High PVC film‐forming composite latex particles via miniemulsification, part 2: Efficiency of encapsulation

Abstract

ABSTRACT:The application of a density gradient column (DGC) method using sodium polytungstate (SPT) solutions as the medium was investigated for determining the encapsulation efficiency of 11-30% pigment volume concentration (PVC)) latex particles prepared by the miniemulsification process. The encapsulation efficiencies for 11, 20, and 30% PVCs were found to be 100% of the TiO 2 encapsulated inside 86.3, 98, and 98.9% of the styrene/n-butyl acrylate copolymer, respectively. The copolymer not participating in the encapsulation (free copolymer) was found in the 1.04 g/mL density layer of the DGC. Particle size analysis by DLS (dynamic light scattering) showed that the encapsulated particle size increased with increasing density. Thus, the number of TiO 2 particles (primary particles) inside each encapsulated particle increased to accommodate both the increased size and density. The results obtained by DLS for each DGC layer of the 30% PVC system were confirmed qualitatively by TEM in terms of the increasing encapsulated particle size and broadening of the size distribution as the density increased in the DGC.

Nanocapsules by Miniemulsion Polymerization with Biodegradable Surfactant and Hydrophobe

“…Several techniques have been devised for the synthesis of polymeric NCs, such as layer‐by‐layer self‐assembly,1, 8 block‐copolymer assembly,9 solvent evaporation,10, 11 and miniemulsion polymerization 12. Miniemulsion polymerization is a versatile and efficient technique for the formation of NCs as it can be achieved in a single step,13 with high encapsulation efficiency,14, 15 and liquid12, 13, 16–19 or solid15, 20–22 cores can be obtained. During miniemulsion polymerization, NCs are formed by initially dispersing droplets of monomer and hydrophobe (to be encapsulated) in water using a suitable interfacially active species, and with the help of high shear.…”