Submicron Sized Hollow Polymer Particles: Preparation and Properties

Abstract

The considered method for obtaining hollow polymer particles is based on the following pathway: (1) preparation of a carboxylated core latex by emulsion copolymerization of acrylic monomers with methacrylic acid, (2) synthesis of a core‐shell latex comprising a styrene (co)polymer shell, (3) neutralization of the core carboxylic groups with a base followed by the core ionization and hydration to a high degree, shell expansion and formation of water‐filled hollows. A number of approaches to improve the hydrophilic core – hydrophobic shell compatibility and enlarge the hollow volume are considered. The synthesized hollow particles are of a submicron size with the relative hollow volume Vhol : Vpart.= 0.43 – 0.64. Methods for cationic hollow particle latex preparation by anionic latex recharging with a cationic surfactant or acidic melamine resin are discussed. Recharging with a melamine resin is shown to afford hollow particles with an external polymer shell providing a high thermal stability of the particles.

Aqueous Polymeric Hollow Particles as an Opacifier by Emulsion Polymerization Using Macro-RAFT Amphiphiles

“…Water removal during the drying process creates hollow structures of strong rigid polymer shells wrapping around air voids . The most common method to synthesize single void polymeric hollow particles is by seeded emulsion polymerizations in which swellable latex particles are coated with stretchable cross-linked polymer shells. ,− This approach was first pioneered by researchers at Rohm and Haas Co., whom have successfully developed commercially available ROPAQUE polymeric hollow particles with monodisperse particle size distributions and well-controlled shell thickness to replace titanium dioxide pigments in paints. , However, this method consists of many complicated multiple steps and harsh swelling conditions of strong basic solution at elevated temperatures . Furthermore, the final latexes also contained free surfactants, which might be undesirable for some applications.…”

New Possibilities for Controlling the Morphology of Core-Shell Latex Particles During Emulsion Polymerization

“…The initial composition of the monomers in tank 2 precisely corresponded to the composition of the core copolymer. When constructing the plots, we calculated the shell radius r s in various stages of the process by the equation (16) r s = r c + ÄÄÄÄ . Table 1.…”

Adsorption and emulsification properties of amphiphilic poly(styrene-co-octadecyl maleamic acid salt) with comb-like architecture

“…OSEP2 exhibited hollow structures in contrast to PSSDS and OSEP1 that showed rigid structures. From the literature, it could be seen that various methodologies are adopted to generate hollow PS particles, wherein most of them are related to hollow spheres of size >100 nm [46][47][48][49], except a few reports on size much less than 100 nm [50]. The approaches basically include emulsion or suspension polymerization reactions or both employing different surfaceactive materials chosen from simple surfactants and even glass membrane.…”