Estimation of morphology of composite polymer emulsion particles by the soap titration method

Abstract

The occupied area (Am) of a sodium dodecyl benzene sulfonate molecule adsorbed on particles was measured by the soap titration method. The Am values are 214, 133, and 53 Å2 for poly(methyl acrylate) (I), poly(methyl methacrylate) (II), and polystyrene (III), respectively. For methyl metharylate‐styrene copolymer emulsions the additivity was established between the Am value and copolymer composition. Composite emulsion particles consisting of I/II, I/III, and II/III were prepared by seeded emulsion polymerization. For these emulsions the relationship between polymer composition at the surface layer calculated from the Am value and that in a particle calculated from the polymerization process was investigated. This relationship is remarkably affected by the order of polymerization, the hydrophilicity of polymer, the flexibility of the seed polymer, and the monomer addition method. The models of the morphology of these composite particles explain the results successfully.

Miniemulsification in high‐pressure homogenizers

“…The stronger adsorption is related to a lower value of the area covered by a molecule of emulsifier (parking area), and it is well known that the parking area decreases with the hydrophobicity of the organic phase. 11 This is confirmed by the results presented in Table 2, which showed that, for a given concentration of emulsifier, the surface tension of the miniemulsion increased with alkyd resin contents even though the total surface area of the droplets decreased. However, the droplet sizes reported were those corresponding to a high number of cycles in the homogenizer, i.e., when no further reduction of the droplet size was observed.…”

Seeded dispersion polymerization

“…To prepare structured latex particles, three main methods of preparation have been considered and studied: First, the functionalization of latexes by copolymerization of a monomer with the addition of small amounts of a second monomer bearing a chemically reactive group such as carboxyl, [1][2][3][4] amide, 5,6 sulfate, 7,8 sulfonate, 9 and hydroxyl; 10,11 second, the copolymerization of comonomers that markedly differ in their water solubility 12,13 or reactivity ratios; 14,15 and third, the polymerization in the presence of a polymer dispersion that is prepared in advance; that is, seeded emulsion polymerization.…”

Supermicron polymer particles with core‐shell type morphologies

“…Studies using PMMA seed particles and styrene as the added monomer have been reported 5,[7][8][9][10] but none of these studies examined partially polymerized host particles, in which monomer from the host polymer remains when the addition of the second monomer commences. The characteristics of our process differ markedly from those used in previous studies.…”