![]() Styrene-acrylic emulsion polymers are another good option for exterior applications. As a result, acrylic emulsions are good candidates for binders that must demonstrate excellent exterior durability and UV resistance. This occurs as ultraviolet radiation, absorbed by the polymer, creates destructive free radicals, leading to issues ranging from loss of strength and flexibility to fading color and cracking.Īcrylic latexes made, for example, from methyl methacrylate and butyl acrylate monomers show better UV resistance than those made from styrene and butadiene. ![]() If the end-use application demands that the latex binder be exposed to sunlight, then the material runs the risk of degradation. The first decision confronting chemists is the choice of monomer, which comes down to understanding the environmental conditions of the final product. While the basic polymerization process is the same for any latex, each of the ingredients described above becomes a component that can be chosen by chemists to achieve a specific result. Finally, carboxylic acids and other specialty monomers, which are polymerized into the polymer backbone but exposed at the particle/water interface, help to stabilize the latex. Next, initiator chemicals enter micelles and trigger the chain-reaction polymerization that joins one monomer to another, until a long chain is formed. ![]() Monomers then migrate from larger monomer droplets into the micelles, where they are shielded from water. Most monomers, however, don’t like being in water, so surfactants are added to create cell-like environments - known as micelles - that form when hydrophobic (water-hating) tails of the surfactant gather toward the center while hydrophilic (water-loving) heads orient themselves outward, in contact with the water. Monomers are the building blocks of the polymer.
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