User:Elymco/sandbox/Chlorinated Polyethylene

Chlorinated Polyethylene (CPE) is a polymer that is produced when polyethylene (PE) goes through the process of chlorination which results in the replacement of hydrogen molecules with chlorine molecules. In its natural state, CPE is a white powder-like substance however the chlorine content of CPE can alter its physical properties. Most commonly CPE is used with a chlorine content ranging from 25-48% where it's a rubber however it can also exist as a plastic at low chlorine content and as resin-like substance at higher chlorine contents. The atomic structure of CPE gives it various resistances which makes it a popular modifier (a material that changes the properties of another material).

Properties

Many of the resistances that CPE has come as a direct result of its chemical structure. The arrangement of carbon and hydrogen atoms in a straight line creates a highly stable “spine” which makes any changes to the molecular structure of CPE difficult to achieve. This “spine” is known as a saturated backbone chain and is what results in CPE’s high resistance to extreme temperatures. The working temperature range (also known as the lowest and highest temperatures that a material can reach before it goes through irreversible physical changes) of CPE is -40°C to 150°C. Other resistances resulting from the saturated backbone chain include corrosion resistance from acidic chemicals, weathering resistance (resistance from rain or strong winds), ozone resistance, and moderate levels of inflammability. An important factor about CPE is that it's a non-toxic material, meaning that contact with the skin for prolonged periods of time results in no irritation and only presents mild irritation when coming into contact with the eye.

Applications

The many resistances that CPE has makes it an incredibly versatile material with a wide range of applications

CPE as a modifier

The most common use for CPE is as a modifier for polyvinyl chloride (PVC) materials. Since PVC is naturally very brittle, blending it with CPE greatly increases its impact resistance allowing materials that are made out of PVC to be put under greater stress without compromising its structure. In PVC piping the added ozone and temperature resistances makes the flow of liquids and sewage through these pipes much more stable by decreasing the rate of degradation so that there aren't any leaks or breaks in the piping systems. An added benefit to using CPE as a modifier in PVC is that it greatly reduces the cost of production. When making PVC there is often a material mixed in with the PVC that allows the cost to go down while still maintaining the durability of the PVC. These materials are known as fillers. CPE is often used as a filler in PVC mixtures because of its low cost and its impact strength which results in the production of a PVC mixture that is not only less expensive, but also more resistant to external forces.

CPE plastic

In its plastic form CPE is used as a material in plastic packaging. CPE plastic is often incorporated into food packaging due to its ozone resistance which helps maintain the product inside fresh. Electronics companies also use CPE plastic bags in order to ship delicate pieces of technology since CPE's impact resistance helps protect against scratches and minor punctures. Similarly, CPE plastic is used in disposable protective gowns. These gowns are often used in hospitals due to the material's resistance to common liquids such as blood and water as well as acting as a protective layer against viruses and germs.

Cable jacket

A common trait among wire insulators is the ability to withstand high temperatures and since CPE has a high working temperature range, it is commonly used as an insulator. CPE also has the benefit of having a moderate degree of flame retardancy which gives it an added safety precaution in the case of unintentional sparking. CPE cable jackets also see use in industrial and chemical plants due to the resistances to chemical corrosion.

References

External links

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