Influence of the Molecular Mass of Poly(<Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone) on Formation of Cu<Subscript>2</Subscript>O Nanoparticles During Reduction of Divalent Copper Ions with <Emphasis Type="Italic">tert</Emphasis>-Butylamine Borane in Polymer Solution

The process of reduction of divalent copper ions with tert-butylamine borane in dilute aqueous solutions of poly(N-vinylpyrrolidone) is investigated. The influence of polymer molecular mass on properties of the resultant Cu₂O sols is studied. It is shown that Cu₂O nanoparticles with an average diameter of 6–8 nm independent of polymer molecular mass and a relatively narrow size distribution of particles are formed in the systems under study. The contour length of macromolecules and the hydrodynamic diameter of a poly(N-vinylpyrrolidone) macromolecular coil are compared with the diameter of Cu₂O particles. Poly(N-vinylpyrrolidone) with M ≥ 1 × 10⁴ can be used to produce Cu₂O nanoparticles. Poly(N-vinylpyrrolidone) with M > 4 × 10⁴ should be used for the formation of long-living Cu₂O sols.     

Influence of dispersion conditions and nature of the emulsifier on the dispersity and stability of artificial polymer suspensions based on polyetherimide

New methods for producing artificial polyetherimide suspensions in the presence of domestic cationic surfactants, their mixtures, and mixtures of cationic and organosilicon surfactants were proposed. The effect of the polymer concentration in the initial solution and conditions of emulsion dispersion on the stability and particle size of the final polymer suspensions is shown. The colloidal chemical properties of the obtained polymer suspensions are considered. Conclusions about the influence of the nature and concentration of surfactants on the stability of the obtained suspensions are drawn. When using a mixture of cationic and organosilicon surfactants, polymer suspensions stable during production and storage are formed, which is explained by the formation of structural mechanical and electrostatic stability barriers in the surface layers of the particles.