Polyvinyl Acetate (PVAc) is an important raw material for the production of chemicals with a wide range of uses, such as adhesives, coatings, emulsions and so on. In this article, the manufacturing method of Polyvinyl Acetate will be described in detail.
I. Raw material preparation
1. Vinyl Acetate Monomer (Vinyl Acetate, referred to as VAc): Vinyl Acetate Monomer is the main raw material for the production of polyvinyl Acetate, generally produced by ethylene and acetic acid through vinyl acetate synthesis reaction.
2. Initiator: The initiator used to initiate the polymerization of vinyl acetate monomer can be selected from persulfate, azo compounds, etc.
3. Dispersing medium: water or other organic solvents.
II. Polymerization reaction
The manufacture of poly(vinyl acetate) mainly adopts the method of solution polymerization. Specific steps are as follows:
1. Add vinyl acetate monomer, initiator and dispersing medium into the polymerization reactor.
2. Under appropriate temperature and stirring speed, the initiator decomposes to produce free radicals, initiating the polymerization of vinyl acetate monomer.
3. As the reaction proceeds, the polymer molecular chain grows to form polyvinyl acetate.
III. Post-treatment
1. Termination: When the molecular weight of the polymer reaches a predetermined value, a terminating agent is added to terminate the reaction.
2. Dewatering: Remove water remaining in the polymer by vacuum dehydration or centrifugal dehydration.
3. Drying: The dehydrated polymer is dried to obtain the final polyvinyl acetate product.
4. Precautions
1. Strictly control the reaction temperature and stirring speed to ensure the smooth progress of polymerization reaction.
2. Adjust the type and dosage of initiator as needed to control the molecular weight and molecular weight distribution of the polymer.
3. Ensure that the polymer is sufficiently dehydrated and dried during post-treatment to avoid affecting its performance and use.
In conclusion, the manufacturing method of poly(vinyl acetate) involves a number of links and requires strict control of each process parameter to ensure the quality and performance of the final product. By mastering the manufacturing method of polyvinyl acetate, it can provide important raw material support for chemical production and promote the development of related industries.
