Effect of nanoparticles on mechanical properties in composite coated materials enhanced by metal nanoparticles

The development of modern high-tech urgently needs high-performance materials with low elastic modulus, high yield strength, and large elastic strain performance. However, traditional metal materials lack the characteristics of combining the advantages of these high-performance materials. The metal nanoparticles, with super large elastic strain and ultra-high yield strength, enhance the incomparable superior performance of traditional single materials and have a wide application prospect in many modern high-tech industries. In addition, the nanoparticles will reunite in the collective, which has a certain impact on the mechanical properties of the composite coating materials. Several metal nanoparticles were selected as reinforcing materials and epoxy resin polymer as a matrix material to explore and analyze the influence of nanoparticles in the composite coating materials of metal nanoparticles. The hydrothermal method was used to enhance the properties of the epoxy resin polymer, disperse the epoxy resin, make the Huangyang resin composite coating, and study the effect of nanometer content on the mechanical properties of the composite coating. According to the research results, the appropriate amount of nanometers can optimize the performance of the coating of epoxy resin. When the number of nanoparticles added is 0.05%, the mechanical properties of the coating reach the best.


Introduction
The composite coating material of metal nanostructure is a new type of material, with strong operability and high performance in line with the actual needs of modern technology development, which provides a wider range of material selectivity for the development of modern technology.As a typical composite coating material, to predict the influence of nanoparticles on mechanical properties, it is necessary to understand the mechanical properties of nanometers and predicted nanoparticles.We should recognize that there is an influence in the interphase relative to the properties of the composite.The interphase refers to an area surrounded by the nanoparticles and occupies a large volume fraction, and the mechanical properties will change with the presence of the nanoparticles.The agglomeration of nanoparticles enhances the possibility of their mechanical properties [1] .Therefore, in the process of studying the mechanical properties of metal nanoparticles, the type, size, interphase, and dispersion of nanoparticles should be used as important parameters to affect the properties of composite coating materials of nanoparticles.
EP has good mechanical properties, and its good bonding and electrical properties are widely used in the aerospace industry, electronics and construction industry, and many other fields, but after curing the three-dimensional mesh structure, the EP material has higher cross-linking density.In brittleness, rigidity, fatigue resistance, toughness, and plasticity, there are some deficiencies, which limit the EP material used in a wider range of fields.Metal nano with small particle size, large surface area, thermal conductivity, and dispersion is good.It is mixed with EP material, and the surface of the unpaired atoms is more.The possibility of physical or chemical reaction with EP material can effectively enhance the mechanical properties of the EP matrix, with nanoparticles with the toughness of the EP material polymer TiO TiO TiO TiO (as shown in Figure Figure 1) [2] .

Model construction principle
The model constructed in this paper mainly uses bisphenol A epoxy resin, whose monomer and curing agent are bisphenol A diglycidyl ether (DGEBA) and diamino diphenylsulfone (33 DDS), respectively.The molecular structure of bisphenol A epoxy resin is shown in At the same time, MS (Materials Studio) is used as the model modeling tool.The total energy of the molecular system in the modeling process is the vibration energy; the bond length and bending vibration energy; the bond angle torsion energy; the vibration energy; cross valence bond interaction energy; hydrogen bond interaction energy; hydrogen bond interaction energy; electrostatic interaction energy: van der Waals interaction energy.
In the MS modeling tool, the molecular model is constructed according to the molecular structure formula of Figure 1, and then the structure is optimized to obtain the optimized 3-D molecular model [3].
The metal nanoparticles, as a curing agent, associate with the epoxy matrix of the EP monomer through its functional group (-) or form a three-dimensional mesh structure.The mechanism effect of the connection reaction between the metal nanoparticles and the EP monomer is shown in Figure 2 [4].As shown in Figure 3, each epoxy monomer has two epoxy groups, and the curing agent molecule formed has two amino groups, while the resulting amino group has two epoxy groups resulting in a connection reaction, thus forming the cross-linking between the EP polymers [5].

2.1Reaction process of the epoxy monomers with the NH group
As shown in Figure 3a, the reaction process between the epoxy monomer and the group occurs.After the opening of the oxygen end of the epoxy monomer, the epoxy monomer contacts a nanoparticle to form a covalent bond in the curing agent molecule.In the secondary reaction process between the epoxy monomer and the NH group shown in Figure 3b, the two epoxy groups connected in each epoxy monomer can form two amino groups on the curing agent, and each amino group can react with the two epoxy groups to form the fusion of the EP polymer [6].

Model building process
First, according to the principle of the model construction, the reaction occurs between an amino group and two epoxy groups, so the ratio of epoxy resin monomer and curing agent is 2:1.According to this principle, the model building tool MS can be 60 DGEBA and 3033 DDS periodic changes to perform scripts to achieve complex modeling operations.

Mark the reaction atoms
The reaction atoms of the built molecular model are labeled, and the specific process is shown in Figure 4, where the white atoms are H atoms and the gray atoms are C atoms, and the reaction sites of DGEBA and 33 DDS are marked at certain positions.

MS execution script
The 60 DGEBA and 3033 DDS after the labeled reaction point were put into the periodic box and then read into the reaction atoms list.After setting the distance, we judged whether paired Rc and Rn would exist within the reaction distance.If the two start the crosslinking reaction, then the paired reaction atoms are connected, and the list of reaction atoms is updated.If the reaction distance is not reached, the reaction distance is further judged until the maximum reaction distance or the target crosslinking degree is reached [7].

Establishment, the nanotube model 𝑇𝑖𝑂
A nanotube model of 2 nm length and diameter of 7 A (1 A=) was constructed and fused in epoxy resin to create a model with the mass percentage of the nanotube of 9.6% based on the crosslinking reaction.In addition, molecular simulation software is used to calculate the key physical properties, determine the current connection between any two atoms, and ensure the fracture and generation of interatomic bonds.The expression is the bond energy and the coordinated energy correction term; valence energy term, penalty energy direction, torque energy term, molecular conjugate action term, non-bonded van der Waals force action term, and non-bonded coulomb force action term are , respectively [8].The intellectual education temperature of the model is 300 K, the step value is 0.25 fs, and the relaxation of 100 ps.The density structure of the model is closer to the actual situation of constant temperature and pressure relaxation, to ensure the stability and reliability of the final calculated mechanical properties.

Mechanical performance calculation
The Mechanical performance calculationis optimized after using a small strain in the elastic limit.According to the above method, the stiffness matrix of the model is calculated many times, and the second derivative of the potential energy corresponding edge is: In Equation ( 1), U is the potential energy; it is the stress, which is the first derivative corresponding to the potential energy per unit volume."+" and "-" represent the stretch and contraction values.
For the EP in this model and the EP polymer passing materials optimized by the nano model, the constant λ and μ of the two Game names can be obtained from their rigidity matrix (such as Equation ( 2)) [9] .
According to Equation (2), Young's modulus E, shear modulus G, volume modulus B, and Poisson ratio V can be obtained (as shown in Equation ( 3)).
To investigate the mechanical properties of EP polymer of the nanotube model under different temperature conditions, the pressure spacing of 50 K intervals kept the pressure range from 300 to 700 K, which is the mechanical properties of the nanotube model at 9 interval temperature values, and the mechanical properties of 5 sets of polymer systems (as shown in Table 1 3, the mechanical properties of optimized EP polymer at 300 K are compared with those of ordinary EP materials.It can be seen that the density, Young's modulus, shear modulus, and Poisson ratio of optimized metal nanoparticles are similar to the modulus value of ordinary EP materials, while the intersection of the volume modulus is large.This is because the polymerization of the nanoparticles and the EP materials associate with the reaction to form a more rigid EP polymer, that is, the mechanical properties of the last fused EP materials will be better [10].

Conclusion
In conclusion, the nanotube model is constructed by using the modeling tool MS and gives molecular dynamics simulation to calculate the key mechanical properties of nanoparticles in EP materials.The simulation experiment results can be obtained through the article selected nanoparticles as doping particles of epoxy resin composite coating material, optimize the mechanical properties of the EP material, effectively broaden the application scope of EP material in new technology products, and are the alternative materials of surface charge accumulation.The results of the study to enhance metal nanoparticles of composite coating material mechanical properties research do effective reference and promote the improvement of related technology.

Figure 3 .
Figure 3.Effect diagram of the ligation reaction mechanism.

Table 1 .
). TiO Simulation results of the mechanical properties of the nanotube model.
5According to Table