A modus operandi toward interfacial enhancement of ethylene propylene diene monomer rubber/ polybenzoxazine blends using <scp>EPDM‐</scp>grafted<scp>‐</scp>vinyltrimethoxysilane copolymer

The low tensile strength of ethylene/α-octene co-polymer (POE) limits its application as high-strength materials. In this study, 3-amino-1,2,4-triazole (ATA) was grafted onto maleic anhydride functionalized POE (PM) by melt reaction to obtain side chains capable of forming hydrogen bonding and metal coordination bonding, and then ferric chloride hexahydrate and POE are blended with them to obtain composite materials with high strength and fracture energy. The introduction of iron-based coordination bonding and hydrogen bonding double dynamic crosslinking network endow thermoplastic elastomers with excellent mechanical strength and high toughness. Fourier transform infrared spectroscopy, rheological tests, and X-ray photoelectron spectroscopy reveal the existence of non-covalent crosslinking networks. Based on the strengthening and toughening of non-covalent dynamic crosslinking network, the tensile strength of the modified POE elastomer composites achieves 12.5 MPa along with the elongation at break of 3540%. In addition, the modified POE elastomer composites exhibit improved melt elasticity and thermal stability.

Section: Resultsmentioning

confidence: 99%

Modified ethylene/α‐octene co‐polymer elastomer composites with sacrificial bonds crosslinking networks and their reinforced mechanical performance

Liu

Lin

Huang

et al. 2023

“…This is also the reason for the high value of grafting efficiency. [24] The molecular weight of grafted polymer chains depends on the conditions of copolymer synthesis and is determined by the kinetics and parameters of grafting. [7] The molecular weight of the grafted PAA chains was determined from the degree of conversion, the concentration of AA and PP, and the efficiency of grafting (Table 1).…”

Section: Grafting Parametersmentioning

confidence: 99%

“…[23] On the other hand, graft copolymerization has a positive effect on the interfacial surface and improves compatibility in polymer systems. [24,25] In most cases, the values of the kinetic parameters of graft copolymerization differ from those of the radical polymerization of monomers. In the case of graft copolymerization of sodium styrenesulfonate on polyvinylidene fluoride films irradiated with an electron beam, the order of the reaction with respect to the concentration of the monomer and initiator turned out to be 2.84 and 1.20, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Molecular characteristics, mechanism of synthesis, adhesive properties of graft copolymer of chloroprene rubber with acrylic acid

Rafikov

Khodjaeva

Karimov

et al. 2022

Synthesized graft copolymers of chloroprene rubber with acrylic acid in a solution of a mixture of dimethylformamide and benzene, in the presence of potassium persulfate. The gravimetric method determined the orders of the reaction rate by the concentrations of acrylic acid (2.0) and potassium persulfate (1.2), the total activation energy of the process (24.4 kJ/mol). It was found that the degree of grafting increases up to 140% with an increase in the concentration of the monomer, initiator, temperature, and process time. The efficiency of grafting changes insignificantly with changes in synthesis conditions and has a high value (67%–91%) over a wide range of concentrations, temperatures, and times. With an increase in the concentration of acrylic acid and a process time of up to 8 h, the molecular weight of the grafted polyacrylic acid chains increases to 38,000. IR Fourier, 1H, and 13C NMR spectroscopic studies established the mechanism of graft copolymerization. Radical active centers are formed as a result of hydrogen abstraction from the rubber molecule after interaction with potassium persulfate. Copolymers synthesized at a mass ratio of rubber:acrylic acid from 1:0.5 to 1:2, have excellent adhesion to the surface of the skin and textile material.

“…[ 1–6 ] Ethylene Propylene Diene Monomer (EPDM), a terpolymer of ethylene, propylene, and non‐conjugated diene with excellent properties, such as low density, oil resistance, ablation resistance, and heat and oxygen aging, can be used in the preparation of sealing rings, hoses, thermal insulation layers, and military products. [ 7–12 ]…”

Section: Introductionmentioning

confidence: 99%

Study on supercritical CO₂‐assisted modification of aramid pulp and properties of its reinforced EPDM composites

Kong

Qin³

et al. 2022

Aramid pulp (AP) is often used as a composite reinforcement due to its excellent properties, but poor dispersion and interfacial adhesion restrict its application in composite materials. In this work, tetraethyl orthosilicate (TEOS) was carried on the surface of AP by supercritical CO2 (scCO2) and hydrolyzed to synthesize the nano‐silica, which improves the dispersion of AP in ethylene‐propylene‐diene elastomer (EPDM). The nano‐silica particles were deposited on the AP surface, and th modified AP was evenly dispersed in the EPDM composites based on the SEM results. Moreover, a silane coupling agent (KH‐560) was brought by scCO2 to further modify the nano‐silica on the surface of the AP to improve the interfacial adhesion. Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy results show that after KH‐560 modification, active epoxy groups were introduced on the surface of AP. The tensile strength and tear strength of the KH‐560‐nano‐silica‐AP/EPDM composites were significantly improved, reaching 8.98 and 42.06 MPa, which increased by 26% and 88.10%, respectively, compared with untreated‐AP/EPDM composites. Dynamic mechanical analysis shows that the storage modulus of KH‐560‐nano‐silica‐AP/EPDM composites increased to 2456 MPa compared with the pure EPDM for 1873 MPa, and the loss factor decreased. When the AP was modified in scCO2 with nano‐silica and KH‐560, the composites' oil resistance was also improved.