Here's a breakdown of why that results in burning:
* Plastic Composition: Most synthetic hair fibers are made from materials like:
* Polyester: A common and inexpensive plastic.
* Acrylic: Another type of plastic known for its soft texture.
* Polyvinyl Chloride (PVC): Less common in hair, but still a plastic.
* Modacrylic: A modified acrylic that is somewhat more heat-resistant than regular acrylic.
* Breaking Down the Polymers: When heat is applied, the long chains of molecules that make up these plastics begin to vibrate and break apart. This produces smaller, volatile molecules.
* Combustion: These volatile molecules are often flammable. They react with oxygen in the air in a rapid oxidation process – combustion. This releases energy in the form of heat and light, which we perceive as fire.
* Byproducts of Burning: The combustion process produces various byproducts, including:
* Carbon dioxide (CO2): A colorless, odorless gas.
* Water vapor (H2O): Also a colorless, odorless gas.
* Smoke: Particulate matter (unburned carbon particles and other materials) suspended in the air.
* Harmful Chemicals: Depending on the specific type of plastic, burning synthetic hair can release potentially toxic chemicals such as:
* Formaldehyde: A known carcinogen.
* Hydrogen chloride: An irritant gas.
* Dioxins: Highly toxic environmental pollutants.
In summary, synthetic hair burns because it's made of flammable plastic polymers that break down into volatile gases when heated, which then combust in the presence of oxygen.
Important Considerations:
* Different Synthetic Hair Types Burn Differently: Some types of synthetic hair are treated to be more flame-retardant, but they are rarely, if ever, completely fireproof. Modacrylic, for example, is often used because it has some resistance to ignition. However, if exposed to enough heat for long enough, it *will* still burn.
* Burning Plastic is Dangerous: The smoke and fumes produced by burning synthetic hair can be harmful to breathe. It's crucial to be careful around open flames and heat styling tools when wearing synthetic hair and to avoid burning it intentionally.
* Real Hair Burns Too: While real human hair is more resistant to burning than synthetic hair, it will also burn under enough heat. It's made of keratin, a protein, which is also combustible, although it tends to char and singe rather than burst into flame as easily.