Large-particle size monodisperse

Vanderhoff et al. prepared large-particle size monodisperse latexes on the Space Shuttle (55). These latexes were made from large colloidal droplets consisting primarily of monomers that were polymerized. Droplets of similar size could not be maintained on the ground for sufficient duration due to sedimentation. 

For monodisperse systems in the large particle size regime, where the extinction efficiency can be assumed constant and approximately equal to 2, equation 2 becomes... 

Prior to the measurements of the different reactor latex samples the computerized HDC was calibrated for particle-size using the standard procedure (3) and also for particle-size distribution quantification. For the particle-size distribution calibration two different particle-size monodisperse carboxylated S/B latexes were polymerized. Various mixtures of these latexes were prepared by blending the large 2100A and the small 700A latexes in different ratios by weight 60/40, 70/30, 80/20 and 90/100 respectively. 

There are several bottom-up methods for the preparation of nanoparticles and also colloidal nanometals. Amongst these, the salt-reduction method is one of the most powerful in obtaining monodisperse colloidal particles. Electrochemical methods, which gained prominence recently after the days of Faraday, are not used to prepare colloidal nanoparticles on a large scale [26, 46], The decomposition of lower valent transitional metal complexes is gaining momentum in recent years for the production of uniform particle size nanoparticles in multigram amounts [47,48],... 

PAMAM dendrimers are large (G4 is 4.5 nm in diameter) and have a hydrophilic interior and exterior accordingly, they are soluble in many convenient solvents (water, alcohols, and some polar organic solvents). Importantly, the interior void spaces are large enough to accommodate nanoscopic guests, such as metal clusters, and are sufficiently monodispersed in size so as to ensure fairly uniform particle size and shape. As we will show later, the space between the ter-... 

Preparation of Monodisperse and Clean Latices. In the polymerization described above, conditions with relatively high f s were adopted to make clear the behavior of M2 in the reaction course. The resulting latices contain a fairly large amount of polymer dissolved in the serum. It was also clarified that addition of an excess amount of M2 monomers makes the particle-size distribution widespread. Some polymerizations of St with a small amount of HMA were carried out to obtain monodisperse latices free from the polymer dissolved in the serum. 

Ha et al. [93,94] prepared monodisperse polymer microspheres from 1 to 40 pm in diameter for medical diagnostic tests, as chromatography column packing and as calibration standards. The work deals with the synthesis of large and uniform poly (butadiene-styrene) latex. The ceramic SPG membrane, with a pore diameter of 1.6 pm, was employed. The uniform particle sizes were in the diameter range of 4-6 pm. 

The particle-sizes and particle-size distribution of the two monodisperse carboxylated S/B latexes are shown in the hydrodynamic chromatograms of Figure 1. The average diameters of the large, Df, and the small, Dg, relatively monodisperse latexes were 2100A and 720Arespectively. 

In the seeded emulsion polymerization of some monomers —e.g., styrene—it is possible to obtain final latexes with uniform, large particles by adjusting, during polymerization, the quantity of added emulsifier the formation of new particles is prevented by the limited amount of emulsifier. For vinyl chloride, limited emulsifier is not sufficient to prevent the formation of new particles in fact, to obtain a monodispersed latex, the surface of the particles seeded in a given water volume must be controlled. It is assumed that the growth of new nuclei is related either to the rate of formation of primary useful radicals or to the rate that these are taken by the surface of sized particles. 

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