Polymerization techniques Homogeneous systems Bulk polymerization Solution polymerization Heterogeneous systems Suspension polymerization Emulsion polymerization Precipitation polymerization Polymerization in solid state Polymerization in the gas phase

Bulk polymerization Advantages Disadvantages Applications Polymerization of the undiluted monomer. Viscosity increases dramatically during conversion. Heat removal and hot spots Advantages Disadvantages * Pure products * heat control * Simple equipment * dangerous * No organic solvents * molecular weights very disperse Applications Polymers through step reactions (nylon 6) PMMA-plates

Solution polymerization Monomer dissolved in solvent, formed polymer stays dissolved. Depending on concentration of monomer the solution does not increase in viscosity. Advantages Disadvantages * Product sometimes * Contamination directly usable with solvent * Controlled heat * Chain transfer to release solvent * Recycling solvent Applications Acrylic coating, fibrespinning, film casting

Suspension polymerization Water insoluble monomers are dispersed in water. Initiator dissolved in monomer. Stabilization of droplets/polymer particles with non-micelle forming emulsifiers like polyvinylalcohol or Na-carboxymethylcellulose. Equivalent to bulk polymerization, small droplets dispersed in water. Product can easily be separated, particles 0.01-1mm. Pore sizes can be controlled by adding a combination of solvent (swelling agent) and non-solvent. Viscosity does not change much. Qualitative description of emulsion polymerization kinetics

Suspension Polymerization Advantages Disadvantages * Heat control simple * Contamination with * Product directly stabilizing agent usable * Coagulation possible * Easy handling Applications Ion-exchange resins, polystyrene foam, PVC Qualitative description of emulsion polymerization kinetics

Emulsion Polymerization A micelle forming emulsifier is used. Initiator is water soluble. The formed latex particles are much smaller than suspension particles (0.05-2 µm). Kinetics differ considerable from other techniques. Polymer is formed within the micelles and not in the monomer droplets.

Qualitative description of emulsion polymerization kinetics Antonio de Herrera Tordesillas described an application of natural latex in 1601. A ball game as part of a religious rite.

Emulsion Polymerization Advantages Disadvantages * Low viscosity even * Contamination of at high solid contents products with additives * Independent control * More complicated of rate and in case of water molecular-weight soluble monomers * Direct application of complete reactor contents

Applications of latices Paints-Construction Glues-Adhesives * Paints / rough casting / heat insulation * Wood glues / adhesives for furniture laminates * Elastomeric coatings / primers * Additives for cement and concrete * Adhesives for floor-, wall- and ceiling materials * Anti corrosives / wood coatings * Industrial coatings * Packaging- and lamination glues * Rheology modifiers * Adhesion- and contact glues * Roof coatings * Leather fibres * Fillers and levelling powders * Glues in powder form * Varnishes * Structural Adhesives * Contact Adhesives Paper Textiles * Binders for rubbed paper * Carpet backside coatings * Fleece binder * Boxes and wallpaper * Spunbond / textile coating * Equipment of technical textiles Other * Pressure binder /flocculating glue * Teflon * Elastomers Source: Clariant

Nanotubes for conductive coatings Armoured latex particle Encapsulated pigment Encapsulated clay platelet