scholarly journals Interfacial Binding Energy between Calcium-Silicate-Hydrates and Epoxy Resin: A Molecular Dynamics Study

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1683
Author(s):  
Xianfeng Wang ◽  
Wei Xie ◽  
Jun Ren ◽  
Jihua Zhu ◽  
Long-Yuan Li ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Binding Energy ◽  
Epoxy Resin ◽  
Chain Length ◽  
Dynamics Simulation ◽  
Cement Matrix ◽  
Curing Agent ◽  
Self Healing ◽  
Calcium Silicate Hydrates ◽  
Epoxy Curing

Microcapsules encapsulated within epoxy as a curing agent have been successfully applied in self-healing materials, in which the healing performance significantly depends on the binding behaviour of the epoxy curing agent with the cement matrix. In this paper, the binding energy was investigated by molecular dynamics simulation, which could overcome the shortcomings of traditional microscopic experimental methods. In addition to the construction of different molecular models of epoxy, curing agents, and dilutants, seven models were established to investigate the effects of chain length, curing agent, and epoxy resin chain direction on the interfacial binding energy. The results showed that an increase of chain length exhibited had limited effect on the binding energy, while the curing agent and the direction of the epoxy significantly affected the interfacial binding energy. Among different factors, the curing agent tetrethylenepentamine exhibited the highest value of interfacial binding energy by an increment of 31.03 kcal/mol, indicating a better binding ability of the microcapsule core and the cement matrix. This study provides a microscopic insight into the interface behaviour between the microcapsule core and the cement matrix.

scholarly journals Molecular Dynamics Study on Mechanical Properties of Interface between Urea-Formaldehyde Resin and Calcium-Silicate-Hydrates

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4054
Author(s):  
Xianfeng Wang ◽  
Wei Xie ◽  
Taoran Li ◽  
Jun Ren ◽  
Jihua Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Calcium Silicate ◽  
Urea Formaldehyde ◽  
Dynamics Simulation ◽  
Cement Matrix ◽  
Formaldehyde Resin ◽  
Self Healing ◽  
Binding Behavior ◽  
Composite Models

Microcapsule based self-healing concrete can automatically repair damage and improve the durability of concrete structures, the performance of which depends on the binding behavior between the microcapsule wall and cement matrix. However, conventional experimental methods could not provide detailed information on a microscopic level. In this paper, through molecular dynamics simulation, three composite models of Tobermorite (Tobermorite 9 Å, Tobermorite 11 Å, Tobermorite 14 Å), a mineral similar to Calcium-Silicate–Hydrate (C–S–H) gel, with the linear urea–formaldehyde (UF), the shell of the microcapsule, were established to investigate the mechanical properties and interface binding behaviour of the Tobermorite/UF composite. The results showed that the Young’s modulus, shear modulus and bulk modulus of Tobermorite/UF were lower than that of ‘pure’ Tobermorite, whereas the tensile strength and failure strain of Tobermorite/UF were higher than that of ‘pure’ Tobermorite. Moreover, through radial distribution function (RDF) analysis, the connection between Tobermorite and UF found a strong interaction between Ca, N, and O, whereas Si from Tobermorite and N from UF did not contribute to the interface binding strength. Finally, high binding energy between the Tobermorite and UF was observed. The research results should provide insights into the interface behavior between the microcapsule wall and the cement matrix.

STUDY OF AFFINITIES BETWEEN SINGLE-WALLED NANOTUBE AND EPOXY RESIN USING MOLECULAR DYNAMICS SIMULATION

2006 ◽  
Vol 05 (01) ◽  
pp. 131-144 ◽  
Author(s):  
JIHUA GOU ◽  
BIN FAN ◽  
GANGBING SONG ◽  
AURANGZEB KHAN
Keyword(s):  
Molecular Dynamics ◽  
Epoxy Resin ◽  
Md Simulation ◽  
Average Distance ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Repulsive Interaction ◽  
Curing Agent ◽  
Single Walled Nanotubes ◽  
Simulation Results

In the processing of carbon nanotube/polymer composites, the interactions between the nanotube and polymer matrix will occur at the molecular level. Understanding their interactions before curing is crucial for nanocomposites processing. In this study, molecular dynamics (MD) simulations were employed to reveal molecular interactions between (10, 10) single-walled nanotube and two kinds of epoxy resin systems. The two kinds of resin systems were EPON 862/EPI-CURE W curing agent (DETDA) and DGEBA (diglycidylether of bisphenol A)diethylenetriamine (DETA) curing agent. The MD simulation results show that the EPON 862, DETDA and DGEBA molecules had strong attractive interactions with single-walled nanotubes and their molecules changed their conformation to align their aromatic rings parallel to the nanotube surface due to π-stacking effect, whereas the DETA molecule had a repulsive interaction with the single-walled nanotubes. The interaction energies of the molecular systems were also calculated. Furthermore, an affinity index (AI) of the average distance between the atoms of the resin molecule and nanotube surface was defined to quantify the affinities between the nanotubes and resin molecules. The MD simulation results show that the EPON 862/EPI-CURE W curing agent system has good affinities with single-walled nanotubes.

scholarly journals Study on Strengthening Mechanism of Epoxy Resin/Rubber Concrete Interface by Molecular Dynamics Simulation

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Lijuan Li ◽  
Dajing Qin ◽  
Zhijun Xu ◽  
Yong Feng
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Epoxy Resin ◽  
Interaction Energy ◽  
Mean Square Displacement ◽  
Economic Benefits ◽  
Dynamics Simulation ◽  
Cement Matrix ◽  
Rubber Concrete ◽  
Concrete Interface

Rubber concrete has high environmental and economic benefits. However, the difference in the physical and chemical properties of the interface causes a weak interface between rubber and concrete, which limits the use of rubber concrete to a certain extent. Based on the macroexperiment of epoxy resin (EP) modified rubber concrete, from the nanoscale level, three interface models of Rh (natural rubber)/C-S-H, EP/C-S-H, and Rh/EP/C-S-H were constructed by molecular dynamics simulation to explore the interaction between epoxy resin and rubber cement-based interface and reveal its microreinforcement mechanism. The results of interaction energy, radial distribution function, and mean square displacement show that the addition of EP not only improves the interface interaction energy between Rh and C-S-H but also provides a large number of hydrogen bond donors and receptors, promotes the diffusion of Ca, and increases the adhesion between Rh and cement matrix. The results of the analysis of mechanical properties show that the elastic modulus of the rubber concrete interface model is improved and the interface properties are improved after adding EP.

THE "FOLDING" BEHAVIORS OF HOMOPOLYMERS WITH ONE END FIXED

2004 ◽  
Vol 18 (15) ◽  
pp. 2123-2139 ◽  
Author(s):  
BIN XUE ◽  
JUN WANG ◽  
WEI WANG
Keyword(s):  
Molecular Dynamics ◽  
Chain Length ◽  
Conformational Changes ◽  
Canonical Ensemble ◽  
Interaction Strength ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Native Conformation ◽  
Collapse Temperature

We study the "folding" behaviors of homopolymers with one end fixed. By using canonical ensemble molecular dynamics simulation method, we observe the conformational changes during folding processes. Long chains collapse to the helical nuclei, then regroup to helix from the free-end to form the compact conformations through the middle stages of helix-like coil and helix-like cone, while short chains do not apparently have the above mentioned middle stages. Through simulated annealing, the native conformation of homopolymer chain in our model is found to be helix. We show the relations between specific heat C v (T) and radius of gyration R g (T) as functions of temperature, chain length and the interaction strength, respectively. We find that these two quantities match well and can be combined to interpret the "folding" process of the homopolymer. It is found that the collapse temperature Tθ and the native-like folding temperature T f do not change with the chain length in our model, however the interaction strength affects the values of Tθ and T f .

Influence of Carbon Nanotube Aspect Ratio on Glass Transition Temperature of Polymers: A Molecular Dynamics Simulation Study

2015 ◽  
Vol 817 ◽  
pp. 797-802 ◽  
Author(s):  
Cai Jiang ◽  
Jian Wei Zhang ◽  
Shao Feng Lin ◽  
Su Ju ◽  
Da Zhi Jiang
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Md Simulations ◽  
Diglycidyl Ether ◽  
Dynamics Simulation

Molecular dynamics (MD) simulations on three single walled carbon nanotube (SWCNT) reinforced epoxy resin composites were conducted to study the influence of SWCNT type on the glass transition temperature (Tg) of the composites. The composite matrix is cross-linked epoxy resin based on the epoxy monomers bisphenol A diglycidyl ether (DGEBA) cured by diaminodiphenylmethane (DDM). MD simulations of NPT (constant number of particles, constant pressure and constant temperature) dynamics were carried out to obtain density as a function of temperature for each composite system. The Tg was determined as the temperature corresponding to the discontinuity of plot slopes of the densityvsthe temperature. In order to understand the motion of polymer chain segments above and below the Tg, various energy components and the MSD at various temperatures of the composites were investigated and their roles played in the glass transition process were analyzed. The results show that the Tg of the composites increases with increasing aspect ratio of the embedded SWCNT

Sign in / Sign up

Export Citation Format

Share Document