Abstract Raw materials for nonwoven filter media are divided into four categories: polymers, fibers, resins, and additives. Polymers are the building blocks from which fibers, resins, and many additives are formed. Fibers are sourced from natural and synthetic polymers and also inorganic materials. They are available in nanofiber form. In dry formed and wet laid web operations, fibers are the basic raw material fed into the web forming process. In spun-web processes, polymers are spun into fibers that lay down randomly to form the web. Resins are the glue holds the fibers together and provide various properties to the nonwoven web. Additives add properties to the web such as adsorption, color, flame retardancy, water repellency etc. Membrane filter media are composed of natural, synthetic, and inorganic materials.