Intensive agglomeration and microencapsulation of powders

Abstract

Highly concentrated colloidal latex particles from thermoplastics (low-density polyethylene) can be obtained by using phase-inversion emulsification of a polymer melt in which hydrophobically modified water-soluble polymers are used to provide surface activity. Initially, a water-in-polymer-melt emulsion is obtained and subsequently inverted to a polymer-melt-in-water emulsion when a critical aqueous phase volume is reached. After the phase inversion and subsequent dilution of the emulsion, if the solidification of the melt is carried out during mixing, another phase inversion takes place and water-in-solid-polymer aggregates are formed even if the phase volume of the aqueous phase is well above the critical value. These aggregates contain an aqueous phase encapsulated by the polymer. The kinetics of this phase inversion is studied and the use of the technique to obtain microcapsules from aqueous solutions is investigated.