EPDM Research Articles

Time-varying compressive properties and constitutive model of EPDM rubber materials for tunnel gasketed joint

The stress relaxation of ethylene propylene diene monomer (EPDM) rubber material in a compressed state significantly increases the risk of water leakage at tunnel precast segmental joints. Additionally, EPDM rubber gaskets typically experience a complex precompression strain state, further complicating the prediction of long-term stress relaxation. Therefore, it is imperative to propose a novel constitutive model that realistically reflects the stress relaxation of rubber with arbitrary precompression strain, providing a reference for the long-term waterproof design of shield tunnels. In this study, the time-varying properties of EPDM rubber at material level were studied in detail. At first, a comprehensive set of accelerated aging tests were conducted on EPDM rubber samples with varying precompression strains. The hardening effect of rubber without precompression and the stress relaxation effect of rubber with precompression were explored. The time-varying law and mechanism governing rubber properties under these two effects were analyzed. Subsequently, a conversion relationship between the EPDM rubber test conditions and the actual service time was established. The predicted hardening coefficient for uncompressed EPDM after 100 years is 1.468, whereas the relaxation coefficient for compressed EPDM is 0.359. Comparative analysis revealed that the compression set index do not consider the beneficial effects of hardening, resulting in a 54.1% overestimation of the design water pressure. Finally, the analytical study on the constitutive model of EPDM rubber material was carried out. The error in compression curve for unaged sample obtained from empirical formulas exceeded three times that of the analytical model, underscoring the need to study time-varying constitutive models. An interpolation method was employed to extend the test curve, leading to the development of a new constitutive model that represents the stress relaxation characteristics of EPDM materials under arbitrary precompression strain states. By combining the proposed constitutive model with the timetemperature conversion relationship, the time-varying expressions of the constitutive parameters for relaxation and hardening effects during the service life were derived. In comparison with existing models, the proposed model demonstrates wider applicability, effectively captures the time-varying characteristics of EPDM materials under arbitrary precompression strains, offering an efficient approach for studying the long-term stress relaxation prediction of rubber gaskets in shield tunnels under complex precompression strain states.

Impact of ultraviolet aging on the composition and characteristics of multifunctional composite coatings

AbstractMultifunctional composite coatings exposed to environmental conditions are prone to aging and potential functional failure due to ultraviolet (UV) radiation. This study investigates the impact of UV radiation on the structure and properties of low infrared emissivity composite coatings, comprising ethylene propylene diene monomer (EPDM) as the matrix and antistatic carbon fiber (CF) and flaky floating aluminum powder as fillers. In addition to analyzing the photochemical degradation reactions of the composite coating under UV irradiation, the role of fillers in resisting UV aging is elucidated. The performance parameters examined include infrared (IR) emissivity, surface resistivity, mechanical properties, and dielectric properties. The results indicate that after UV aging, EPDM undergoes the most significant changes, leading to the formation of carbonyl groups. CFs experience mild UV aging and an increase in resistivity. Aluminum powder, on the other hand, remains largely unchanged after UV aging and its addition significantly reduces the UV aging rate of the composite coating, resulting in a low IR emissivity of as low as 0.2 after UV aging. Among them, Coating 4 exhibits the best overall performance after UV aging.Highlights The UV aging mechanism of EPDM and the role of fillers were revealed. The UV aging of the coating significantly reduced the infrared emissivity (Reduced from 0.5 to 0.2). Al powder effectively reduced the UV degradation rate of the coating by reflecting UV light. The properties of the double‐formulated coating perform best after UV aging.

A Novel Method to Characterize the Damping Capacity of EPDM/CIIR Blends Using Vibrating Rubber Balls.

An experimental device fixed with a laser displacement sensor was assembled to investigate the rebound behaviors and damping mechanism of rubber balls prepared with ethylene-propylene-diene monomer (EPDM)/chlorinated butyl rubber (CIIR) blends. The result showed that a prediction model was proposed to characterize the damping capacity by using the rebound height of the rubber balls. The lower rebound height corresponded to better damping capacity. A modified equation relating to the rebound height has been obtained from the theoretical derivation on the basis of the dynamic mechanical analysis, showing that the rebound height was affected by the deformation frequency, the external excitation, and the nature of rubber blends. Furthermore, the energy dissipation rate (EDR), defined by the ratio of the height loss to the rebound time, was proposed to further characterize the damping capacity. The EDR value was shown to be highest for the pure CIIR and lowest for the pure EPDM, exhibiting a decreasing trend with the increase in EPDM content in the rubber blends. It can be expected that the damping capacity of the EPDM/CIIR blends decreases with the decrease in external excitation, the conclusion of which plays a key role in the formulation design of viscoelastic damping rubber materials.

Mechanically Robust, Recyclable, and Highly Thermally Conductive Ethylene–Propylene–Diene Monomer/Boron Nitride Composite Enabled by Multiple Interfacial Cross-Linking Networks

Mechanically Robust, Recyclable, and Highly Thermally Conductive Ethylene–Propylene–Diene Monomer/Boron Nitride Composite Enabled by Multiple Interfacial Cross-Linking Networks

Tailored Ni‐Zn‐Cu ferrite/EPDM nanocomposites: Synthesis, characterization, and multifaceted properties for mechanical and electrical applications

AbstractIn this study, we prepared Ni‐Zn‐Cu Fe2O4 ferrite/ethylene propylene diene monomer (EPDM) rubber nanocomposites with enhanced mechanical and electrical properties. First, Ni‐Zn‐Cu Fe2O4 ferrite nanoparticles were synthesized with a tailored composition of NiZn(0.3)Cu(0.2)Fe2O4(2). Subsequently, these nanoparticles were incorporated into the EPDM rubber matrix through a two‐roll mixing mill. Scanning electron microscopy and x‐rays diffraction techniques were used to explore their morphology and structure. Fourier‐transform infrared spectroscopy was used to identify metal‐oxygen bonds in the nanoparticles and their incorporation in the nanocomposites. Similarly, curing properties, including optimum cure time, scorch time, and torque profiles, were evaluated using a moving die rheometer. While, mechanical properties of these composites, such as tensile strength and Young's modulus, were determined with a universal testing machine. Tensile strength improved from 0.11 MPa to 0.22 MPa (100% increase), whereas, the Young's modulus increased from 0.03 MPa to 0.052 MPa (86% increase). Additionally, we investigated the dielectric properties of these nanocomposites, encompassing permittivity, resistivity, and dielectric constant, using a dielectric properties analyzer. Our findings revealed a significant reduction in dielectric resistivity of nanocomposites (from 33.2 GΩ to 23.38 GΩ) upon the introduction of Ni‐Zn‐Cu Fe2O4 ferrite nanoparticles, indicating the formation of a continuous nanofiller network within the EPDM matrix. Interestingly, as the nanofiller loading increased, both dielectric permittivity and dielectric constant exhibited a gradual rise. The permittivity value increased from 2.31 to 2.39 (Fm−1), while the dielectric constant increased from 0.0091 to 0.0179.Highlights Synthesized Ni‐Zn‐Cu Fe2O4; tuned composition NiZn(0.3)Cu(0.2)Fe2O4(2). Integrated ferrite into EPDM; optimized mixing for enhanced properties. Employed SEM, XRD, and FTIR; revealed morphology, structure, and bonding. Evaluated curing using MDR; unveiled optimal time and torque profiles. Explored dielectric properties; demonstrated reduced resistivity, heightened permittivity.

Effects of nanomagnesia and polypropylene-graft-maleic anhydride on the dielectric breakdown properties of polypropylene/ethylene propylene diene monomer blend

Thermoplastic polypropylene (PP) has garnered a significant attention in power cable insulation research because of its exceptional thermal tolerance and dielectric properties. Due to its poor impact strength at room temperature, PP has been blended with various elastomers, including ethylene-propylene-diene monomer (EPDM), to improve the mechanical stiffness of the final material. This, however, comes with compromised dielectric properties of the material. Recently, the addition of nanofillers to polymers has demonstrated promising properties that can be tailored for various dielectric applications, provided that nanofiller and polymer interactions are appropriately formulated. Nevertheless, the effect of nanostructuration in PP/elastomer blends, especially from the perspective of dielectrics, have yet to be systematically explored. In the current work, magnesia (MgO) nanofiller is added to a model PP/EPDM blend system to determine the effect of MgO on the breakdown properties of PP/EPDM. The results show that adding 0.5 wt% of MgO to PP/EPDM reduces the AC and DC breakdown strengths by 7% and 16%, respectively. As the amount of MgO increases to 3 wt%, the AC and DC breakdown strength reduces further by 25% and 29%, respectively. Significantly, appropriate modification of the nanocomposites with polypropylene-graft-maleic anhydride (PP-g-MAH) can result in 5% higher breakdown strength of the nanocomposites with respect to comparable nanocomposites without modification. The mechanisms surrounding these breakdown effects are discussed with the aid of materials structure interpretations. Overall, the results demonstrate that appropriate modification of nanocomposites with PP-g-MAH is crucial in tailoring breakdown properties of PP blend nanocomposites.

Microplastics in human blood: Polymer types, concentrations and characterisation using μFTIR

Microplastics (MPs) are an everyday part of life, and are now ubiquitous in the environment. Crucially, MPs have not just been found within the environment, but also within human bodies, including the blood. We aimed to provide novel information on the range of MP polymer types present, as well as their size and shape characteristics, in human whole blood from 20 healthy volunteers. Twenty-four polymer types were identified from 18 out of 20 (90 %) donors and quantified in blood, with the majority observed for the first time. Using an LOQ approach, five polymer types met the threshold with a lower mean ± SD of 2466 ± 4174 MP/L. The concentrations of plastics analysed in blood samples ranged from 1.84 − 4.65 μg/mL. Polyethylene (32 %), ethylene propylene diene (14 %), and ethylene–vinyl-acetate/alcohol (12 %) fragments were the most abundant. MP particles that were identified within the blood samples had a mean particle length of 127.99 ± 293.26 µm (7–3000 µm), and a mean particle width of 57.88 ± 88.89 µm (5–800 µm). The MPs were predominantly categorised as fragments (88 %) and were white/clear (79 %). A variety of plastic additive chemicals were identified including endocrine disrupting-classed phthalates. The procedural blank samples comprised 7 polymer types, that were distinct from those identified in blood, mainly resin (25 %), polyethylene terephthalate (17 %), and polystyrene (17 %) with a mean ± SD of 4.80 ± 5.59 MP/L. This study adds to the growing evidence that MPs are taken up into the human body and are transported via the bloodstream. The shape and sizes of the particles raise important questions with respect to their presence and associated hazards in terms of potential detrimental impacts such as vascular inflammation, build up within major organs, and changes to either immune cell response, or haemostasis and thrombosis.

Assessment of properties of bamboo fiber and EPDM reinforced polypropylene microcellular foam composites

Plant fiber reinforced composite has broad industrial application prospects, and has the trend of gradually replacing traditional materials, but there are also problems such as not obvious advantages of lightweight and poor toughness. In this paper, alkali modified bamboo fiber reinforced polypropylene (BF/PP) composite was prepared by supercritical foam injection molding. The effect of fiber content on the formability of BF/PP composite was studied. Furthermore, the strength and toughness of BF/PP composites were balanced by blending Ethylene Propylene Diene Monomer (EPDM) elastomers with different content under the optimal fiber content of 20 %. The physical and mechanical properties of BF/PP composites were studied. The results showed that the addition of bamboo fiber improved the structure of the cell and significantly enhanced the mechanical properties of the composite. The addition of elastomer EPDM effectively alleviates the problem of poor toughness and brittle fracture of bamboo fiber composites. The foam material density decreased by about 15 %, the addition of bamboo fiber brought the maximum 57.37 % tensile strength and 79.96 % flexural strength improvement to the polypropylene matrix. When the EPDM content was 10 %, the foaming effect of the material was the best, and the impact toughness increased by 34.42 % compared with pure polypropylene. This study expands the application prospect of the bamboo fiber reinforced polypropylene microcellular foam materials.

Importance of an interfacial agent for stabilizing rubber domains of thermoplastic vulcanizates during strong shearing

Rubber nanoparticles in thermoplastic vulcanizate (TPV) may agglomerate during processing, leading to the deterioration of mechanical properties of TPV. This work shows how important an interfacial agent (Polyolefin Elastomer, POE) can be for stabilizing rubber particles in Ethylene-Propylene-Diene Monomer (EPDM)/polypropylene (PP) TPV during processing. The optimal type and dosage of POE was theoretically calculated. The time at which the POE interfacial agent is added is optimized based on the fragmentation kinetics of the EPDM rubber particles. The experimental results show that POE is indeed encapsulated on EPDM rubber particles in TPV, resulting in the large decrease in average size of EPDM rubber particles from 1.2 μm for TPV without encapsulation to 0.7 μm for TPV encapsulated with optimal dosage of POE. As a result, at an optimal dosage of POE, the elastic modulus, tensile strength, and elongation at break of TPV simultaneously increases by 70 %, 44 %, and 37 %, respectively.

Synthesis of liquid EPDM having ultra-low-viscosity for curing at room temperature

A serial of liquid ethylene–propylene–diene rubber (EPDM) with 5-ethylidene-2-norbornene (ENB) contents of 2.0–6.5 mol% were synthesized by using VOCl3 based catalysts. The obtained polymers have much low molecular weight with Mn = 4530–10180 g/mol (PDI = 3.5–7.1), consequently, these EPDMs without solvent have excellent flowability with the viscosity of 2198∼7460 mPa s at 25 °C. And the glass transition temperature as low as −85.9 °C was achieved. Impressively, these liquid EPDMs can be cured at 25 °C after 5 days. NMR analysis suggested that ethyl trichloroacetate acted as activator to chlorinate V(II) species to V(III), but also acted as polymer modifier to provide a chlorinated EPDM, which appeared to be essential for liquid EPDMs curing at low temperature. The dynamic water contact angle results demonstrated that the EPDMs had excellent wettability properties and surface properties. Thus, this work provided a facile way for one-pot synthesis of liquid EPDM containing functional group for curing at room temperature.

Analysis of Carbon Black Proportion on Durability and Wear Behavior of EPDM Rubber

This study aims at understanding the effect of carbon black on mechanical properties of EPDM rubber. For this we select combination of carbon blacks N330 and N550 with standard curing procedure to minimize the wear rate and maximize durability. The EPDM rubbers were characterized using hardness, tensile, wear and durability tests. The coefficient of friction (COF), volume loss and wear rate of the EPDM rubbers were determined. It was found that with increasing CB content all above characteristics were reduced. Result shows that by using optimum combination of carbon black we can enhance wear performance and durability of EPDM rubber.

Developing a flame-retardant flexible composite phase change material to realize both temperature control and thermal runaway prevention for lithium-ion battery pack

Exploring a facile solution to controlling the operating temperature within the range between −25 °C and 60 °C and the temperature difference between batteries less than 5 °C as well as preventing thermal runaway for battery packs, is significant, but remains challenging. Herein, a flame-retardant flexible composite phase change material was developed and applied for both the temperature control and thermal runaway prevention of battery packs. Specifically, a flame-retardant coating comprising 70 % polydimethylsiloxane as a binder was first investigated to determine the optimal mass ratio of 3:1 for the blend of expandable graphite and ammonium polyphosphate. The flame-retardant flexible composite phase change material was then produced by applying the optimal coating at a loading of 15 % on a flexible composite phase change material that was obtained from incorporating an ethylene propylene diene monomer with a mass fraction of 40 % into an 80 % paraffin/20 % expanded graphite composite. The flame-retardant flexible CPCM not only exhibited the highest flame-retardant rating of V-0, a significant latent heat capacity and good thermal reliability, but also demonstrated improved thermal conductivity and enhanced mechanical properties in tensile strength, bending, and compression as compared with the uncoated counterpart. The flame-retardant flexible composite phase change material achieves better temperature control performance for a battery pack compared to the material without a flame-retardant coating. Moreover, the flame-retardant flexible composite phase change material effectively prevents thermal runaway propagation within a battery pack. These favorable characteristics demonstrate the considerable potential of the flame-retardant flexible CPCM for battery thermal management in electric vehicles.

Effect of Ethylene-Propylene-Diene Monomer Blending on the Dielectric Properties of Polypropylene for Power Cable Insulation

Thermoplastic materials such as polypropylene (PP) are ideal candidates to be used as power cable insulation materials. However, the mechanical properties of PP, which is brittle and stiff, need to be modified to meet the requirements of power cable insulation applications. To overcome this, ethylene-propylene-diene monomer (EPDM) can be melt blended with PP to improve PP’s mechanical properties. In the current work, the effect of blending different contents of EPDM with PP was investigated in terms of the morphology, chemical structure, dielectric response, electrical, and mechanical properties. The results show that the EPDM blended well with the PP as the EPDM dispersed in the PP structure. Meanwhile, the chemical structure and dielectric response of the EPDM and PP blend became slightly different with high contents of EPDM, which subsequently affected the breakdown strength and mechanical properties. Nevertheless, it is worth noting that PP blended with low contents of EPDM has the potential to be used as recyclable power cable insulation materials.

Thermal Oxidative Aging and Service Life Prediction of Commercial Ethylene-Propylene-Diene Monomer Spacer Damping Composites for High-Voltage Transmission Lines.

The aging behavior and life prediction of rubber composites are crucial for ensuring high-voltage transmission line safety. In this study, commercially available ethylene-propylene-diene monomer (EPDM) spacer composites were chosen and investigated to elucidate the structure and performance changes under various aging conditions. The results showed an increased C=O peak intensity with increasing aging time, suggesting intensified oxidation of ethylene and propylene units. Furthermore, the surface morphology of commercial EPDM composites displayed increased roughness and aggregation after aging. Furthermore, hardness, modulus at 100% elongation, and tensile strength of commercial EPDM composites exhibited a general increase, while elongation at break decreased. Additionally, the damping performance decreased significantly after aging, with a 20.6% reduction in loss factor (20 °C) after aging at 100 °C for 672 h. With increasing aging time and temperature, the compression set gradually rose due to the irreversible movement of the rubber chains under stress. A life prediction model was developed based on a compression set to estimate the lifetime of rubber composites for spacer bars. The results showed that the product's life was 8.4 years at 20 °C. Therefore, the establishment of a life prediction model for rubber composites can provide valuable technical support for spacer product services.

Investigation of the variation of mechanical and durability properties of elements manufactured with rubber substituted SCMs with element height

Controlling the homogeneous distribution of granulated rubber materials added to self-compacting concrete/mortars along the height is of great importance in terms of preserving and defining the holistic behavior of structural elements. In this study, the effect of EPDMGR (ethylene propylene diene monomer granulated rubber) ratio (0 %, 5 %, 10 %, 15 %, 20 % and 25 %), test age, L/D (slenderness ratio) and element test zone (bottom, middle and top) on the mechanical properties (flexural and compressive), durability properties (porosity and sorptivity) of the elements produced with SCM were evaluated. The results obtained were statistically evaluated by GLM-ANOVA. It was observed that flexural tensile strength was strengthened up to 5 % substitution rate due to the hydrophobic properties and elasticity properties of EPDMGR used, while porosity values increased with height in the upper regions compared to the lower regions due to the placement properties of SCM. Differences in compressive strength appeared in the upper and lower sections after 5 % EPDMGR substitution. This indicates that for the mixture properties used, the properties examined in terms of mechanical and durability test results may have different properties with limited variability in terms of L/D ratio depending on the EPDMGR ratio used and the region where the element was taken.

Multiscale simulation study on radiation aging of EPDM and preparation of radiation-resistant materials

With the wide application of ethylene propylene diene monomer (EPDM) in the field of nuclear engineering, exploring the radiation aging mechanism of EPDM is of great significance to improve the radiation resistance of EPDM composites. In this paper, the radiation aging mechanism of EPDM was investigated by a combination of experiments and multiscale simulations, and EPDM composites with excellent radiation resistance were prepared. The radiation aging mechanism of EPDM involves the crosslinking and degradation of molecular chains. The aging of EPDM starts from the breakage of α-H in the 5-ethylidene-2-norbornene monomer. In addition, the screening strategy of radiation-resistant additives was proposed. Antioxidants N, N′-diphenyl-p-phenylene-diamine (H), N, N′-ditolyl-p-phenylenediamine (DTPD), and N, N′-di-2-naphthyl-p-phenylenediamine (DNP) were taken as the main research objects, and quantitative analysis was carried out from the aspects of chemical protection and physical protection. The screening results showed that DNP has excellent radiation resistance and migration resistance. The prepared EPDM-DNP composites showed outstanding radiation resistance with 94% tensile strength retention after 300 kGy irradiation. This work contributes to understand the mechanisms of radiation-induced material damage and guides the design of radiation-resistant materials.

Formation/Removal of Biofilms on/from Coupons of Selected Food-Grade Elastomeric Polymers vs. Plexiglass Used for the Fruit-Catching Plates of OTR Blueberry Machine Harvesters

To reduce the bruising potential of machine-harvested fresh blueberries, manufacturers of over-the-row (OTR) machine harvesters are replacing the hard, plexiglass fruit-catching plates with soft, elastomeric polymers. This study assessed whether selected soft, food-grade elastomeric polymers, with the potential to be used in OTR harvesters, have a greater likelihood to encourage more microbial buildups, making cleaning/sanitation a greater challenge. Coupons of plexiglass, silicone, neoprene, and ethylene propylene diene monomer (EPDM) were exposed to fecal coliforms from various sources for biofilm development. The coupons with developed biofilms were treated with sodium hypochlorite, peracetic acid, isopropyl alcohol-based quaternary ammonium compounds (Alpet D2), or commercial dish soap. Biofilms and their residuals after the sanitizer treatments were quantified. The fecal coliforms isolated from the surface of OTR harvesters developed significantly (p ≤ 0.05) more biofilms than those from other sources. EPDM coupons had significantly more, while neoprene and silicone coupons had insignificantly different (p > 0.05) amounts of biofilms from plexiglass coupons. After sanitizer treatments, EPDM coupons had significantly more, while neoprene and certain silicon coupons had significantly fewer residues than plexiglass coupons. Study suggests that compared to plexiglass, neoprene and silicon did not support more microbial buildups or retain more biofilms after sanitizing treatments.

The Synergistic Effect of Carbon Black/Carbon Nanotube Hybrid Fillers on the Physical and Mechanical Properties of EPDM Composites after Exposure to High-Pressure Hydrogen Gas.

This study investigated the synergistic effect of carbon black/multi-wall carbon nanotube (CB/MWCNT) hybrid fillers on the physical and mechanical properties of Ethylene propylene diene rubber (EPDM) composites after exposure to high-pressure hydrogen gas. The EPDM/CB/CNT hybrid composites were prepared by using the EPDM/MWCNT master batch (MB) with 10 phr CNTs to enhance the dispersion of CNTs in hybrid composites. The investigation included a detailed analysis of cure characteristics, crosslink density, Payne effect, mechanical properties, and hydrogen permeation properties. After exposure to 96.3 MPa hydrogen gas, the hydrogen uptake and the change in volume and mechanical properties of the composites were assessed. We found that as the MWCNT volume fraction in fillers increased, the crosslink density, filler-filler interaction, and modulus of hybrid composites increased. The hydrogen uptake and the solubility of the composites decreased with an increasing MWCNT volume fraction in fillers. Moreover, after exposure to hydrogen gas, the change in volume and mechanical properties exhibited a diminishing trend with a higher MWCNT volume fraction. We conclude that the hybridization of CB and CNTs formed strong filler-filler networks in hybrid composites, consequently reinforcing the EPDM composites and enhancing the barrier properties of hydrogen gas.

Simultaneously achieving excellent heat aging resistance and grip performance in carbon black/glass flake/EPDM rubber composite for overhead line spacers

The preparation of wire clamp rubber with semiconductivity, low compression set (C-Set), high mechanical strength, heat aging resistance, and high grip strength is vital for overhead line spacers. This study delves into the formulation design of high-performance ethylene-propylene-diene monomer (EPDM) composite materials for wire clamp rubber. The effects of the vulcanization system, carbon black type, and loading on the essential material properties of EPDM rubber were investigated. The results showed that a hybrid vulcanization system containing peroxide and sulfur simultaneously endowed EPDM rubber with high elasticity and tear strength. N330 carbon black-filled EPDM rubber had the advantages of semiconductivity and high tensile strength, and N774 carbon black-filled EPDM rubber exhibited low C-Set and high heat aging resistance. When EPDM rubber was reinforced with the mixture of 50 phr N330 and 20 phr N774 carbon black, the rubber synchronously exhibited semiconductivity (2.64×106 Ω·cm), high tensile strength (20.2 MPa), low C-Set (32.5%, 150°C×3d), and high heat aging resistance (maintaining 98% of its initial tensile strength after aging at 150°C for 3d). In addition, introducing a 10-phr glass flake into EPDM wire clamp rubber improved the grip force by 83%. The improvement mechanism may be attributed to the increased compression stress of wire clamp rubber on cable and the restricted slippage of rubber molecular chains.

Elasto-Plastic Materials based on EPDM Rubber, LDPE, Plasticized Starch and OMMT

This paper describes the development of new types of dynamically cross-linked thermoplastic elastomers based on ethylene-propylene-terpolymer rubber and low-density polyethylene, reinforced with plasticized starch and montmorillonite with a chemically modified surface. An octylphenol-formaldehyde resin in the presence of stannous chloride dihydrate was used as a vulcanizing agent. The samples were obtained on a Brabender Plasti-Corder mixer, at appropriate temperatures and rotation speeds, using the dynamic vulcanization method and the melt intercalation technique. The mixtures obtained were modeled in the form of plates with standard dimensions using specific molds and a laboratory-scale electrical press. The obtained samples were analyzed from the point of view of the physical-mechanical properties, the melt flow index, as well as from the structural and morphological point of view. It was observed that the characteristics of the samples are influenced by both the composition and the methods of obtaining used. According to the obtained characteristics, the new elasto-plastic materials can be used in fields such as the footwear industry (for the production of: soles, heels, protective boots), in the rubber and plastics industry, the automobile industry, agriculture or construction (when making gaskets, technical items, hoses, etc.). They can be easily processed into different finished products by methods specific to plastics.