Plastic

A **plastic** is a material that can change its shape easily. Many things are made of plastics, usually because making them to the right shape is easy.   

Some plastics have other materials added to them, like glass, because they make the plastic stronger and stiffer.  

Plastics are used to make many products, including nylon or polyester clothing; toys; electronics; food containers; pipes; bags; parachutes; ropes; car parts; medical supplies; bulletproof glass; and body armor.  

## Types 
There are many types of plastic. Some can be shaped only when they are freshly made; then they become hard.  Others are thermoplastic and can be softened by heating them. These plastics can be used for 3D printing, because the plastic will become soft enough to form into different shapes, and then become hard again when they cool down.  

## History 
For many years, people experimented with plastics based on natural polymers like cellulose. In 1855 Alexander Parkes (1813-1890), an English inventor, created an early form of plastic called "Parkesine." It was hard but flexible and transparent. 

In 1869 John Wesley Hyatt invented the first synthetic (man-made) polymer as a substitute for ivory. Billiards were becoming popular, and billiard balls were made of ivory. Natural ivory is obtained by slaughtering wild elephants, and there were not enough elephants to meet the demand for ivory.  These plastics are called bioplastics.  Some are biodegradable. 

## Pollution & recycling 
 container on a Malaga beach]]
Old plastics are usually thrown away and put in landfills. Because plastic lasts so long, plastic pollution is a major problem. The Great Pacific Garbage Patch and other marine trash vortexes are made mostly of microplastics. 

Some plastics can be recycled so they won't become waste. However, recycling plastic requires heating, and some plastics release toxic fumes when heated. Some activist organizations argue that recycling is not a solution for plastic pollution. 

According to activist Judith Enck: *When it comes to plastics, recycling has been an abysmal failure, and only 5% to 6% of plastics actually gets recycled in the United States ... The plastics industry has spent millions of dollars lying to the public and letting people think that plastics are recyclable when over 90% of them are not and they know that better than anyone.* 

## Well-known plastics 
 stockings under a microscope]]
There are many well-known plastics:
* Polyamide (usually called nylon) is used in women's stockings, parachutes, ropes, gears, car parts, and toothbrush bristles.
* Polycarbonate is used in bulletproof glass, compact discs, and DVDs.
* Polyethylene is used to make tubes, bottles, shopping bags, milk jugs, and body armor (made with polyethylene with especially long chains).
* Polyethylene terephtalate is called PET when used for bottles, and polyester when used for clothes or other materials.
* Polypropylene is used to make food containers and chairs.
* Polystyrene is used for CD cases, plastic cups, plastic forks and knives, packaging foam, and insulation.
* Polyurethane is used in rubber, foam, and shiny coatings on wood and tile.
* Polyvinyl chloride (usually called PVC) is a common material for pipes; chemicals can make PVC softer for toys and cushions.
* Polylactic acid (PLA) is used in 3D printing.
* Cellulose acetate is used for photographic film and cigarette filters.
* Acrylonitrile butadiene styrene (ABS) is used to make electronics, toys, and car parts.

## References