α P 616-45-5

Poly vinyl pyrrolidone is obtained from the monomer vinyl pyrrolidone (NVP) through bulk polymerization, solution polymerization and other methods. During the preparation process of bulk polymerization, the viscosity of the reaction system is high, the polymer is not easy to diffuse, and the heat of the polymerization reaction is not easily removed, leading to local overheating. Therefore, the obtained product has low molecular weight, high residual monomer content, and more Yellow, not much practical value. The industry generally uses solution polymerization to synthesize PVP. There are two main routes for PVP production and polymerization. The first is solution polymerization of NVP in an organic solvent, followed by steam stripping.

The second route is aqueous solution polymerization of NVP monomer and water-soluble cationic, anionic or nonionic monomer. Heat the NVP monomer directly above 140℃, or add an initiator to the NVP solution for heating, or add an initiator to the NVP solution (the solvent can be water, ethanol, benzene, etc.) to polymerize by free radical solution, or use it directly PVP homopolymers can be obtained by irradiating NVP monomers or their solutions with light.

Different polymerization methods result in different polymer structures and properties. Among them, the polymer composition and structure obtained by free radical solution polymerization are relatively uniform. The performance is also relatively stable. It is the most commonly used method for NVP homopolymerization. By adjusting the reaction conditions such as monomer concentration, polymerization temperature, and initiator dosage, PVP homopolymers with different molecular weights and different water solubility can be obtained.

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