Effect of thermo-oxidation on the dynamical and physical properties of ethylene-propylene-diene monomer elastomer

Wang, Ya-jian; Yang, Yiqin; Wang, Linbing

doi:10.1631/jzus.a2000312

Cited by 3 publications

(5 citation statements)

References 43 publications

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“…The products of thermal oxidation of EPDM are mainly ketones, carboxylic acids, hydroxyl alcohols, and ethers [ 2 , 25 ]. Of these, ethers are observed to be the main type of regenerative cross-link produced after thermal-oxidative ageing.…”

Section: Cross-linking Types Of Epdmmentioning

confidence: 99%

“…Wang et al constructed an EPDM cross-linking algorithm, whereby a cross-linked EPDM was established in the MD simulation process, and then they further investigated the free volume properties with the EPDM and the applicability of the principles of the time–temperature superposition principle (TTSP) and time–stress superposition principle (TSSP) [ 20 ]. Wang et al used MD simulations to study the impact of thermal oxidation on an EPDM’s dynamic and mechanical characteristics [ 25 ], while previous investigations have confirmed the validity and the reliability of MD simulations for evaluating EPDM properties.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Cross-Linking Type on EPDM Elastomer Dynamics and Mechanical Properties: A Molecular Dynamics Simulation Study

Wang

Liu

et al. 2022

Polymers

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The cross-linking structure of the Ethylene-propylene-diene monomer (EPDM) is made up of a number of cross-linking types, including carbon atoms from the main chain or monomer and ether crosslinks formed during degradation. Through molecular dynamic simulations, the contribution of each type of cross-linked structure to the dynamics and mechanical properties of EPDM, the study’s focus, were investigated. Cross-linking between the tertiary carbons of two main chains, cross-linking at the monomer’s unsaturated position, ether cross-linking after oxidation, and other combinations of target cross-linked carbon atoms from different positions, totaling eight types of cross-linked types, were mixed with EPDM free chains in a 1:1 ratio to form eight types of cross-linked EPDMs. These varieties of cross-linked EPDMs were then compared to an uncross-linked EPDM in terms of density, radius of gyration, free volume, mean square displacement, and uniaxial tensile stress-strain curves. It was found that the cross-linking was always proven to have a favorable influence on mechanical characteristics; however, the relaxation inhibition effect varied. The cross-linking between the diene monomer at the C9 position resulted in a more flexible molecular shape and was more than double the free volume of the uncross-linked EPDM, resulting in an improved diffusion ability. The ether cross-linking produced by the oxidation of the side chain cross-linking improved the positive contribution to stiffness and enhanced the inhibitory impact on diffusion properties, whereas the main chain cross-linking had the opposite effect. The research presented in this study leads to a better knowledge of the microscopic aspects underlying EPDM performance.

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Section: Cross-linking Types Of Epdmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Cross-Linking Type on EPDM Elastomer Dynamics and Mechanical Properties: A Molecular Dynamics Simulation Study

Wang

Liu

et al. 2022

Polymers

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“…RS refers to red, dark red, or brown sedimentary rocks such as mudstones, murky sandstones, granular mudstones, and siltstones. They have low hardness and are easily dissolved in water to create sandstone soils because they are rich in hydrophilic clay minerals and iron oxides [ 1 , 2 , 3 , 4 ]. The principal chemical constituents are SiO 2 , Al 2 O 3 , CaO, and Fe 2 O 3 , and the SiO 2 and Al 2 O 3 content of which generally exceeds 80% [ 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

Kong,

Zhou,

Guo

et al. 2023

Materials

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Based on the physical and chemical properties of red sandstone (RS), RS is used to produce composite cementitious materials. The flowability, mechanical strength, and micromechanics of a red sandstone–cement binary cementitious material (RS-OPC) were investigated as functions of the amount of RS replacing the cement (OPC). Additionally, the feasibility of producing red sandstone–phosphogypsum–cement composite materials (RS-PG-OPC) using the phosphogypsum (PG)- enhanced volcanic ash activity of RS was investigated. The products of hydration and microstructures of RS-OPC and RS-PG-OPC were analyzed by XRD, FTIR, TG-DTG, and SEM. RS enhanced the flowability of RS-OPC relative to the unmodified cement slurry but lowered its mechanical strength, according to the experiments. When the quantity of OPC replaced was greater than 25%, the compressive strength after 28 days was substantially reduced, with a maximum reduction of 78.8% (RS-60). The microscopic mechanism of RS-OPC suggested that the active SiO2 in the RS can react with Ca(OH)2 to produce C-S-H but can only utilize small quantities of Ca(OH)2, confirming the low volcanic ash activity of RS. RS was responsible for dilution and filling. The incorporation of 5% PG into RS-PG-OPC slowed the hydration process compared with RS-OPC without PG but also increased the flowability and aided in the later development of the mechanical strength. This was primarily because the addition of PG provided the system with sufficient Ca2+ and SO42− to react with [Al(OH)6]3− to form ettringite (AFt), therefore accelerating the dissolution of Al3+ in RS to generate more AFt and C-(A)-S-H gels. To some extent, this excites the volcanic ash of RS. Therefore, if there is an abundance of waste RS in the region and a lack of other auxiliary cementitious materials, a sufficient quantity of PG and a finely powdered waste RS component can be used to replace cementitious materials prepared with OPC to reduce the mining of raw OPC materials.

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“…The speed of thermal oxygen aging varies at different temperatures, and as time progresses, EPDM vulcanized rubber changes from initial chain degradation reaction to continued cross-linking, and the degree of cross-linking increases. [28][29][30] In this work, nylon-based thermoplastic elastomers and EPDM were selected and used to prepare vulcanized rubber samples. The crosslink density was calculated by equilibrium swelling method, and the relationship between total crosslink density and chemical and physical crosslink was systematically analyzed.…”

Section: Introductionmentioning

confidence: 99%

“…The chain initiation and chain growth stages occur in chain breakage and combine with oxygen to form peroxy radicals, and the chain termination occurs in the cross‐linking reaction, so that the product undergoes further cross‐linking. The speed of thermal oxygen aging varies at different temperatures, and as time progresses, EPDM vulcanized rubber changes from initial chain degradation reaction to continued cross‐linking, and the degree of cross‐linking increases 28–30 …”

Section: Introductionmentioning

confidence: 99%

The novelty role of polyamide elastomer in the determination of crosslink density and the formation of crosslink network of EPDM vulcanizates

Hao

Kadlčák²,

Xu³

et al. 2023

Polymers for Advanced Techs

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The effect of polyamide elastomer (PAE) on the crosslink network of ethylene propylene diene monomer (EPDM) was systematically investigated by using equilibrium swelling method and rheological experiment. The swelling systems of the EPDM‐PAE vulcanizates were discussed by classification way. The results showed that PAE was involved in the construction of the crosslink network and decreases the chemical crosslink density and the total crosslink degree of EPDM vulcanizate. By linearly fitting the relationship between chemical crosslink density and total crosslink degree, the physical crosslink degrees of EPDM, EPDM‐PAE and PAE were estimated as 9.135, 2.934, and 0.820 dNm, respectively. The physical crosslink degree of EPDM vulcanizates was mainly contributed by the entanglement of rubber macromolecular chains. By contrast, the interaction of the inter‐macromolecular chains of EPDM‐PAE and the physical crosslink of PAE itself contributed less to the physical crosslink degree of EPDM vulcanizates. With the increase of aging time under 150°C, the roles of PAE in continuously promoting the crosslink reaction and leading to the degradation of crosslink network resulted in various changes in crosslink density and mechanical properties. It could be expected from this study that the construction of the crosslink network of EPDM‐PAE composite was unique, which provided a novel perspective on the microscopic crosslink structures and macroscopic properties of EPDM‐PAE based products.

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Effect of thermo-oxidation on the dynamical and physical properties of ethylene-propylene-diene monomer elastomer

Cited by 3 publications

References 43 publications

The Effect of Cross-Linking Type on EPDM Elastomer Dynamics and Mechanical Properties: A Molecular Dynamics Simulation Study

The Effect of Cross-Linking Type on EPDM Elastomer Dynamics and Mechanical Properties: A Molecular Dynamics Simulation Study

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

The novelty role of polyamide elastomer in the determination of crosslink density and the formation of crosslink network of EPDM vulcanizates

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