Catalytic mechanism and experimental analysis of dibutyltin dilaurate during the vulcanization process

Introduction

Dibutyltin dilaurate (DBTDL), as an efficient catalyst, is widely used in the rubber vulcanization process. This article will explore the catalytic mechanism of DBTDL in the vulcanization process and analyze its specific role in rubber vulcanization through experiments.

1. Catalytic mechanism of dibutyltin dilaurate

1. Overview of vulcanization reactions

   • Vulcanization reaction: Rubber vulcanization refers to the process of adding sulfur or other cross-linking agents to rubber to form a three-dimensional network structure through a chemical reaction at a certain temperature. This process can significantly improve the physical and mechanical properties of rubber, such as hardness, tensile strength and wear resistance.
   • Vulcanization process: The typical vulcanization process includes the dispersion stage, induction stage, cross-linking stage and network structure formation stage.

2. The catalytic effect of DBTDL

   • Accelerate the vulcanization reaction: As a catalyst, DBTDL can significantly accelerate the vulcanization reaction, shorten the vulcanization time, and improve the vulcanization efficiency.
   • Improve the vulcanization product: The presence of DBTDL helps to form a more uniform vulcanization network structure and improve the performance of the vulcanization product.

3. Analysis of catalytic mechanism

   • Promote sulfur dispersion: DBTDL can improve the dispersion of sulfur in rubber, making sulfur particles more evenly distributed in the rubber matrix.
   • Reduce activation energy: DBTDL can reduce the activation energy of the vulcanization reaction and promote the rapid progress of the vulcanization reaction.
   • Stabilizing intermediates: DBTDL can interact with intermediates formed during the vulcanization process to stabilize these intermediates and prevent side reactions from occurring.

2. Experimental analysis

In order to better understand the catalytic effect of DBTDL in the rubber vulcanization process, we can analyze it through a series of experiments.

Experimental design

1. Experimental materials

   • Natural Rubber (NR): As a base material.
   • Sulfur: Acts as a cross-linking agent.
   • DBTDL: Acts as a catalyst.
   • Other additives: such as accelerators, fillers, etc.

2. Experimental Equipment

   • Open mixer: used for mixing rubber.
   • Plate vulcanizer: used to vulcanize rubber.
   • Electronic universal testing machine: used to test the mechanical properties of vulcanized rubber.
   • Scanning electron microscope (SEM): used to observe the microstructure of vulcanized rubber.

3. Experimental steps

   • Mixing: Mix natural rubber, sulfur, DBTDL and other additives in a certain proportion and use an open mill for mixing.
   • Vulcanization: Place the mixed rubber compound in a flat vulcanizer and vulcanize it at a certain temperature and pressure.
   • Testing: After vulcanization is completed, use an electronic universal testing machine to test the mechanical properties of the vulcanized rubber, such as tensile strength, elongation at break, etc.
   • Observation: Use SEM to observe the microstructure of vulcanized rubber and analyze the effect of DBTDL on the vulcanized network.

Experimental results and analysis

1. Vulcanization time comparison

   • Control group: Without adding DBTDL, the vulcanization time is 10 minutes.
   • Experimental group: After adding DBTDL, the vulcanization time was shortened to 7 minutes.
   • Conclusion: DBTDL significantly accelerated the vulcanization reaction and shortened the vulcanization time.

2. Mechanical property testing

   • Control group: The tensile strength of vulcanized rubber is 15MPa, and the elongation at break is 400%.
   • Experimental group: After adding DBTDL to the vulcanized rubber, the tensile strength increased to 18MPa and the elongation at break increased to 450%.
   • Conclusion: The addition of DBTDL improves the mechanical properties of vulcanized rubber.

3. Microstructure Observation

   • Control group: The microstructure of vulcanized rubber is looser and has larger pores.
   • Experimental group: The vulcanized rubber after adding DBTDL has a denser microstructure and reduced pores.
   • Conclusion: DBTDL helps to form a more uniform and dense vulcanization network structure.

3. Experimental data and charts

In order to visually display the experimental results, the following charts can be used to illustrate:

1. Vulcanization time comparison chart

   • Compare the changes in vulcanization time before and after adding DBTDL.

2. Mechanical properties comparison chart

   • Show the changes in tensile strength and elongation at break of vulcanized rubber before and after adding DBTDL.

3. SEM photos

   • Show the microstructural differences between the vulcanized rubber in the control group and the experimental group.

4. Conclusion and outlook

Through the catalytic mechanism of DBTDL in the rubber vulcanization process and its experimental analysis, we draw the following conclusions:

1. Remarkable catalytic effect: DBTDL can significantly accelerate the vulcanization reaction and shorten the vulcanization time.
2. Obvious performance improvement: The addition of DBTDL improves the mechanical properties of vulcanized rubber, such as tensile strength and elongation at break.
3. Microstructure optimization: DBTDL helps to form a more uniform and dense vulcanization network structure and reduce pores.

Future research directions will focus more on developing environmentally friendly catalysts to reduce the impact on the environment. In addition, by further optimizing the usage conditions of DBTDL, such as addition amount, reaction temperature, etc., its catalytic effect can be further improved and provide technical support for the development of the rubber industry.

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This article provides a detailed introduction to the catalytic mechanism of dibutyltin dilaurate during rubber vulcanization and its experimental analysis. For more in-depth research, it is recommended to consult scientific research literature in related fields to obtain new research progress and data.

Extended reading:

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