Preparation of a Water Soluble Acrylic Copolymer

In this example, the emulsion polymerisation technique is used to prepare a high molecular weight acrylic copolymer in latex form. The latex is then destabilised and the pendant acid groups on the acrylic polymer backbone are used to solubilise the polymer in water. Care must be taken during the latex destabilisation process to avoid the formation of water insoluble particles. 

Prepare a pre-emulsion by adding a solution of stabilising colloid in water to a mixture of the acrylic monomers and surfactant. 

Add the pre-emulsion to the reactor over 2 hours at 80°C. Then hold a further 2 hours at 80-85°C after completion of the pre-emulsion addition. 

Add 30 parts of water to 100 parts of acrylic latex in the reaction vessel. 

Adjust the pH to above 7.5 with tri-methylamine stirring the mixture during the pH adjustment. 

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The alternative route of preparing water reducible resins using emulsion polymerisation of an acid functional acrylic resin has already been considered under emulsion example 7 - preparation of a water soluble acrylic copolymer. 

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