Principle Of NVP Copolymerization

Principle of NVP Copolymerization

The molecular structure of NVP monomer contains vinyl structure, which is easy to undergo polymerization reaction. In addition, NVP monomer is also very easy to copolymerize with other unsaturated monomers containing vinyl to generate polymer compounds containing both NVP structural units and other monomer structural units.

Generally speaking, the performance of high molecular weight copolymers is between the performance of copolymerized monomers, and the performance of copolymers can be regarded as the hybridization result of the performance of the homopolymers of the monomers that constitute it. By utilizing the excellent performance of NVP structural units to copolymerize NVP monomers with other monomers, the performance of copolymers can integrate the characteristics of PVP and other polymers. The research on the copolymerization of NVP with other monomers and the application of its copolymers has the following significance:

1. The functional groups on the molecular structure of NVP are combined with the functional groups on the molecular structure of other unsaturated monomers to obtain a high molecular weight copolymer with multiple functional groups. This copolymer may have unexpected properties and applications, such as improving hydrophilicity, softening point, improving emulsification ability, dyeing ability, reducing the hygroscopicity of copolymers, and making copolymers no longer water-soluble in aqueous solution.

2. Use NVP to graft copolymerize with other polymers, and the modified copolymer has better performance and wider application.

3. Use cheap unsaturated monomers to copolymerize with NVP, and replace expensive PVP with relatively cheap copolymers without changing the application effect.

4. The study of copolymerization of NVP with other unsaturated monomers is also of theoretical significance, which can promote the study of copolymerization theory and copolymerization kinetics.

In addition, the study of NVP copolymers can also broaden the application field of NVP and open up a new path for the application of NVP.

Copolymerized monomers

Many unsaturated compounds with vinyl structures can copolymerize with NVP monomers, such as esters such as propylene acetate and vinyl acetate, ethers such as vinyl phenyl ether and vinyl butyl ether, hydrocarbons such as ethylene and styrene, etc.

Although many NVP copolymers can be obtained by free radical polymerization, there are only a few that are mass-produced in industry at present. Among them, the copolymerization of NVP and vinyl acetate is the most widely used.

Copolymerization method

The copolymerization of NVP and VAc can be carried out by polymerization, solution polymerization or emulsion polymerization, etc. Solvents can be methanol, ethanol, benzene, acetone, ethyl acetate, ethane, etc.

If the components of each comonomer in the copolymer are different, the properties of the copolymer are also different. Therefore, the key issue in the synthesis of NVP copolymers is to control certain copolymerization process conditions to keep the composition of the copolymer within a certain range. Generally speaking, in polymerization engineering, there are two methods to control the composition of the copolymer to keep it constant: one is the conversion rate control method, that is, to select a suitable reaction monomer ratio, and terminate the polymerization when the copolymerization reaction reaches a certain degree. This method is suitable for systems with a relatively flat curve between the copolymer composition and the conversion rate; the second is to use the batch feeding method, that is, to add the faster-reacting monomers in batches to the slower-reacting monomers for polymerization. This method is suitable for systems with a relatively large slope of the curve between the copolymer and the conversion rate. Therefore, when studying the copolymerization reaction of NVP, it is very important to understand the reactivity ratio and copolymerization rate constant of each monomer.