W.‐D. Hergeth

Polymerization in the presence of seeds. Part IV: Emulsion polymers containing inorganic filler particles

Abstract Polymer composites containing quartz powder filler particles were produced by the emulsion polymerization technique. The distribution of the inorganic material was observed by electron microscopy. Ultrasonic velocity measurements, differential scanning calorimetry (d.s.c.) and nuclear magnetic resonance (n.m.r.) were used to investigate the properties of the polymer composites. Deviations from the properties of the pure polymers can be discussed in terms of a modified polymer shell around the filler particles. The thickness of this shell varies between approximately 2 nm and 9 nm.

Polymerizations in the presence of seeds: 3. Emulsion polymerization of vinyl acetate in the presence of quartz powder☆

Abstract The emulsion polymerization of vinyl acetate in the presence of quartz powder (‘Suprasil’) was investigated. Ultrasonic velocity measurements showed that the concentration of monomers in the vicinity of the particles is very high compared with the concentration in the bulk dispersion medium. Therefore, polymerization in a surface layer around the particles should be enhanced. Electron micrographs of samples extracted during the first step of the polymerization and the dependence of reaction rate on pH value and initiator concentration can be explained in terms of this surface coating process.

Polymerizations in the presence of seeds: 5. Core-shell structure of two-stage emulsion polymers

Abstract Polymeric dispersions with a concentric core-shell structure of the latex particles were obtained by a two-stage emulsion polymerization technique. Conditions for the formation of shells on polymeric seeds are discussed. The process of shell formation was detected by electron microscopy. A small-angle neutron scattering investigation was carried out in order to verify the core-shell structure of the particles.