is too long. Waiting time and induction are evaluated by means of a well‐established exponential law requiring the knowledge of the activation energy (assuming for the sake of simplicity that crosslinking occurs following a first order reaction kinetic law) and a constant called “frequency factor”. Frequency factor, considering all reactions monomolecular for the sake of simplicity, is assumed of the order of magnitude of 10−13–10−14 s. All experimental data carried out are critically compared and a wide explanation of the expected induction times and most suitable temperatures to use in the mixing phase is provided in the different cases considered. The article provides a meaningful insight into the importance of the link existing among activation energy, vulcanization recipe (with particular regard to concentration of accelerants, blend between two rubbers with very different activation energies and interaction between two accelerants) and mixing temperature to adopt before curing.

Contribution of filler–filler interaction and filler aspect ratio in rubber reinforcement by silica and mica

The reinforcement degree offered by silica as a spherical filler with low aspect ratio and high filler–filler interaction was compared with mica as a platelet filler with higher aspect ratio and lower filler–filler interaction. By replacing half of the carbon black with silica or mica in a typical formulation, rubber composites were prepared and their properties were evaluated under two conditions: In the first one, the impact of increasing the amount of a chemical surface modifier, namely silane TESPT (bis triethoxysilylpropyl tetrasulfide), was investigated and in the second one, the increasing amount of a physical modifier namely DPG (diphenyl guanidine) on the performance of the two fillers was explored. The resulting composites were subjected to physico-mechanical experiments including the bound rubber, tensile test, and the dynamic mechanical thermal analysis (DMTA). Results indicated that the greater amount of filler–filler interaction resulting from the higher SiO2 and hydroxyl content in silica has a dominating role over the aspect ratio of mica which is then led to a remarkable difference in their bound rubber. However, the mica-containing composites were capable of competing with silica when the DPG was used. Nevertheless, the compound only containing carbon black with 19.7 MPa of tensile strength and 24.4 kgf/cm of tear strength showed the best mechanical properties among other fillers, and by replacing 30 phr carbon black, these properties decreased approximately 15 ± 3%. Based on DMTA findings, promising data were obtained for the mica-reinforced rubbers with regard to the tire application.

Diphenyl guanidine as vulcanization accelerators in sulfurized polyacrylonitrile for high performance lithium-sulfur battery

A comparative study on the effect of different vulcanization accelerators on the electrochemical performance of sulfurized polyacrylonitrile cathodes is conducted for the first time. Compared with these vulcanization accelerators, the sulfurized polyacrylonitrile composite prepared by diphenyl guanidine vulcanization accelerator significantly enhances discharge capacity and cycling stability. Diphenyl guanidine dramatically improves the sulfur content by 14 wt%, resulting in a remarkable discharge capacity of 897 mA h gcomposite−1 at a rate of 0.1C (1C = 700 mA g−1) corresponding Li-S batteries, while maintain the outstanding cycling stability. Therefore, diphenyl guanidine can be used as a vulcanization accelerator in the formulation of a high-capacity sulfurized polyacrylonitrile cathodes.