Parafilm is a plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 paraffin

Paraffin

In chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the...

 film

Film

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...

 with a paper

Paper

Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 backing produced by Pechiney Plastic Packaging Company, based in Chicago, Illinois primarily used in laboratories. It is commonly used for sealing or protecting vessels (such as flask

Flask

Flask may refer to:* Laboratory flask, laboratory glassware for holding larger volumes than simple test tubes* Vacuum flask a container designed to keep warm drinks warm and refrigerated drinks cold...

s or cuvette

Cuvette

A cuvette is a small tube of circular or square cross section, sealed at one end, made of plastic, glass, or fused quartz and designed to hold samples for spectroscopic experiments. The best cuvettes are as clear as possible, without impurities that might affect a spectroscopic reading...

s). It is ductile, malleable, waterproof, odorless, thermoplastic

Thermoplastic

Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...

, semi-transparent and cohesive.

It is also used to further seal a lidded container against moisture and air contamination for long term storage. However it is also claimed that Parafilm breaks down over time on exposure to air and light

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 and so does not serve as a long-term sealant.

Since it is a thermoplastic

Thermoplastic

Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...

, Parafilm is not safe for use in an autoclave

Autoclave

An autoclave is an instrument used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents. It was invented by Charles Chamberland in 1879, although a precursor known as the...

.

Volatile organic solvents

Volatile organic compound

Volatile organic compounds are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and...

 will dissolve Parafilm.

Parafilm is sometimes used by modelers as a masking material during airbrush

Airbrush

An airbrush is a small, air-operated tool that sprays various media including ink and dye, but most often paint by a process of nebulization. Spray guns developed from the airbrush and are still considered a type of airbrush.-History:...

ing, due to its lack of adhesion

Adhesion

Adhesion is any attraction process between dissimilar molecular species that can potentially bring them in close contact. By contrast, cohesion takes place between similar molecules....

, which can destroy a finish

Finish

Finish refer to:* Finishing in the distillation of Scotch* Finished good, a good that is completed as to manufacturing but not yet sold or distributed to the end-user* Surface finishing, various industrial processes for modifying a workpiece's surface...

.

Horticulturalists sometimes use Parafilm in grafting

Grafting

Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...

. Several grafting styles call for wrapping a graft to hold it together, and sealing it to prevent drying and Parafilm does both. In this context Parafilm is also known as grafting tape.

Entomologists have used Parafilm as a membrane to feed hematophagous insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s such as mosquitoes and bedbugs reared in the lab.