Atomistic investigation of fracture mechanisms in phosphorus-functionalized epoxy resins

Xu, Hao; Gao, Chang; Meng, Zhaoxu; Wang, Ao; Keten, Sinan; Wu, Zhanjun

doi:10.1016/j.ijmecsci.2022.107412

Cited by 4 publications

(5 citation statements)

References 54 publications

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“…Glassy polymers show nanoscale void and fibril formation similar to what we observe in epoxies. Moreover, previous studies have used this analogy for accurately predicting fracture energy − in neat epoxies, phosphorus-functionalized epoxies, epoxy–graphene interfaces, and glass-forming polymers. According to this model, G c = 2 π d σ italicm italica italicx 2 σ p ( 1 − 1 λ ) C 11 C 66 .…”

Section: Results and Discussionmentioning

confidence: 99%

“…Rottler et al employed the same analogy to craze formation in a glassy polymer under a plane stress condition at different stages of deformation. Recent studies have used both techniques for accurately predicting fracture energy − in neat epoxies, phosphorus-functionalized epoxies, epoxy–graphene interfaces, and glass-forming polymers. However, previous MD studies mainly focus on binary epoxy with single resin and hardener mixer.…”

Section: Introductionmentioning

confidence: 99%

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Predicting the Effect of Hardener Composition on the Mechanical and Fracture Properties of Epoxy Resins Using Molecular Modeling

et al. 2023

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Improving the toughness of brittle epoxy while keeping its high strength-to-weight ratio is challenging, as these two properties work against each other. Fracture processes are difficult to ascertain with experiments, as they occur at nanoscopic lengths and time scales and require higher efficiency than what can be attained with atomistic simulations. To overcome this challenge, we utilize a recently developed chemistry specific coarse-grained model to examine two different hardeners, diamine 4,4′-methylenebis(cyclohexylamine) (PACM) and propylene oxide diamine (Jeffamine), to cure bisphenol A diglycidyl ether (DGEBA) at varying stoichiometries and understand how hardener composition influences the elasticity, yield strength, and fracture toughness of epoxy resins. The results indicate that PACM mainly contributes to the modulus and that long Jeffamine chains increase fracture toughness by making the epoxy ductile, whereas short Jeffamine chains significantly improve the yield strength. Longer Jeffamines also lead to larger voids and the formation of fibrils that carry a significant amount of stress and contribute to toughness. Interestingly, the Ashby plots reveal that epoxies with intermediate-length Jeffamine chains (D800 and D2000) outperform other systems, as the toughness enhancement from flexible Jeffamine chains and the stiffness due to PACM help to overcome the strength−toughness trade-off. Our modeling framework and findings establish a path toward resin design from predictive multiscale models with no empirical input and reveal new insights into the molecular failure mechanisms of epoxy resins.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Predicting the Effect of Hardener Composition on the Mechanical and Fracture Properties of Epoxy Resins Using Molecular Modeling

et al. 2023

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“…A variety of thermo-mechanical properties of epoxy thermosets, − including glass-transition temperature ( T g ), Young’s modulus, coefficient of thermal expansion (CTE), were predicted using AA models. By considering the effects of strain rate and temperature, the simulated results show satisfactory consistency with experimental data. − In, microscopic fracture mechanism in highly cross-linked epoxy thermosets were investigated, where behaviors including bond scission event, chain elongation and void evolution were studied. While with high accuracies, AA simulation was restricted in spatial and time scales due to limited computing capacity.…”

Section: Introductionmentioning

confidence: 99%

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

Gao,

Chen,

Dong

et al. 2024

J. Phys. Chem. B

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Coarse-grained modeling shows potential in exploring the thermo-mechanical behaviors of polymers applied in harsh conditions such as cryogenic environment, but its accuracy in simulating fracture behaviors of highly cross-linked epoxy thermosets is largely limited due to the complex molecular structures of the cross-linked networks. We address this fundamental problem by developing a CG modeling method where the backbones and electrostatic interaction (EI) contributions in the cross-linked networks are retained, and thus the potentials of the CG model can be directly extracted, or parametrized on the basis of, existing all-atomistic (AA) force fields. A multilevel parametrization procedure was adopted, where the bond potentials were parametrized relying on the results of density functional theory (DFT) simulation, whereas the nonbond potentials were parametrized by renormalizing the cohesive interaction strength. Remarkably, the CG model can reproduce stress−strain responses highly consistent with the AA simulation results at multiple stages, including elastic deformation, yielding, plastic flow, strain hardening, etc., and the straightforward parametrization procedure can be easily transferred to different materials and thermodynamic conditions. The CG modeling method was then used to build a large-scale representative volume element (RVE) to investigate the microscopic fracture behavior of an epoxy thermoset. It has been discovered that EI contributions play a significant role in generating correct mechanical responses and fracture morphologies. The influences of temperature (i.e., from room to cryogenic temperatures) and strain rates were discussed, and the fracture morphology in the RVE was unveiled and analyzed in a quantitative manner.

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“…16,17 Reports on resin matrix composite liquid oxygen storage tanks mainly focused on epoxy resin (EP) and cyanate ester resin (CE). [18][19][20] Liquid oxygen was highly oxidizing at low temperatures, so resin matrix composite tanks must prioritize safety, that is, resin toughness and oxidation resistance at low temperatures. The EP resin contained numerous hydroxyl groups, ether bonds, and other easily oxidizable groups, resulting in poor flame retardancy and oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

“…Reports on resin matrix composite liquid oxygen storage tanks mainly focused on epoxy resin (EP) and cyanate ester resin (CE) 18–20 . Liquid oxygen was highly oxidizing at low temperatures, so resin matrix composite tanks must prioritize safety, that is, resin toughness and oxidation resistance at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Study on liquid oxygen compatibility of poly(phthalazinone ether) resins and their composites

Wang,

Li,

et al. 2024

Polymer Composites

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Nine poly(phthalazinone ether ketone) resins were designed and synthesized using three bisphenol and four halogenated monomers. Poly(phthalazinone bisphenol ether ketone) (PPBEK) and poly(phthalazinone ether sulfone ketone) (PPBESK) demonstrated liquid oxygen compatibility (LOC), with PPBEK maintaining its LOC even after 20 days of immersion in liquid oxygen. The liquid oxygen compatibility mechanism of the polymers in the presence of force‐thermal‐chemical multi‐energy fields was analyzed using techniques such as thermal analysis‐infrared‐gas chromatography (TGA‐IR‐GC), thermogravimetric analysis (TGA), and x‐ray photoelectron spectroscopy (XPS). Carbon fiber (CF) reinforced composites were fabricated using PPBEK and PPBESK as matrices, with CF‐PPBEK composites successfully achieving LOC. The microcracking resistance and mechanical properties of the composites were investigated in liquid oxygen at 90 K. The interaction mechanism between the composites and liquid oxygen was elucidated, providing theoretical guidance and an experimental foundation for the application of resin matrix composites in liquid oxygen storage tanks.Highlights Poly(phthalazinone ether) resins were meticulously designed and synthesized. ·PPBEK and PPBESK exhibited excellent liquid oxygen compatibility. Composites exhibited excellent liquid oxygen compatibility. Composites exhibited excellent low‐temperature performance and heat resistance.

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Atomistic investigation of fracture mechanisms in phosphorus-functionalized epoxy resins

Cited by 4 publications

References 54 publications

Predicting the Effect of Hardener Composition on the Mechanical and Fracture Properties of Epoxy Resins Using Molecular Modeling

Predicting the Effect of Hardener Composition on the Mechanical and Fracture Properties of Epoxy Resins Using Molecular Modeling

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

Study on liquid oxygen compatibility of poly(phthalazinone ether) resins and their composites

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