Most manufactured polymers are thermoplastic, meaning they can be repeatedly heated and shaped after production. This characteristic of the polymer allows easy machining and deformation and recycling. Thermostats cannot be re-melted. If the polymer is reheated after production, the material degrades but never melts.
Each polymer has very different properties, but most polymers have the following common characteristics:
Common properties of polymers:
1- Polymers have high resistance to chemicals. Consider cleaning liquids packaged in plastic in your home. On the parts of the label, the dangers that the chemical causes when it comes into contact with the skin or eyes or if it is swallowed are written. The extent of this risk highlights the chemical resistance of that polymer. Some plastics dissolve easily, while others may require more aggressive solvents
2- Polymers can be both thermal insulation and electrical insulation. Consider all electrical appliances, cords, outlets, and wires made or coated with polymeric materials. Polymer pot and pot handles, coffee pot handles, refrigerator and freezer foam cores, insulated cups, coolers, and microwave pots are produced with polymer for heat resistance. The thermal underwear that many skiers wear is made of polypropylene, and the fiberfill in winter jackets is acrylic and polyester.
3- Polymers are very light and very strong. So the polymer has many uses, including toys, the bone structure of space stations, fine nylon fibers in tights, and Kevlar in bulletproof vests. Some polymers float in water and others sink. However, compared to the density of stone, concrete, steel, copper or aluminum, it can be said that all plastics are light.
4- Polymers can be processed in different ways. Fine fibers, heavy tubes, films or food bottles are produced by extrusion. Very complex parts or large car body panels can be produced by injection molding. Adhesives and paints are produced when plastics are molded into barrels or mixed with solvents. Elastomers and some plastics are quite flexible. Some plastics, such as soda bottles, are stretched during processing to maintain their shape. Polymers such as polystyrene (styrofoam), polyurethane and polyethylene can be converted into plastic foam.
5- Polymers are materials that have an unlimited range of properties and colors. Polymers have many inherent properties that can be improved with a wide variety of additives to expand their applications. Cotton, silk and wool fibers can be imitated with polymers. Similarly, porcelain can be made to look like marble, aluminum and zinc. Polymers are also used to produce products that are not readily available in nature, such as plastics and flexible foams
6- Polymers are not always made from oil. Many polymers are made from natural gas, coal, or crude oil. However, as their building blocks, they are sometimes composed of renewable materials such as polylactic acid from corn or cotton cellulosics. Plastics such as screwdriver handles or gift ribbons are always made from renewable materials such as cellulose acetate.
7- Products that cannot be produced with other materials can be made with polymers. Polymers can be made into transparent and waterproof films. Medical tubes and blood bags are produced with PVC, thereby increasing the shelf life of blood and blood products. Thanks to PVC, flammable oxygen can be transported in non-flammable flexible pipes. Antithrombogenic agents such as heparin are combined with a flexible PVC catheter used in open heart surgery, dialysis, and blood collection. Effective operation of many medical devices is possible with polymers.