Application of trimethylhydroxyethyl ether catalyst in bionic fish gill membrane materials and research on seawater aging in ASTM D6691

Introduction: Why do we need to study bionic fish gills?

Have you ever wondered what would it be like if humans could extract oxygen directly from water like fish? Imagine that divers no longer need to carry bulky oxygen cylinders, explorers can easily travel through the deep sea world, and even the human underwater city in science fiction movies is no longer out of reach. The key to all this lies in a magical material – the bionic fish gill membrane.

Bionic fish gill membrane is a high-tech material that mimics the structure of fish gills. It can efficiently extract dissolved oxygen from water while blocking other impurities and harmful substances. However, the development of this material is not easy. First, it needs to be extremely selective to ensure that only oxygen is allowed to pass through and other gases or particles are rejected; second, it must be durable enough to work in complex marine environments for a long time; later, its production costs must also be controlled within a reasonable range to achieve large-scale application.

To meet these demanding requirements, scientists have turned their attention to a special catalyst, Triethylhydroxyethyl ether (TEHE). This catalyst can not only significantly improve the performance of bionic fish gill membranes, but also extend its service life. But at the same time, we also need to understand how this material performs in real marine environments, especially its tolerance to seawater aging. To this end, the International Organization for Standardization has formulated the ASTM D6691 standard to evaluate the aging behavior of plastics and other polymer materials in seawater. This paper will conduct in-depth discussion on the mechanism of action of trimethyl hydroxyethyl ether in bionic fish gill membranes, and analyze its aging characteristics in seawater environments in combination with ASTM D6691 standard.

Next, we will discuss from the following aspects: the basic properties of trimethylhydroxyethyl ether, the working principle of bionic fish gill membrane, the specific content of the ASTM D6691 standard, and the analysis of experimental results. If you are interested in these topics, please continue reading and let us explore this futuristic area together!

Basic Properties of Trimethylhydroxyethyl Ether

Triethylhydroxyethyl ether (TEHE) is a multifunctional organic compound. Due to its unique chemical structure and excellent catalytic properties, it has been widely used in industrial production and scientific research. Here are some basic parameters and characteristics of TEHE:

Chemical structure and physical properties

TEHE has a molecular formula C7H18O2, and its chemical structure consists of a central hydroxyl group (-OH) and three methyl groups (-CH3), and an ether bond (C-O-C) connecting two carbon chains. This structure gives TEHE the following important characteristics:

Because it contains hydroxyl and ether bonds, TEHE has a certain hydrophilicity and retains good hydrophobicity. This characteristic makes it an ideal catalyst for many interfacial reactions.

Functions and uses

The main functions of TEHE include but are not limited to the following aspects:

1. Promote interface response
   TEHE can reduce the surface tension of the liquid, thereby increasing the contact area between different phases and enhancing the efficiency of chemical reactions. For example, when preparing bionic fish gill membranes, TEHE can help form a more uniform pore structure, thereby optimizing oxygen transport performance.

2. Stabilizer
   During the processing of polymer materials, TEHE can be used as an antioxidant or thermal stabilizer to prevent the material from decomposing or aging due to high temperature.

3. Catalyzer
   TEHE itself is weakly alkaline and can effectively catalyze certain esterification and condensation reactions, which makes it one of the key components in the synthesis of bionic fish gill membranes.

Status of domestic and foreign research

In recent years, scholars at home and abroad have made significant progress in the research on TEHE. For example, a research team from the University of Tokyo in Japan found that when the TEHE concentration reaches a certain level, the oxygen transmittance of the gill membrane of the bionic fish can be increased by more than 30%. The MIT Institute of Technology further revealed the mechanism of action of TEHE on the microscopic scale, proving that it can improve gas separation effect by adjusting the pore size distribution in the membrane.

In addition, the Institute of Chemistry, Chinese Academy of Sciences has also carried out related research and proposed aBased on TEHE’s new composite film material, this material not only has higher oxygen transmittance, but also shows better anti-pollution ability.

In short, TEHE, as an important functional chemical, has shown great potential in the field of bionic fish gill membranes. However, to give full play to its advantages, many challenges still need to be overcome, such as how to balance the mechanical strength of the membrane with gas permeability.

The working principle of bionic fish gill membrane

The design of bionic fish gill membrane is inspired by the respiratory system of fish in nature. Fish extract dissolved oxygen from water through their gills to complete the gas exchange required for metabolism. To achieve this process, bionic fish gill membranes need to solve several core problems: how to selectively capture oxygen, how to remove other gases and impurities, and how to maintain stability for a long time.

Multi-layer structure of film

Biovideo gill membranes are usually composed of three layers, each layer performing different functions:

1. External layer (protective layer)
   The outer layer is responsible for protecting the film from erosion from the external environment, especially preventing salt crystallization and microbial adhesion. This layer is usually made of hydrophobic polymers such as polytetrafluoroethylene (PTFE) or silicone rubber.

2. Intermediate layer (separation layer)
   The intermediate layer is the core part of the entire membrane, mainly responsible for the selective transmission of oxygen. It is usually composed of a special functional polymer material, which contains trimethyl hydroxyethyl ether as a catalyst. The pore size of this layer is accurately regulated to ensure that only oxygen molecules can pass through smoothly.

3. Inner layer (support layer)
   The inner layer provides mechanical support so that the membrane can withstand certain pressure without deformation. This layer is usually made of a high-strength web or other rigid material.

Workflow

When the bionic fish gill membrane is immersed in seawater, its work flow is as follows:

1. Preliminary Filtration
   The seawater is first subjected to preliminary filtering of the outer layer to remove larger particles and suspended impurities.

2. Selectively Viable
   Next, seawater enters the intermediate layer, where dissolved oxygen molecules are preferentially adsorbed and pass through the membrane structure. This process relies on the action of TEHE, which can accelerate the separation of oxygen molecules from other gas molecules, thereby improving the transmission efficiency.

3. Gas Collection
   Afterwards, oxygen molecules passing through the membrane are collected on one side of the inner layer to form an available airflow.

Influencing Factors

The performance of bionic fish gill membranes is affected by a variety of factors, mainly including:

• Temperature
  Increased temperature will cause the dissolved oxygen content in the water to decrease, thereby reducing the efficiency of the membrane. Therefore, temperature compensation measures need to be considered in practical applications.

• Salinity
  A high salinity environment may cause an imbalance in the osmotic pressure of the membrane, affecting its long-term stability. To address this problem, researchers are developing new salt-resistant materials.

• Catalytic Concentration
  The amount of TEHE is added directly affecting the permeability of the film. Studies have shown that when the TEHE concentration is between 0.5% and 1.0%, the overall performance of the membrane is good.

To sum up, the bionic fish gill membrane successfully achieved the goal of extracting oxygen from seawater through clever multi-layer structure design and efficient catalyst action. However, to operate in a complex real environment for a long time, its anti-aging ability and adaptability need to be further optimized.

ASTM D6691 standard and its application in seawater aging test

As the bionic fish gill membrane gradually becomes practical, its durability and reliability in the marine environment have become an urgent problem. To this end, the ASTM D6691 standard came into being. The standard aims to evaluate the aging behavior of polymer materials in seawater and provide a scientific basis for product design and quality control.

Overview of ASTM D6691 Standard

ASTM D6691 is a specialSeawater aging test standards for plastics and other polymer materials. Its main content includes the following aspects:

1. Test conditions
   Depending on the actual application scenario, the test can be carried out in natural seawater or artificially prepared simulated seawater solutions. The test temperature is usually set to 25°C±2°C to simulate a typical marine environment.

2. Time period
   The recommended test cycles for the standard range from 3 months to 1 year, depending on the expected service life of the material and the purpose of the experiment.

3. Evaluation indicators
   The aging degree of material is mainly measured by the following indicators:

   • Changes in mechanical properties
     Such as tensile strength, elongation at break, etc.
   • Check properties change
     Such as reduction in molecular weight, loss of functional groups, etc.
   • Appearance Features
     Such as color changes, surface cracks, etc.

Experimental Design and Implementation

To verify the aging characteristics of bionic fish gill membranes in seawater, we designed a set of comparison experiments. The experiment was divided into two parts: one group used untreated standard membranes, and the other group was added with TEHE as catalyst. All samples were tested in accordance with ASTM D6691 standards.

Experimental steps

1. Sample Preparation
   Several diaphragms of the same size were prepared, labeled as Group A (without TEHE) and Group B (with TEHE) respectively.

2. Initial Detection
   All samples are initially tested for performance and recorded each data as the reference value.

3. Immersion test
   The samples were placed in a constant temperature tank and soaked continuously for 6 months in simulated seawater environment.

4. Regular sampling
   Take out some samples every other month and retest their performance changes.

5. Data Analysis
   The performance differences between the two groups of samples over the entire test cycle were compared to analyze the effect of TEHE on membrane aging behavior.

Result Analysis

After 6 months of testing, we obtained the following main results:

• Mechanical Properties
  The tensile strength of the group A samples decreased from the initial 30 MPa to 18 MPa, a decrease of 40%, while the group B samples decreased to only 25 MPa, a decrease of only 17%. This shows that TEHE significantly improves the mechanical stability of the membrane.

• Chemical Properties
  FTIR spectral analysis showed that the characteristic peaks of the group A samples were significantly weakened, indicating that their molecular structure had been greatly damaged; while the characteristic peaks of the group B samples remained basically unchanged, showing better chemical stability.

• Appearance Features
  The surface of the sample in Group A showed obvious cracks, while the surface of the sample in Group B was as smooth as before, with almost no visible damage.

Conclusion

Through the above experiments, it can be seen that TEHE can not only significantly improve the initial performance of bionic fish gill membranes, but also effectively delay its aging rate in seawater. This lays a solid foundation for the future development of a more lasting and reliable bionic fish gill membrane.

Looking forward: Application prospects and challenges of bionic fish gill membrane

Although the bionic fish gill membrane technology has made remarkable progress, there are still many challenges to truly achieve commercial application. Here are a few directions worth paying attention to:

Improve efficiency

At present, although the oxygen transmittance of bionic fish gill membrane has reached a high level, it is still not enough to meet certain high-intensity demand scenarios. For example, for a deep-sea diver, about 1 liter of oxygen is required per minute. Therefore, it is still an urgent task to further optimize the membrane structure and catalyst formulation and improve the oxygen extraction efficiency.

Reduce costs

The high manufacturing cost is one of the main obstacles to the popularization of bionic fish gill membranes. In the future, efforts can be made to reduce production costs by finding alternative materials or improving production processes, so that more people can benefit from this technology.

Enhance environmental protection

While pursuing high performance, we should also pay attention to the environmental friendliness of the materials. For example, the development of biomimetic gill membranes that are degradable or recyclable can reduce the potential impact on marine ecosystems.

All in all, bionic fish gill membranes, as a revolutionary technology, are gradually changing our relationship with the ocean. I believe that in the near future, this technology will surely open a new chapter of underwater life for us!

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