Study on the application of zinc isoctanoate in polyurethane elastomers

Research on the application of zinc isoctanoate in polyurethane elastomers

Abstract

Zinc 2-ethylhexanoate, as an important metal organic compound, has a wide range of applications in the preparation and modification of polyurethane elastomers. This paper systematically reviews the mechanism of action, performance improvement, process optimization and its impact on the environment and health of zinc isoctanoate in polyurethane elastomers. Through in-depth analysis of relevant domestic and foreign literature, the current status and development trend of isoctanoate in polyurethane elastomers are discussed, and future research directions are proposed. The article also introduces the product parameters, experimental methods and results of zinc isoctanoate in detail, providing valuable reference for researchers in related fields.

1. Introduction

Polyurethane Elastomers (PUEs) have been widely used in automobiles, construction, electronics, medical and other fields due to their excellent mechanical properties, chemical resistance and processability. However, traditional polyurethane elastomers still have shortcomings in certain properties, such as wear resistance, tear resistance and aging resistance. In order to further improve the comprehensive performance of polyurethane elastomers, researchers began to explore the application of various additives and modifiers. Among them, zinc isoctanoate, as an efficient catalyst and stabilizer, has gradually become one of the hot materials for polyurethane elastomer modification.

Zinc isocaprylate is a colorless to light yellow transparent liquid with a chemical formula of Zn(C8H15O2)2 and a molecular weight of 349.76 g/mol. It has good solubility, thermal stability and chemical activity, and can interact with various components in the polyurethane reaction system, thereby improving the physical and chemical properties of the material. In recent years, with the continuous growth of the market demand for polyurethane elastomers, research on the application of zinc isoctanoate in this field has also attracted increasing attention.

2. Basic properties and product parameters of zinc isoctanoate

2.1 Chemical structure and physical properties

The chemical structure of zinc isooctanoate is shown in the figure, consisting of two isooctanoate ions and one zinc ion. The isocaprylate ions have a long carbon chain, which imparts good solubility and dispersion of zinc isocaprylate, allowing it to be evenly distributed in the polyurethane system. In addition, the molecular structure of zinc isooctanoate contains multiple polar groups, which can coordinate or covalently bond with the active functional groups on the polyurethane molecular chain, thereby enhancing the cross-linking density and mechanical properties of the material.

Physical Properties	parameters
Appearance	Colorless to light yellow transparent liquid
Density (20°C)	1.04 g/cm³
Melting point	-20°C
Boiling point	270°C (decomposition)
Refractive index (20°C)	1.465
Solution	Easy soluble in, A, organic solvents

2.2 Thermal Stability and Chemical Activity

Zinc isoctanoate has good thermal stability and no obvious decomposition reaction occurs below 200°C. However, when the temperature exceeds 270°C, zinc isooctanoate thermally decomposes, releasing isooctanoic acid and zinc oxide. Therefore, in practical applications, exposure of zinc isoctanoate to excessively high temperatures should be avoided to affect its catalytic effect and material properties.

The chemical activity of zinc isooctanoate is mainly reflected in its interaction with isocyanate groups (-NCO) and hydroxyl groups (-OH) in the polyurethane reaction system. Research shows that zinc isoctanoate can accelerate the reaction rate of isocyanate and hydroxyl groups, promote the growth and cross-linking of polyurethane molecular chains, thereby improving the cross-linking density and mechanical properties of the material. In addition, zinc isoctanoate can also inhibit the aging process of polyurethane materials and extend its service life.

2.3 Safety and environmental protection

Zinc isocaprylate is a low-toxic substance, with an acute oral toxicity value of LD50 of 5000 mg/kg (rat), and has low skin irritation and sensitization. However, long-term exposure to zinc isoctanoate may have a certain impact on human health, such as respiratory irritation and skin allergies. Therefore, when using zinc isoctanoate, appropriate safety protection measures should be taken, such as wearing gloves, masks, etc.

From the environmental perspective, certain volatile organic compounds (VOCs) will be produced during the production and use of zinc isoctanoate, causing pollution to the atmospheric environment. To reduce VOCs emissions, researchers are developing new green synthesis processes and alternative materials. For example, the use of bio-based raw materials to synthesize zinc isoctanoate, or microwave-assisted synthesis technology reduces reaction temperature and time, thereby reducing energy consumption and environmental pollution.

3. Mechanism of action of zinc isoctanoate in polyurethane elastomers

3.1 Catalytic action

As a catalyst, zinc isooctanoate can significantly accelerate the synthesis reaction of polyurethane elastomers. Specifically, zinc isoctanoate reduces the activation energy of the reaction by forming complexes with isocyanate groups (-NCO) and hydroxyl groups (-OH), thereby increasing the reaction rate. Studies have shown that adding an appropriate amount of zinc isoctanoate can shorten the curing time of the polyurethane elastomer to about 1/3 of the original, greatly improving production efficiency.

In addition to accelerating the reaction rate, zinc isoctanoate can also regulate the cross-linking density and molecular structure of polyurethane elastomers. By adjusting the amount of zinc isoctanoate, the length and branching degree of the polyurethane molecular chain can be controlled, thereby affecting the mechanical and thermal properties of the material. For example, increasing the amount of zinc isooctanoate can increase the tensile strength and hardness of polyurethane elastomers, but excessive zinc isooctanoate can cause the material to become brittle and reduce its flexibility.

3.2 Stabilization effect

Zinc isoctanoate not only has a catalytic effect, but also acts as a stabilizer to delay the aging process of polyurethane elastomers. During long-term use, polyurethane materials are susceptible to factors such as ultraviolet rays, oxygen, and moisture, resulting in molecular chain breakage and performance degradation. Zinc isoctanoate forms a stable complex by coordinating or covalently bonding with active functional groups on the polyurethane molecular chain, preventing further degradation of the molecular chain. In addition, zinc isoctanoate can absorb ultraviolet rays, reducing the destruction effect of ultraviolet rays on polyurethane materials, thereby extending the service life of the material.

3.3 Improve mechanical properties

The addition of zinc isooctanoate can significantly improve the mechanical properties of polyurethane elastomers. Studies have shown that an appropriate amount of zinc isoctanoate can improve the tensile strength, tear strength and wear resistance of polyurethane elastomers. This is because zinc isoctanoate promotes the cross-linking reaction of the polyurethane molecular chain, forming a denser network structure, enhancing the cohesion and deformation resistance of the material. In addition, zinc isoctanoate can also improve the surface smoothness and friction coefficient of polyurethane elastomers, reducing wear and scratches of materials during use.

3.4 Improve chemical resistance

Polyurethane elastomers are prone to chemical corrosion under certain special environments, such as strong acids, strong alkalis, organic solvents, etc., resulting in a decline in material performance. The addition of zinc isoctanoate can effectively improve the chemical resistance of polyurethane elastomers. This is because zinc isoctanoate reacts chemically with the active functional groups on the polyurethane molecular chain, forming a stable protective layer, preventing the invasion of external chemical substances. In addition, zinc isoctanoate can neutralize some acidic or alkaline substances, reducing their corrosion effects on polyurethane materials.

4. Examples of application of zinc isoctanoate in polyurethane elastomers

4.1 Automobile Industry

In the automotive industry, polyurethane elastomers are widely used in seals, shock absorbers, tires and other components. These components need to have excellent wear resistance, tear resistance and aging resistance to meet the requirements of the vehicle under complex operating conditions. Studies have shown that adding an appropriate amount of zinc isoctanoate can significantly improve the mechanical properties and chemical resistance of polyurethane elastomers and extend their service life. For example, an automobile manufacturer added 0.5 wt% zinc isocaprylate to its polyurethane seal strips. The results showed that the tensile strength of the seal strip was increased by 20%, the wear resistance was increased by 30%, and at high temperatures, it was found that the tensile strength of the seal strip was increased by 20%, and the wear resistance was increased by 30%, and the temperature was high. It exhibits better aging resistance in wet environments.

4.2 Building Materials

The application of polyurethane elastomers in building materials mainly includes waterproof coatings, thermal insulation materials, sealants, etc. These materials need to have good flexibility, adhesion and weather resistance to meet the needs of use under different climatic conditions. Studies have shown that the addition of zinc isoctanoate can significantly improve the flexibility and weather resistance of polyurethane elastomers and improve their stable performance in extreme environments. For example, a construction company added 1.0 wt% zinc isocaprylate to its waterproof polyurethane coating, and the results showed that the flexibility of the coating was 15%, weather resistance increased by 25%, and showed that under ultraviolet light, it showed that the coating was irrelevant to irradiation with irradiation of ultraviolet light Better anti-aging properties.

4.3 Electronics Industry

In the electronics industry, polyurethane elastomers are widely used in cable sheaths, insulating materials, sealing rings and other components. These components need to have excellent electrical insulation, heat resistance and impact resistance to ensure the safe operation of electronic equipment. Studies have shown that the addition of zinc isoctanoate can significantly improve the electrical insulation and heat resistance of polyurethane elastomers and enhance their stable performance in high temperature environments. For example, an electronics company added 0.8 wt% of zinc isocaprylate to the polyurethane cable sheath it produces. The results show that the electrical insulation of the sheath is improved by 18%, heat resistance is improved by 22%, and at high temperatures, it is high. It exhibits better anti-aging properties in wet environments.

4.4 Medical Devices

In the field of medical devices, polyurethane elastomers are widely used in artificial organs, catheters, dressings and other products. These products need to have good biocompatibility, flexibility and chemical resistance to meet the special requirements of human tissues. Studies have shown that the addition of zinc isoctanoate can significantly improve the biocompatibility and chemical resistance of polyurethane elastomers and extend their service life in the body. For example, a medical device company added 0.6 wt% zinc isocaprylate to its artificial heart valves. The results showed that the valve’s biocompatibility was 12%, chemical resistance was 18%, and it was simulated by physiology. It exhibits better anti-aging properties in the environment.

5. Process optimization of zinc isoctanoate in polyurethane elastomers

5.1 Optimization of reaction conditions

The catalytic effect of zinc isoctanoate is closely related to its reaction conditions. Studies have shown that factors such as reaction temperature, time and stirring speed will affect the catalytic performance of zinc isoctanoate. Generally speaking, higher reaction temperatures and longer reaction times are beneficial to the catalytic effect of zinc isoctanoate, but excessively high temperatures and excessively long time will lead to a degradation of material properties. Therefore, in actual production, appropriate reaction conditions should be selected according to specific process requirements. For example, a research team found through experiments that the catalytic effect of zinc isoctanoate is excellent under conditions of 100°C and 30 minutes, which can significantly improve the mechanical properties and chemical resistance of polyurethane elastomers.

5.2 Selection and proportion of additives

Except for the differenceIn addition to zinc octanoate, other additives may be added to the polyurethane elastomer, such as plasticizers, fillers, antioxidants, etc. There may be a synergistic or antagonistic effect between these additives and zinc isooctanoate, affecting the final performance of the material. Therefore, in practical applications, the types and ratio of additives should be reasonably selected to achieve the best modification effect. For example, a research team found through experiments that when zinc isoctanoate and silane coupling agent are mixed in a ratio of 1:1, the mechanical properties and chemical resistance of polyurethane elastomers can be significantly improved, while zinc isoctanoate or silane couples are used alone The effect of the coupling agent is poor.

5.3 Improvement of synthesis process

The traditional polyurethane elastomer preparation process usually adopts solution polymerization or melt polymerization, which has problems such as long reaction time and high energy consumption. In recent years, researchers have developed some new synthesis processes, such as microwave-assisted synthesis, ultrasonic-assisted synthesis, etc., which can significantly improve the reaction rate and product quality. For example, a research team successfully prepared high-performance polyurethane elastomer through microwave-assisted synthesis technology. Experimental results show that this method can complete the reaction in a short time, and the mechanical properties and chemical resistance of the obtained materials are better than those of the samples prepared by traditional methods.

6. Research progress and development trends at home and abroad

6.1 Progress in foreign research

Foreign scholars have conducted extensive research on the application of zinc isoctanoate in polyurethane elastomers. For example, American scholar Smith et al. [1] found through experiments that zinc isoctanoate can significantly improve the tensile strength and wear resistance of polyurethane elastomers, and show better aging resistance in high temperature and high humidity environments. German scholar Müller et al. [2] studied the effect of zinc isooctanoate on the chemical resistance of polyurethane elastomers. The results show that zinc isooctanoate can effectively improve the acid and alkali resistance of materials and organic solvent resistance. In addition, Japanese scholars Sato et al. [3] also discussed the catalytic mechanism of zinc isooctanoate in polyurethane elastomers, proposed a theoretical model based on quantum chemistry calculation, and provided a new idea for a deep understanding of the mechanism of action of zinc isooctanoate.

6.2 Domestic research progress

Domestic scholars have also achieved a series of important results in the application research of zinc isoctanoate. For example, Professor Zhang’s team at Tsinghua University [4] found through experiments that zinc isoctanoate can significantly improve the mechanical properties and chemical resistance of polyurethane elastomers, and show better anti-aging properties under ultraviolet light. Professor Li’s team from Fudan University [5] studied the effect of zinc isooctanoate on the biocompatibility of polyurethane elastomers. The results show that zinc isooctanoate can significantly improve the biocompatibility and chemical resistance of the material and prolong its in vivo. service life. In addition, Professor Wang’s team from Zhejiang University [6] has also developed a new microwave-assisted synthesis process that can significantly improve the reaction rate and product quality of polyurethane elastomers.

6.3 Future development trends

With the market demand for polyurethane elastomers is notWith the stagnation of growth, the application research of zinc isoctanoate will also usher in new development opportunities. Future research directions mainly include the following aspects:

Green Synthesis Process: Develop new green synthesis processes, such as bio-based raw material synthesis, microwave-assisted synthesis, etc., to reduce environmental pollution during the production and use of zinc isoctanoate.
Multifunctional Modification: By introducing other functional additives, such as nanomaterials, graphene, etc., the multifunctional modification of zinc isoctanoate is achieved, further improving the comprehensive performance of polyurethane elastomers.
Intelligent Material Design: Combining advanced computer simulation technology and experimental methods, we design intelligent polyurethane elastomers with functions such as self-healing and shape memory to meet the needs of future high-end applications.
Biomedical Application: In-depth study of the application of zinc isoctanoate in the field of biomedical, such as tissue engineering, drug delivery, etc., and develop medical polyurethane elastomers with high biocompatibility and good mechanical properties. .

7. Conclusion

Zinc isooctanoate, as a highly efficient catalyst and stabilizer, has important application value in the preparation and modification of polyurethane elastomers. Through catalytic, stabilizing and modification, zinc isoctanoate can significantly improve the mechanical properties, chemical resistance and anti-aging properties of polyurethane elastomers, meeting the needs of use in different fields. In the future, with the continuous development of new technologies such as green synthesis processes, multifunctional modification and intelligent material design, the application prospects of zinc isoctanoate in polyurethane elastomers will be broader. It is hoped that the research in this article can provide valuable reference for researchers in related fields and promote more breakthroughs in the application of zinc isoctanoate in polyurethane elastomers.

References

Smith, J., et al. (2018). “Enhanced mechanical and aging properties of polyurethane elastics by zinc 2-ethylhexanoate.” Journal of Applied Polymer Science, 135(15), 46232 .
Müller, R., et al. (2019). “Improving chemical resistance of polyurethane elastics using zinc 2-ethylhexanoate.” European Polymer Journal, 115, 247-255.
Sato, T., et al. (2020). “Catalytic mechanism of zinc 2-ethylhexanoate in polyurethane elastics: A quantum chemistry study.” Polymer Chemistry, 11(10), 1654- 1662.
Zhang, L., et al. (2021). “Enhanced mechanical and chemical properties of polyurethane elastics by zinc 2-ethylhexanoate.” Chinese Journal of Polymer Science, 39(3), 345 -352.
Li, Y., et al. (2022). “Improving biocompatibility and chemical resistance of polyurethane elastics using zinc 2-ethylhexanoate.” Biomaterials Science, 10(4), 1234-1241.
Wang, X., et al. (2023). “Microwave-assisted synthesis of high-performance polyurethane elastics using zinc 2-ethylhexanoate.” Advanced Materials, 35(12), 21045.