synopsisConventional emulsion polymerization of styrene produces some polydispersion in particle sizes in the latex. By carrying out a onestage polymerization of finely emulsified monomer droplets of styrene formed in a mixture of methanol and water, it is possible to prepare stable latices of polystyrene in which the particles are perfectly uniform in size. The polymer has a relatively low molecular weight, but it is more stable to fragmentation by surfactant solutions than polystyrene prepared by conventional eniulsion polymerization, the molecular weight of which is greater. The surface charge density of the particles is higher than that of particles produced by emulsion polymerization, and this probably accounts for the stability of the dispersion during polymerization and of the latex.
An account is given of an investigation of methods For the fractionation of solvent-extracted wool grease into distinct non-polar, semi-polar, and highly polar groups. The non-polar fraction is conventionally referred to as imoxidized grease and the semi-polar fractions are referred to as oxidized grease. The highly polar fraction possesses strong siirface-aclive properties and is not identilied forthwith as being strictly a part of the grease constituent of raw wool.The methods were applied lo determine quantitatively the extent of oxidation of a wool grease and the amount of amphiphilic or surface-active matter, including synthetic detergents, extracted by the solvent from a wool sample or an aliquot of an aqueous emulsion, in addition, it is demonstrated that ihe amount of methanol-insoluble matter in solvent-extracted wool grease is closely related to, and could be used to predict, the maximum efficiency of recovery of grea,se in a centrifuge.
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