Diene Rubber Research Articles

Development of Novel Magnetic Responsive Intelligent Fluid, Hybrid Fluid (HF), for Production of Soft and Tactile Rubber

For the purpose of the replacement of Magnetic Fluid (MF) which is effective in the production of an artificial soft and tactile skin for the robot, etc. by utilizing a rubber solidification method with electrolytic polymerization, we proposed a novel magnetic responsive intelligent fluid, Hybrid Fluid (HF). HF is structured with water, kerosene, silicon oil having Polydimethylsiloxane (PDMS) and Polyvinyl Alcohol (PVA) as well as magnetic particles and surfactant. The state of HF changes as jelly or fluid by their rates of the constituents and motion style. In the present paper, we presented the characteristics of HF: the viscosity and the magnetization are respectively equivalent to those of other magnetic responsive fluids, MF and their solvents. For the structure, HF is soluble simultaneously with both diene and non-diene rubbers. The diene rubber such as Natural Rubber (NR) or Chloroprene (CR) has a role in the feasibility of electrolytic polymerization and the non-diene rubber such as silicon oil rubber (Q) has a role in defense against deterioration. Therefore, the electrolytically polymerized HF rubber by mixing NR, CR as well as Q is effective for the artificial soft and tactile skin. It is responsive to pressure and has optimal property on piezoelectricity in the case of the mixture of Ni particles as filler. HF is effective in the production of the artificial soft and tactile skin made of rubber.

КОНФИГУРАЦИОННО-ИЗОМЕРНЫЙ СОСТАВ КАУЧУКОВ: ОПРЕДЕЛЕНИЕ МЕТОДОМ СПЕКТРОСКОПИИ ЯМР 1H И 13C

Nuclear magnetic resonance (NMR) spectroscopy is a convenient method for studying the structure and isomeric composition of diene rubbers. A simple and reproducible method is proposed for determining the content of both rubber and impurity compounds, which does not require additional sample preparation. Formulas for calculating the composition of industrial products and determining the initial substances are given, the applicability of the analysis method is confirmed. In the process of work, rubbers of various brands were analyzed, their configuration-isomeric composition was established. It was found that the integration ranges given in the literature earlier and the methods for processing 1H NMR spectra differ, the signals of the groups often overlap in the spectrum, which increases the calculation error. It is shown that the structure of the industrial products under study is established most accurately by carbon proton resonance spectroscopy, and the calculation based on the PMR spectra allows confirming the data obtained with sufficient accuracy.

Preservation of geochemical markers during co-combustion of hard coal and various domestic waste materials

Combustion of domestic waste for heating purposes in non-adapted furnaces is a common environmental problem all over the world since it leads to significant emission of harmful substances to the atmosphere. In this project fly and bottom ash from hard coal and domestic waste co-combustion were investigated on the occurrence and distribution of geochemical markers, polycyclic aromatic hydrocarbons (PAHs), and their alkyl derivatives. Hard coal with a domestic waste admixture (paper, ethylene propylene diene rubber, tire rubber, polyethylene, polyvinyl chloride) was combusted in a certified domestic central heating furnace equipped with a control and measurement system. Fly ash was collected on glass microfiber filters inside the flue gas chimney. Raw fuels, fly and bottom ash extracts were analyzed with gas chromatography–mass spectrometry (GC–MS). Geochemical markers survived the coal/domestic waste combustion and can be identified despite the presence of other organic compounds derived from domestic waste thermal decay. The highest changes in distribution and values of geochemical ratios concern light-weight compounds, i.e. lighter n-alkanes and acyclic isoprenoids (pristane and phytane), with distinct differences between fly and bottom ash. n-Alkanes expulsion significantly decreased values of Pr/n-C17 and Ph/n-C18 ratios. Due to their high molecular weight pentacyclic triterpanes mostly retained their original distributions; however, some shifts in values of their thermal maturity ratios occurred due to artificial maturation of organic matter under the heat of combustion. PAHs diagnostic ratios showed variable utility in the indication of domestic waste admixture to hard coal combusted. The highest sensitivity was found for BaP/BghiP, MPI-1, and MPI-3 whereas Fl/(Fl + Py) rather pointed out at hard coal dominating in the fuel mixture. The addition of EPDM and tires significantly worsened the quality of combustion, which is reflected in high extract yields and the retained hard coal geochemical features such as the Pr/Ph value closest to the raw coal value.

Ablation and thermal properties of ethylene propylene diene rubber/carbon fiber composites cured by ionizing radiation for heat shielding applications

In this study, new composites were prepared from ethylene propylene diene rubber (EPDM) that loaded with various concentrations of short carbon fibers (SCFs) ranged from 5 up to 20 part per hundred part of rubber (phr). Aluminum trihydroxide (ATH) was added by two concentrations, namely 10 and 30 phr to EPDM/SCFs composites to enhance its heat shielding. Foaming agent, azodicarbonamide (ADC) was added to increase ablation resistance. Composites were prepared on open rubber roll mills, and then the rubber composites were gamma ray irradiated at different doses of 25, 50, 75, 100 and 150 kGy. Fiber incorporation into rubber matrix has been proven as a key factor in enhancing tensile strength and flame retardant properties of fabricated composites. The prepared composites were characterized by using various analytical methods counting physico-mechanical properties, thermal gravimetric analysis (TGA), Ablation test (oxy acetylene test) and propagation flame test. The utmost mechanical performance was reported for the incorporated 5 phr of carbon fiber into EPDM at 100 kGy. Also, the flame retardancy and ablation properties for composites were enhanced by increasing addition of carbon fibers and ATH in presence of ADC.

Regulation on dual-interface of core–shell dispersed phases and mechanical properties of PP blends by rotary evaporation-assisted melt grafted EPDM-g-MAH

In this study, a series of maleic anhydride-grafted ethylene–propylene–diene rubbers (EPDM-g-MAHs) with different grafting degrees were prepared via the rotary evaporation-assisted melt grafting, which could achieve higher grafting rate and smaller gel content than the traditional melt grafting under the same conditions. Morphological observation, thermal analysis, and rheological measurements confirmed that the interfacial compatibility of the core–shell dispersed phases was enhanced by increasing the composition ratio of EPDM-g-MAH/EPDM or the grafting degree of the prepared EPDM-g-MAHs in the polypropylene (PP) blends. A remarkable improvement in toughness and a little loss in strength and modulus were obtained in the PP blends by regulating the dual interfaces of the core–shell dispersed phases. A new insight into the toughening mechanism of core–shell particles was presented in this work. The balance between toughness and strength could be attributed to the strong dual interfacial interaction of the core–shell dispersed phases, thereby effectively transferring stress. In addition to the conventionally internal cavitation in the rubber phase and the shear yielding of the PP matrix triggered by stress-concentrated dispersed phases, expanded stress field, elongated core phases, and increased cavitation that occurred at dual interfaces by debonding were regarded to contribute to the toughening effect.

The Effect of Compatibilizer on the Mechanical Properties and Compression Set of NBR/EPDM Composite

The mechanical properties of the materials are important to be studied to get the usage information of the material. The NBR/EPDM (Nitrile Butadiene Rubber/Ethylene Propylene Diene Rubber) composite is widely used as seal, gasket, and hose because of their excellent properties. This research used compatibilizer in the blending process of NBR/EPDM. This research aimed to study the effect of some compatibilizer on the mechanical properties and compression set of the NBR/EPDM composite. The compatibilizers used in this research were methyl-methacrylate-butadiene-styrene (MBS), montmorillonite (MMT), and silica. The hardness, tensile strength, elongation at break, tear strength, and compression set of the composites were studied using hardness tester, tensile strength tester, and compression set tester. The research showed that montmorillonite as compatibilizer gave the best hardness, tensile strength, tear strength, elongation, and compression set. The aging increased the hardness and the compression set of NBR/EPDM. However, the aging decreased the tensile strength, tear strength, and elongation at break of NBR/EPDM. Montmorillonite was a suitable compatibilizer for improving the mechanical properties and compression set of NBR/EPDM composite

Development of novel elastomeric blends derived from chlorinated nitrile rubber and chlorinated ethylene propylene diene rubber

Chlorinated nitrile rubber (Cl-NBR) has been blended with chlorinated ethylene propylene diene rubber (Cl-EPDM) in different ratios by a conventional mill mixing method. The effect of the blend ratio on processing characteristics, mechanical properties (such as tensile and tear strength, elongation at break, hardness, abrasion resistance, heat build-up and resilience), structure, morphology, glass transition temperature (Tg), thermal stability, flame retardancy, oil resistance, AC conductivity, dielectric properties and transport behavior of petrol, diesel and kerosene were investigated. The shift in absorption bands of blends studied from FTIR spectra, single Tg from DSC analysis and decrease in amorphous nature from XRD showed the molecular miscibility in Cl-NBR/Cl-EPDM blends. SEM images showed the uniform mixing of both Cl-NBR and Cl-EPDM in a 50/50 blend ratio. The TGA curves indicated the better thermal stability of the polymer blend. The elongation at break, heat build-up, resilience and hardness of the polymer blend decreases with an increase in Cl-NBR content in the blend whereas the flame and oil resistance were increased with increase in Cl-NBR content. Among the polymer blends, the maximum torque, tensile strength, tear and abrasion resistance was obtained for the 50/50 blend ratio because of the effective interfacial interactions between the blend components. AC conductivity and dielectric properties of polymer blend increased with increase in the ratio of Cl-NBR in the blend. Different transport properties such as diffusion, permeation and sorption coefficient were measured with respect to nature of solvent and different blend ratios. Temperature dependence of diffusion was used to estimate the activation parameters and the mechanism of transport found to be anomalous.

Micromechanics of Stress-Softening and Hysteresis of Filler Reinforced Elastomers with Applications to Thermo-Oxidative Aging.

A micromechanical concept of filler-induced stress-softening and hysteresis is established that describes the complex quasi-static deformation behavior of filler reinforced rubbers upon repeated stretching with increasing amplitude. It is based on a non-affine tube model of rubber elasticity and a distinct deformation and fracture mechanics of filler clusters in the stress field of the rubber matrix. For the description of the clusters we refer to a three-dimensional generalization of the Kantor–Webman model of flexible chain aggregates with distinct bending–twisting and tension deformation of bonds. The bending–twisting deformation dominates the elasticity of filler clusters in elastomers while the tension deformation is assumed to be mainly responsible for fracture. The cluster mechanics is described in detail in the theoretical section, whereby two different fracture criteria of filler–filler bonds are considered, denoted “monodisperse” and “hierarchical” bond fracture mechanism. Both concepts are compared in the experimental section, where stress–strain cycles of a series of ethylene–propylene–diene rubber (EPDM) composites with various thermo-oxidative aging histories are evaluated. It is found that the “hierarchical” bond fracture mechanism delivers better fits and more stable fitting parameters, though the evolution of fitting parameters with aging time is similar for both models. From the adaptations it is concluded that the crosslinking density remains almost constant, indicating that the sulfur bridges in EPDM networks are mono-sulfidic, and hence, quite stable—even at 130 °C aging temperature. The hardening of the composites with increasing aging time is mainly attributed to the relaxation of filler–filler bonds, which results in an increased stiffness and strength of the bonds. Finally, a frame-independent simplified version of the stress-softening model is proposed that allows for an easy implementation into numerical codes for fast FEM simulations

Flexible MXene/EPDM rubber with excellent thermal conductivity and electromagnetic interference performance

In this study, a rubber composite was prepared based on two-dimensional (2D) material (MXene) and ethylene propylene diene rubber (EPDM). The MXene was efficiently prepared by etching Ti3AlC2 powder with LiF-HCl solution and subsequent vacuum drying, and the dispersion of MXene in EPDM was improved by optimizing the grinding process, ultrasonic stripping and stirring method. In the process of exploring the electrical conductivity of this material system, the composite exhibits low percolation threshold of 2.7 wt%, a high conductivity of 106 Sm−1 and superior thermal conductivity of 1.57 W/m K at the MXene content of 6 wt%. In addition, MXene (6 wt%)/EPDM with 0.3-mm thick exhibits an EMI shielding performances (SE) up to 48 dB in the X-band (8.2–12.4 GHz) and 52 dB in the Ku-band (12.4–18 GHz) (SE) which are much better than the electromagnetic shielding properties of other rubber blends, and these properties indicate MXene/EPDM composite has great potential for versatile applications.

Synergistic Effects of Amine‐Containing Antioxidants on the Aging Performances of Ethylene Propylene Diene Rubber

AbstractIn this study, two types of amine‐containing antioxidants composed of 2‐mercaptobenzimidazole zinc (MBZ) and 4,4′‐bis(α, α‐dimethylbenzyl) diphenylamine (445) were used to improve the thermo‐oxidative aging resistance of ethylene propylene diene rubber (EPDM). The synergistic effects on the performances of EPDM and the corresponding aging mechanism were investigated by FTIR, tensile test, differential scanning calorimetry (DSC), rotary rheometer and other equipment. The results showed that the hardness increased gradually with the increasing aging time regardless of the type of antioxidants. Compared with the EPDM without antioxidants, the elongation retention of those samples with MBZ or 445 improved obviously. Additionally, the sample with the MBZ/445 complex showed the highest retention values at the same aging time. The antioxidative mechanisms were further analyzed by carbonyl index, activation energy and oxidation induction time, respectively. Results indicated that the degree of oxidation of EPDM using the MBZ/445 complex was much lower than other control systems during the aging process. As a result, the MBZ/445 complex was a favorable antioxidative additive for EPDM.

Stretchable conductors of multi-walled carbon nanotubes (MWCNTs) filled thermoplastic vulcanizate (TPV) composites with enhanced electromagnetic interference shielding performance

Stretchable conductors of multi-walled carbon nanotubes (MWCNTs) filled thermoplastic vulcanizate (TPV) based on polypropylene(PP)/ethylene-propylene -diene rubber (EPDM) blends were fabricated via a simple melt compounding method. MWCNT particles could be selectively distributed in PP matrix induced by the dynamic vulcanization reaction occurred firstly. And the dispersion state of MWCNTs can be improved via increasing the constituent ratio of PP and EPDM. TPV composites with a constituent ratio of 50: 50 wt% exhibits a tiny increase of gauge factor (GF) even up to 100% strain loading, showing a good potential to be used as highly stretchable conductors. Meanwhile, comparing with thermoplastic elastomer (TPE) composites fabricated by the same processing, these TPVs exhibits a lower percolation threshold, enhanced electromagnetic interference (EMI) performance and balanced mechanical performance. Thus, this work provides a simple and scalable melt compounding approach to fabricate highly stretchable conductors with high EMI shielding.

Automotive applications of thermoplastic vulcanizates

AbstractThermoplastic vulcanizates (TPVs) are special classes of thermoplastic elastomers, in which dynamic vulcanization of the rubber phase takes place during melt mixing with a semicrystalline thermoplastic matrix phase at elevated temperature. This review article focus on the different types of thermoplastic vulcanizates (TPVs) from various elastomer and thermoplastic blends that are suitable for the automotive applications purpose. A detailed study of the various TPVs based on polypropylene‐ethylene propylene diene rubber (PP‐EPDM) and polypropylene‐ethylene α‐olefin has been focused and their application in the automobile sector has been summarized. Most of the commercially available TPVs are PP‐EPDM based. Limited applications of that TPVs in high heat and oil resistant application purposes requires new generation of TPVs. High performance TPVs or super TPVs are new generation TPVs that exhibit high heat resistance as well as excellent oil resistance property suitable for automotive under‐the‐hood applications. Therefore TPVs based on XNBR‐PA12, HNBR‐PA12 and FKM‐PA6 system has also been explored in details in this study and the possibility of the use of those TPV system has been focused for the high temperature application purpose in the automobile sector where high and oil resistant application properties is the prime concern.

Construction Sealants Based on EPDM Modified with Silane-Terminated Urethane Prepolymers

In connection with the use of new materials and structures in construction, the issue of developing sealing materials for construction purposes with an improved set of properties remains relevant. In particular, sealing materials based on ethylene propylene diene rubber (EPDM) are promising due to their resistance to UV radiation, ozone, and the absence of cold flow. The paper shows the possibility of obtaining reactive sealants based on EPDM and silane-terminated prepolymers - STP based on oligotetraoxymethylene glycol (polyfurite) and based on oligooxypropylene glycol (laprol). The use of prepolymers leads to an increase in the cohesive and adhesive strength of the sealing compositions, while maintaining the cohesive nature of the fracture. Also, the obtained sealants are more technological, since they have a lower viscosity under processing conditions. Extensive tests of reactive sealants based on EPDM have shown that after aging it has a higher level of properties compared to sealants without STP.

Modification of Compounds Based on Ethylene–Propylene–Diene Rubbers Using an Oligomeric Unsaturated Polyketone

The efficiency of using an oligomeric unsaturated polyketone prepared by ketonization of cis-1,4-butadiene rubber with nitrogen(I) oxide (N2O) for the modification of physicomechanical properties of elastomer compounds based on Keltan 512 and SKEPT-50 ethylene–propylene–diene rubbers was demonstrated. The modification leads to a decrease in the viscosity of filled rubber stocks, facilitating their processing on the process equipment, and to more uniform dispersion of the silica filler (BS-1290 white soot); it enhances the elastic and strength characteristics of the vulcanizates by a factor of up to 2–2.5 relative to the unmodified compounds.

Reaction mechanism of halogenated rubber crosslinking using a novel environmentally friendly curing system

Iron (III) acetylacetonate (Fe (acac)) in the presence of triethanolamine (TEOA) was utilized as a novel crosslinking agent for halogenated diene rubber. Following the assumption that the mechanism of the crosslinking bases on the Heck-type reaction mechanism, which requires the presence of a halogen and an unsaturated carbon-carbon double bond, chloroprene rubber (CR) and brominated butyl rubber (BIIR) were utilized as rubber matrices. The results of FTIR spectra analysis confirm the proposed mechanism and indicate that a Heck-type reaction is feasible for performing a crosslinking of halogenated diene rubbers. The use of the Fe (acac)/TEOA curing system results in a significant torque increase during the vulcanization, which confirms the high activity of those compounds. The elimination of halogen from a rubber macromolecular structure or elimination of a basic environment of the crosslinking reaction results in a deactivation of the new curing system.

Влияние 0d и 2d наноуглеродов на свойства резин на основе диеновых эластомеров

Влияние 0d и 2d наноуглеродов на свойства резин на основе диеновых эластомеров

Advances in Synthesis of Ethylene–Propylene–Diene Elastomers by Ion-Coordination Polymerization on Single-Site Catalytic Systems of New Generation

The studies devoted to the synthesis of ternary copolymers of ethylene, propylene, and nonconjugated cyclic dienes on single-site catalytic systems of a new generation based on metallocene complexes, “constrained geometry” complexes, and monocyclopentadienyl and post-metallocene chelate IVB-group complexes have been analyzed. The advantages and disadvantages of these catalytic systems have been compared with traditional vanadium catalysts introduced into production in the 1960s and used to date in the industrial synthesis of rubbers. A significant part of the review is devoted to the analysis of patent publications, especially in recent years, belonging to the main world producers of ethylene–propylene–diene rubbers.

Calculation of permissible monomer conversion in cascade polymerizers during the synthesis of general-purpose rubbers

The generalized model of combined chemical transformation and heat exchange is represented by a set of equations of the thermal balance and initial moments of MWD in stationary mode. A mathematical model of production process of synthesis of diene rubber on cobalt-based catalytic system consisting of kinetic and energy module is developed. The calculation algorithm of mathematical model of technological process of production of rubber SRDC on the basis of which numerical experiments are carried out is offered. The maximum permissible conversions are calculated. The influence of the initiator concentration, monomer and the temperature of the cascade input flow on the temperature of the cascade reactors and the conversion is researched.

Crosslinking diene rubbers by using an inverse vulcanised co-polymer

A green approach is explored in crosslinking diene rubbers by using an inverse vulcanised co-polymer of sulfur and styrene.

Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene–propylene–diene rubber

Diffusion and sorption of five gases (H2, N2, O2, CO2, CH4) in hydrogenated nitrile butadiene rubber (HNBR) and ethylene–propylene–diene rubber (EPDM) have been investigated by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The diffusion coefficients of gas molecules in HNBR and EPDM are well correlated with the effective penetrant diameter except for CO2. CO2 shows a lower diffusion coefficient due to its linear shape. Additionally, the favorable interaction between CO2 and HNBR is another factor for its lower diffusion coefficient in HNBR. HNBR shows lower diffusion coefficients than EPDM. This is because the polar –CN groups in HNBR chains increase interchain cohesion and result in tight intermolecular packing, low free volume and poor chain mobility, which decreases the diffusion coefficients of HNBR. The solubility coefficients of CH4, O2, N2 and H2 in HNBR are lower than those in EPDM, which is a result of the weak HNBR–penetrant interactions and low free volume of HNBR. However, the solubility coefficient of CO2 in HNBR is higher than in EPDM. This is attributed to the strong interaction between CO2 and HNBR. H2, O2, N2 and CH4 show lower permeability coefficients in HNBR than in EPDM, while CO2 has higher permeability coefficients in HNBR. These molecular details provide critical information for the understanding of structures and gas transport between HNBR and EPDM.