1. Filters:
Cigarette filters are specifically designed to absorb vapors and to accumulate particulate smoke components. Filters also prevent tobacco from entering a smoker's mouth and provide a mouthpiece that will not collapse as the cigarette is smoked. Filters generally have the following components:
A "plug" of acetate cellulose filter tow
95% of cigarette filters are made of cellulose acetate (a plastic), and the balance are made from papers and rayon. The cellulose acetate tow fibers are thinner than sewing thread, white, and packed tightly together to create a filter; they can look like cotton. Other materials have been tried and rejected in favor of the taste that acetate produces. Filters vary in filtration efficiency, depending on whether the cigarette is to be "light" or regular.
How many fibers are in a cigarette filter?
The following is quoted from a research paper by researchers from the New York State Department of Health, the Roswell Park Cancer Institute, and Cornell University. Click here for full article.
"Viewing the white face of the cigarette filter with the naked eye and compression of the filter column with the fingers would suggest that the filter is made of a sponge-like material. However, opening the cigarette filter, by cutting it lengthwise with a razor, reveals that it consists of a fibrous mass. Spreading apart the matrix reveals some of the more than 12 000 white fibers. Microscopically, these fibers are Y shaped and contain the delustrant titanium dioxide. The fibers are made of cellulose acetate, a synthetic plastic-like substance used commonly for photographic films. A plasticiser, triacetin (glycerol triacetate), is applied to bond the fibers."
An inner paper wrapper (plug wrap) and glue
The paper used to wrap the acetate cellulose plug is impervious to air for regular cigarettes, or is ventilated and very porous in "light" cigarettes, allowing more air to enter the smoke mix. A polyvinyl acetate emulsion is used as the glue to attach the plug to the wrapper, and to seam the wrapper.
http://www.longwood.edu/cleanva/cigbuttfilters.htm