Phenolic, << fih NOH lihk or fih NOL ihk, >> is any of a group of strong and inexpensive plastics materials. Phenolics are resistant to heat and to most solvents. They are excellent electrical insulators. Among the products made of phenolics are light switches, gears, and saucepan handles.
Phenolics are synthetic polymers. A polymer is a long, chainlike molecule. The “links” of the chains are repeating patterns of simple groups of atoms known as monomers. Phenolics are thermosetting plastics–that is, once the plastic has been formed, it cannot be reshaped by heat, pressure, or other physical means (see Plastics (Types of plastics) ). Because of these properties, phenolics cannot be recycled.
Manufacturers use several different methods to produce phenolics. In the most common method, one of a group of organic compounds called phenols is mixed with formaldehyde in the presence of a catalyst. A catalyst is a substance that speeds up a chemical reaction without being used up by the reaction. The mixture is slowly heated, causing the molecules of formaldehyde to form chemical bridges between the benzene rings (ringlike structures of six carbon atoms) in the phenol molecules.
Manufacturers frequently add fillers or additives to phenolics to change their properties to suit various applications. Most phenolic products are shaped, using heat and pressure, in a process called compression molding. In addition, porous materials may be saturated with phenol and formaldehyde, allowing a phenolic to form within the structure of the material. This process is performed with wood to produce Formica-brand tabletops and other work surfaces. A similar process combines phenolic with certain mineral fibers or synthetic fibers to make brake linings for automobiles.
Phenolics are among the oldest plastics. The Belgian-born American chemist Leo Hendrik Baekeland developed the first phenolic in 1907. He patented it in 1909 as Bakelite.
