Molecular dynamics simulations on adhesion of epoxy-silica interface in salt environment

Yaphary, Yohannes L.; Yu, Zechuan; Lam, Raymond H. W.; Hui, David; Lau, Denvid

doi:10.1016/j.compositesb.2017.07.038

Cited by 97 publications

(31 citation statements)

References 45 publications

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“…The pulling force is normal to the wall and the spring constant k is chosen to be 200.0 kcal mol −1 Å −2 , which is used in previous interfacial adhesion studies of the polymer-bonded systems [15,29]. The pulling rate v is varied over two orders of magnitude, ranging from 2.5 to 50.0 m s −1 , which is in the slow deformation regime, as demonstrated in our recent study on the epoxysilica interface [13]. Actually, the slow deformation regime allows the adequate dynamic evolution of the system under the applied SMD pulling force, such as the continuous breakage and reformation of the non-bonded interactions.…”

Section: Equilibration and Smd Simulationmentioning

confidence: 99%

“…Extensive efforts have been focused on quantitatively describing the molecular origins of the interfacial deterioration of the epoxy-bonded systems [10][11][12][13]. The epoxybonded systems feature the hierarchical structures ranging from the epoxy molecule, the epoxy monomer, the cross-linked structure, to the mesoscale network with structural voids, and to the macroscale epoxy thin film bonded to the supporting substrate, as shown in figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Moisture effect on interfacial integrity of epoxy-bonded system: a hierarchical approach

Tam¹,

Chow²,

Lau³

2017

Nanotechnology

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The epoxy-bonded system has been widely used in various applications across different scale lengths. Prior investigations have indicated that the moisture-affected interfacial debonding is the major failure mode of such a system, but the fundamental mechanism remains unknown, such as the basis for the invasion of water molecules in the cross-linked epoxy and the epoxy-bonded interface. This prevents us from predicting the long-term performance of the epoxy-related applications under the effect of the moisture. Here, we use full atomistic models to investigate the response of the epoxy-bonded system towards the adhesion test, and provide a detailed analysis of the interfacial integrity under the moisture effect and the associated debonding mechanism. Molecular dynamics simulations show that water molecules affect the hierarchical structure of the epoxy-bonded system at the nanoscale by disrupting the film-substrate interaction and the molecular interaction within the epoxy, which leads to the detachment of the epoxy thin film, and the final interfacial debonding. The simulation results show good agreement with the experimental results of the epoxy-bonded system. Through identifying the relationship between the epoxy structure and the debonding mechanism at multiple scales, it is shown that the hierarchical structure of the epoxy-bonded system is crucial for the interfacial integrity. In particular, the available space of the epoxy-bonded system, which consists of various sizes ranging from the atomistic scale to the macroscale and is close to the interface facilitates the moisture accumulation, leading to a distinct interfacial debonding when compared to the dry scenario.

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Section: Equilibration and Smd Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Moisture effect on interfacial integrity of epoxy-bonded system: a hierarchical approach

Tam¹,

Chow²,

Lau³

2017

Nanotechnology

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“…In applying tensile or shear strain in bulk material in MD simulation, the stress-displacement curve can be directly calculated from simulation results, and this relationship describes the relationship of interfacial traction force and interfacial bonding opening displacement during delamination of the bilayer system, which is exactly the cohesive constitutive relation of the interface. Apart from quantifying the traction-separation relation for modeling the interface from empirical approaches, the interface property converted from MD simulation provides the scientific support in explaining the interaction between two materials at the interfacial region from the physics and/or chemistry point of view, which is a more efficient and fundamental approach to evaluate the structural behavior under moisture or other environmental attack [15,21,[119][120][121].…”

Section: Macroscale Model Using Finite Element Methodsmentioning

confidence: 99%

“…To further understand the interfacial debonding mechanism under the presence of moisture, a more fundamental approach which can capture the molecular interaction and the change of interfacial property at small scales is needed. Recently, atomistic modeling approach employing molecular dynamics (MD) simulation is studied to address the above issues [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Moisture Effect on the Material Interface Using Multiscale Modeling

Qin

Lau

2019

Multiscale Sci. Eng.

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Layered material systems are widely seen in various engineering applications such as thin films circuit boards in electronic engineering, lipid bilayer in biological engineering, and adhesive bonding in aerospace and civil engineering applications. However, the durability of the material interface can be seriously affected due to the prolonged exposure to water. Although the experimental studies have shown the reduction in terms of ultimate bond strength and fracture toughness for material interface, the shift in failure mode found in experiment cannot be explained using conventional fracture theory, which is related to the interaction between the water and material interface. To understand the debonding mechanism from a fundamental and comprehensive aspect and bridge knowledge from the atomistic scale to continuum scale, multiscale modeling approach has been proposed to study the debonding behavior of material interface under moisture effect. A number of studies have been conducted using multiscale modeling approach to investigate the debonding of material interface, and it is necessary to summarize these studies to understand the role of water molecules in weakening and diffusing at the material interface using different atomistic models, force fields and upscaling techniques. This paper provides a comprehensive review on the multiscale modeling of interfacial and delamination behavior of layered material system under moisture attack with the focus on the molecular dynamics simulation and finite element modeling. The FRP bonded concrete system is used as a representative to demonstrate the approach of multiscale modeling. The future research direction is recommended, which involves the consideration of roughness of substrate and structural voids at interface for the better understanding of durability issue for interface in layered material system under different environmental conditions.

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“…In addition, these properties can be easily modulated by the combination of epoxy resins and curing agents, as well as the curing conditions. Owing to these versatile properties, epoxy resins are mainly used as adhesives, coatings, and structural composites, as well as aerospace and electronic materials . To date, most commercialized epoxy resins and curing agents were prepared from petroleum resources.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of a new phosphorus‐containing furan‐based epoxy curing agent as a flame retardant

Toan

Park

Kim³

et al. 2019

Fire and Materials

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Summary In this study, 5‐hydroxymethyl‐2‐furfural (HMF) was used as a renewable resource for preparing an epoxy curing agent (furan‐based flame retardant, FBF), and a phosphorus‐containing functional group was also incorporated to enhance the flame retardancy of FBF. FBF was easily synthesized, and the total yield was 83%. 2‐Methyl imidazole was chosen as an accelerant to reduce the activation energy for the reaction of FBF with diglycidyl ether of bisphenol A (DGEBA). The DGEBA cured with FBF showed a low glass transition temperature and cross‐linking density compared with those of DGEBA cured with isophorondiamine (IPDA) and 4,4′‐diaminodiphenylmethane (DDM). However, the FBF‐cured DGEBA exhibited a comparable tensile strength with that of the DGEBA‐IPDA and DGEBA‐DDM systems (81.96 MPa) and a significantly higher tensile modulus (1721 MPa) owing to the H‐bonding via oxygens of the phosphorus group of FBF in the network structure. The DGEBA cured with FBF showed a high char yield and a high limitation of oxygen index value (29.7%) compared with those of the IPDA‐ and DDM‐cured ones. The cone calorimeter measurement also showed that the DGEBA‐FBF system had a low heat release rate, total heat release, and smoke production rate, indicating the improved flame retardancy mediated by FBF.

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Molecular dynamics simulations on adhesion of epoxy-silica interface in salt environment

Cited by 97 publications

References 45 publications

Moisture effect on interfacial integrity of epoxy-bonded system: a hierarchical approach

Moisture effect on interfacial integrity of epoxy-bonded system: a hierarchical approach

Evaluation of the Moisture Effect on the Material Interface Using Multiscale Modeling

Synthesis and characterization of a new phosphorus‐containing furan‐based epoxy curing agent as a flame retardant

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