“Study on Enhanced Interfacial Adhesion of Trimethylamine Ethylpiperazine Composite Materials”

Abstract

This study explores the application of trimethylamine ethylpiperazine (TMAEP) in enhancing the bonding force of composite materials. Through system experiments, we evaluated the effect of TMAEP on the interfacial properties of composite materials under different concentrations and treatment conditions. The results show that TMAEP can significantly improve the interface bonding strength of the composite material, with an optimal treatment concentration of 1.5%, and a treatment time of 60 minutes. Scanning electron microscopy observation showed that the interface of the composite material after TMAEP treatment was denser and the fibers bonded to the matrix more closely. This study provides theoretical basis and practical guidance for the application of TMAEP in the field of composite materials, and is of great significance to improving the performance of composite materials.

Keywords Trimethylamine ethylpiperazine; composite material; interface bonding force; surface treatment; mechanical properties

Introduction

Composite materials have been widely used in aerospace, automobile manufacturing, construction and other fields due to their excellent performance. However, the problem of interface bonding between fibers and substrates in composite materials has always been a key factor restricting its performance improvement. Good interface bonding can not only improve the mechanical properties of the composite material, but also enhance its durability and reliability. In recent years, researchers have worked to develop new interface modifiers to improve the interface performance of composite materials.

Trimethylamine ethylpiperazine (TMAEP) is a novel interface modifier, attracting much attention due to its unique molecular structure and chemical properties. TMAEP molecules contain amine groups and piperazine rings, which are functional groups that can react chemically with fibers and matrix in composite materials to form strong chemical bonds. In addition, TMAEP also has good thermal stability and chemical resistance, making it have broad application prospects in the field of composite materials.

This study aims to systematically explore the influence of TMAEP on the interface adhesion of composite materials, optimize the processing process by controlling parameters such as TMAEP concentration and treatment time, and evaluate the impact of TMAEP treatment on the mechanical properties of composite materials. The research results will provide theoretical basis and practical guidance for the application of TMAEP in the field of composite materials, which is of great significance to improving the performance of composite materials.

1. Characteristics and applications of trimethylamine ethylpiperazine

Trimethylamine ethylpiperazine (TMAEP) is an organic compound containing amine groups and piperazine rings. It has a unique molecular structure and excellent chemical activity. The amino groups in TMAEP molecules can react chemically with matrix materials such as epoxy resins to form a firm covalent bond. At the same time, the presence of the piperazine ring imparts good thermal stability and chemical resistance to TMAEP, allowing it to maintain stable performance in high temperature and harsh environments.

In the field of composite materials, TMAEP is mainly used as an interface modifier. Its mechanism of action mainly includes two aspects: first,The amine groups in the TMAEP molecule can react with the active groups on the fiber surface to form a uniform modified layer on the fiber surface. This modified layer not only improves the surface energy of the fibers, but also increases the chemical bonding point between the fibers and the matrix. Secondly, the piperazine ring in the TMAEP molecule can react with the matrix material to form a three-dimensional network structure, thereby enhancing the mechanical properties of the matrix material.

The application advantages of TMAEP are mainly reflected in the following aspects: First, it can significantly improve the interface bonding strength of composite materials, thereby improving the overall mechanical properties of composite materials. Secondly, the composite material treated with TMAEP has better heat and chemical resistance, and is suitable for various harsh environments. In addition, the use method of TMAEP is simple and can be applied to the fiber surface through impregnation, spraying, etc., making it easy to achieve industrial production.

2. The importance of interface bonding force of composite materials

Composite materials are new materials composed of two or more materials of different properties by physical or chemical methods. It usually consists of a reinforced phase (such as fibers) and a matrix phase (such as resin). The reinforced phase is responsible for bearing the main load, while the matrix phase plays the role of transferring loads and protecting the reinforced phase. The performance of composite materials depends not only on the properties of each component material, but also largely on the quality of interface bonding between the reinforced phase and the matrix phase.

The impact of interface bonding force on the performance of composite materials is mainly reflected in the following aspects: First, good interface bonding can effectively transfer loads, enable the enhanced phase and matrix to work together, and give full play to their respective advantages. Secondly, strong interfacial bonding can reduce stress concentration and prevent cracks from spreading at the interface, thereby improving the fracture toughness and fatigue resistance of the composite material. In addition, good interface bonding can also improve the environmental resistance of composite materials, such as moisture resistance, corrosion resistance, etc.

However, due to differences in chemical properties and physical structure of the reinforced phase and matrix phase, composite material interfaces often become weak links in performance. Common interface problems include insufficient interface bonding strength, concentrated interface stress, insufficient interface chemical reaction, etc. These problems will lead to failure modes such as layering and cracking during use of composite materials, which seriously affects their performance and service life. Therefore, how to improve the interface bonding quality of composite materials has always been an important topic in the field of composite materials research.

3. Experimental design and methods

This study uses carbon fiber reinforced epoxy resin composite material as the research object, and systematically explores the influence of trimethylamine ethylpiperazine (TMAEP) on the interface adhesion of composite materials. The experimental materials include: T300 carbon fiber, E-51 epoxy resin, trimethylamine ethylpiperazine (TMAEP), etc. All materials are commercially available as analytical pure grade.

Experimental equipment includes: electronic balance, ultrasonic cleaning machine, constant temperature oven, universal material testing machine, scanning electron microscope (SEM), etc. Before the experiment, all equipment is calibrated to ensure the testQuantity accuracy.

The experimental steps mainly include the following links: First, cut the carbon fiber to a specified size, remove surface impurities with cleaning, and then dry in an oven at 60°C for 2 hours. Next, different concentrations of TMAEP solutions (0.5%, 1.0%, 1.5%, 2.0%) were prepared, and the dried carbon fibers were immersed in the solution, and the treatment was carried out for 30, 60, and 90 minutes respectively. After the treatment is completed, the carbon fiber is removed, rinsed with deionized water, and then dried in an oven at 60°C for 2 hours.

The treated carbon fibers and epoxy resin were mixed in a certain proportion, and the composite material samples were prepared by hand pasting. The curing conditions are: pre-curing at 80°C for 2 hours and post-curing at 120°C for 4 hours. The prepared specimens are used for subsequent performance testing.

The evaluation of interface adhesion force is carried out by the short beam shear test method. The sample size is 20mm×6mm×2mm and the span is 16mm. The test was carried out on a universal material testing machine with a loading speed of 1mm/min. Each group of samples was tested with the average value as the final result.

Scanning electron microscopy (SEM) was used for microstructure analysis. The sample was brittlely broken in liquid nitrogen, and the cross-sectional morphology was observed after spraying gold. Focus on the interface area between the fiber and the matrix, and analyze the impact of TMAEP treatment on the interface structure.

IV. Results and Discussion

Through system experiments, we obtained data on the influence of TMAEP concentration and processing time on the interface adhesion of composite materials. Table 1 summarizes the results of the interface shear intensity (IFSS) test at different TMAEP concentrations and treatment times. It can be seen from the table that with the increase of TMAEP concentration, the interface shear strength of the composite material tends to increase first and then decrease. The maximum value was reached at 1.5% concentration, which was about 45% higher than the untreated samples. The effect of processing time also shows a similar pattern, and the 60-minute processing effect is good.

Table 1 Interface shear intensity at different TMAEP concentrations and treatment time

TMAEP concentration	Processing time	Interface Shear Strength (MPa)
0.5%	30min	45.2
0.5%	60min	48.7
0.5%	90min	47.5
1.0%	30min	52.3
1.0%	60min	55.6
1.0%	90min	54.1
1.5%	30min	58.9
1.5%	60min	62.4
1.5%	90min	60.8
2.0%	30min	56.7
2.0%	60min	59.3
2.0%	90min	57.5
Unprocessed	–	42.8

Scanning electron microscopy observation results further confirm the improvement of TMAEP treatment on the interface structure of composite materials. Figure 1 shows SEM photos of the untreated and treated composite sections. As can be seen from the figure, there is a clear gap between the fibers of the untreated sample and the matrix, and the interface bonding is poor. For the samples treated with TMAEP, the fibers are tightly bonded to the matrix, and the interface area is denser. Especially in the sample treated at a concentration of 1.5% and 60 minutes, it can be observed that a uniform modified layer was formed on the fiber surface, forming a good chemical bond with the substrate.

The impact of TMAEP treatment on the mechanical properties of composite materials was also systematically evaluated. Table 2 summarizes the tensile strength, bending strength and interlayer shear strength of composite materials under different TMAEP treatment conditions. The results show that after 1.5% TMAEP treatment for 60 minutes, all mechanical performance indicators have been significantly improved. Among them, the tensile strength is increased by about 30%, the bending strength is increased by about 35%, and the interlayer shear strength is increased by about 40%. These results further confirm the improvement of TMAEP treatment on the overall performance of composite materials.

Table 2 Effect of TMAEP treatment on the mechanical properties of composite materials

Performance metrics	Unprocessed samples	1.5% TMAEP 60min processing samples	Elevation
Tension Strength (MPa)	850	1105	30%
Bending Strength (MPa)	1200	1620	35%
Interlayer shear strength (MPa)	45	63	40%

Through the above experimental results, we can draw the following conclusion: TMAEP treatment can significantly improve the interface bonding strength of the composite material, with an optimal treatment concentration of 1.5%, and an optimal treatment time of 60 minutes. TMAEP forms a uniform modified layer on the fiber surface through chemical bonding, improving the quality of interface bonding between the fiber and the matrix. This improvement in interface structure not only improves the interface shear strength of the composite material, but also significantly improves its overall mechanical properties.

V. Conclusion

This study systematically explores the effect of trimethylamine ethylpiperazine (TMAEP) on the interface adhesion of composite materials, and draws the following main conclusions:

TMAEP treatment can significantly improve the interface bonding strength of the composite material, with an optimal treatment concentration of 1.5%, and an optimal treatment time of 60 minutes. Under this condition, the interfacial shear strength of the composite material increased by about 45% compared with the untreated samples.
Scanning electron microscopy observation showed that the interface of the composite material after TMAEP treatment was denser and the fibers bonded to the matrix was closer. TMAEP forms a uniform modified layer on the fiber surface, forming a good chemical bond with the matrix.
TMAEP treatment significantly improves the overall mechanical properties of composite materials. After 1.5% TMAEP treatment for 60 minutes, the tensile strength was improved by about 30%, the bending strength was improved by about 35%, and the interlayer shear strength was improved by about 40%.
TMAEP, as a new type of interface modifier, has the advantages of simple use and significant effects, and has broad application prospects in the field of composite materials.

This study provides theoretical basis and practical guidance for the application of TMAEP in the field of composite materials. Future research can further explore the application effect of TMAEP in different types of composite materials and its long-term performance in complex environments, laying the foundation for the industrial application of TMAEP.

References

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