Polyurethane synthesis technology under catalyzed by N,N-dimethylcyclohexylamine
1. Introduction
Polyurethane (PU) is a polymer material widely used in the fields of construction, automobile, furniture, shoe materials, etc. Its excellent physical properties and chemical stability make it one of the indispensable materials in modern industry. In the synthesis of polyurethane, the selection of catalyst is crucial. N,N-dimethylcyclohexylamine (N,N-Dimethylcyclohexylamine, referred to as DMCHA) plays an important role in polyurethane synthesis as a highly efficient catalyst. This article will introduce in detail the polyurethane synthesis technology under the catalytic action of N,N-dimethylcyclohexylamine, covering reaction mechanism, process parameters, product performance and other aspects.
2. Chemical properties of N,N-dimethylcyclohexylamine
N,N-dimethylcyclohexylamine is an organic amine compound with the molecular formula C8H17N and contains cyclohexyl and two methyl substituted amino groups in the structure. Its chemical properties are as follows:
Features | Value/Description |
---|---|
Molecular Weight | 127.23 g/mol |
Boiling point | 159-160 °C |
Density | 0.85 g/cm³ |
Solution | Easy soluble in organic solvents, slightly soluble in water |
Catalytic Activity | Efficient catalyzing of the reaction between isocyanate and polyol |
3. Basic principles of polyurethane synthesis
The synthesis of polyurethane is mainly achieved through addition polymerization reaction between isocyanate and polyol. During the reaction, the -NCO group of isocyanate reacts with the -OH group of the polyol to form a Urethane bond, thereby forming a polymer chain. The reaction equation is as follows:
R-NCO + R'-OH → R-NH-CO-O-R'
Under the catalytic action of N,N-dimethylcyclohexylamine, the reaction rate is significantly improved and the reaction conditions are more mild.
4. Catalytic mechanism of N,N-dimethylcyclohexylamine
N,N-dimethylcyclohexylamine as a catalyst, mainly throughThe following two ways to promote reaction:
- Nucleophilic Catalysis: The nitrogen atom in DMCHA has a lone pair of electrons and can form a transition state with the -NCO group of isocyanate, reduce the reaction activation energy, and accelerate the reaction.
- Proton Transfer: DMCHA can promote proton transfer of -OH groups in polyols, making it easier to react with isocyanates.
5. Polyurethane synthesis process
5.1 Raw material preparation
The main raw materials for polyurethane synthesis include isocyanates, polyols and catalysts. The specific raw material parameters are as follows:
Raw Materials | Type | Molecular Weight | Function |
---|---|---|---|
Isocyanate | MDI (Diphenylmethane diisocyanate) | 250.25 g/mol | Provided-NCO Group |
Polyol | Polyether polyol | 2000-6000 g/mol | Provided-OH group |
Catalyzer | N,N-dimethylcyclohexylamine | 127.23 g/mol | Accelerating the reaction |
5.2 Reaction conditions
The reaction conditions of polyurethane synthesis have an important impact on the performance of the final product. The following are typical reaction conditions:
parameters | value |
---|---|
Reaction temperature | 60-80 °C |
Reaction time | 1-3 hours |
Catalytic Dosage | 0.1-0.5 wt% |
Isocyanate to polyol ratio | 1:1 (molar ratio) |
5.3 Process flow
- Preparation of prepolymers: to diversifyThe alcohol and isocyanate were mixed in proportion, and the catalyst DMCHA was added, and the reaction was carried out at 60-80°C for 1-2 hours to form a prepolymer.
- Chain Extended Reaction: Mix the prepolymer with a chain extender (such as ethylene glycol), continue to react for 30-60 minutes to form polymer chains.
- Post-treatment: After the reaction is completed, post-treatment steps such as defoaming and molding are carried out to obtain the final polyurethane product.
6. Product Performance
The polyurethane catalyzed by N,N-dimethylcyclohexylamine has excellent physical properties and chemical stability. The following are typical product performance parameters:
Performance | value |
---|---|
Tension Strength | 20-40 MPa |
Elongation of Break | 300-600% |
Hardness (Shore A) | 70-90 |
Heat resistance | 120-150 °C |
Chemical resistance | Good |
7. Application areas
Polyurethanes catalyzed by N,N-dimethylcyclohexylamine are widely used in the following fields:
Domain | Application |
---|---|
Architecture | Insulation materials, waterproof coatings |
Car | Seats, dashboards, seals |
Furniture | Sofa, mattress |
Shoe Materials | Soles, insoles |
Electronic | Packaging material, insulation layer |
8. Process Optimization
In order to improve the performance and production efficiency of polyurethane, the process can be optimized by:
- Catalytic Dosage Optimization: Determine the best catalyst through experimentsDosage to avoid excessive or insufficient amount.
- Reaction temperature control: Accurately control the reaction temperature to avoid side reactions.
- Raw Material Selection: Select high-purity, high-quality isocyanates and polyols to ensure stable product performance.
9. Environmental protection and safety
In the process of polyurethane synthesis, the use of N,N-dimethylcyclohexylamine requires attention to environmental protection and safety issues:
- Sweep gas treatment: The waste gas generated during the reaction should be effectively treated to avoid environmental pollution.
- Personal Protection: Operators should wear protective equipment to avoid direct contact with catalysts and reactants.
- Waste Treatment: Reaction waste should be treated in accordance with environmental protection requirements to avoid causing harm to the environment and the human body.
10. Conclusion
N,N-dimethylcyclohexylamine, as a highly efficient catalyst, plays an important role in polyurethane synthesis. Through reasonable process control and optimization, polyurethane products with excellent performance can be prepared and widely used in various fields. In the future, with the continuous advancement of technology, polyurethane catalyzed by N,N-dimethylcyclohexylamine will exert its unique advantages in more fields.
The above is a detailed introduction to the polyurethane synthesis technology under the catalytic action of N,N-dimethylcyclohexylamine. Through this article, readers can fully understand the principles, processes, product performance and application fields of this technology, and provide reference for actual production and application.
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