Solvents

Solvents are a heterogeneous group of structurally diverse chemicals that can be used to dilute, dissolve, or disperse other compounds. The ability of a solvent to dissolve another molecule is dependent on molecular structure and physical properties of both the solvent and the solute. Solvents can be categorized as organic or inorganic, and in terms of chemical polarity. Polar solvents include water, alcohols, and other –OH containing chemicals, such as acetic acid, that have the ability to donate a H+ and form hydrogen bonds. Polar solvents lacking an –OH group, including acetonitrile, dimethylformamide, and dimethylsulfoxide are protophilic solvents, and are used to dissolve less polar solutes.

Epoxy Resins

Epoxy Resins are used in applications where superior strength, durability, and chemical resistance are needed. Epoxy Resin is more expensive than Polyester Resin and Vinylester Resins so the benefits should be considered before starting your project. Epoxies are available in different viscosities, low viscosity epoxies are used in RTM (Resin Transfer) applications. Epoxy resin cannot be thinned down to lower the viscosity with thinners as this will attack the chemical mechanisms that harden the epoxy, most manufacturers advise warming the resin carefully, bearing in mind also this will speed up the cure time.

Pigments

Pigments are finely ground natural or synthetic, insoluble particles used to impart color when added to paints and coatings formulations. They are also used to impart bulk or a desired physical and chemical property to the wet or dry film. Some of the main pigment classes include:

• - Organic pigments
• - Inorganic pigments
• - Functional pigments
• - Special effect pigments

While organic pigments do not disperse easily and form agglomerates (clumps of pigment particles), inorganic pigments get more easily dispersed in the resin. Functional fillers impart a desired property to the coating like corrosion inhibitor and special effect pigments create optical effects like metallic, hammer finish and diverse color perceptions depending on the angle.