The different types of polymeric materials include substances like plastics and elastomers. Polymeric materials can be made into biodegradable foam, renewable plastics, and even edible films and coatings. There are also shape memory polymers (SMPs) and ferroelectric polymers. Some polymeric materials were developed for use in automobile fenders, clothing, and medical applications. Polymers show up in everyday items like milk jugs, tires, medical equipment, and edible coatings.
Memory or shape memory polymeric materials are capable of being transformed from a rigid and hard plastic to an elastic polymer and back, over and over, without material degradation. When heat is applied and the polymer rises to a specific transition temperature, the material goes from hard to flexible and then back again when the polymer cools. Changes in the shape may also be induced by an electric current, magnetic field, and even light. The most familiar type of SMPs in use today are found in helmets and in the insulating foams which expand when temperatures become warmer, increasing a window's insulating efficiency. Some SMPs are biodegradable and are being developed for use as vascular stents, drug delivery systems, surgical sutures, and in tissue regeneration.
Ferroelectric polymers have the unique ability to transfer heat when exposed to an electric field. These polymeric materials have a disorganized molecular structure with randomly-placed molecules. When electricity is applied, this random structure becomes organized and the polymer gives off heat, becoming colder. When the current is discontinued, the polymeric materials absorb heat. This new material could eliminate the compressors, coils, and toxic gasses used in refrigerators and air conditioning units and might also be used in protective gear for firefighters, to warm a child's mittens, and in circuit boards to cool components.
Polymeric materials are produced from raw materials or from post-consumer recycled content, although the process required to reclaim and recycle polymeric materials may not be as cost effective as glass and metal recycling. All plastics are considered polymers, but not all polymers are considered plastic. Thermoplastic polymers may be heated and formed again and again, making them the perfect type of recyclable material. Thermoset polymers, however, change their molecular structure when heated and cannot be re-formed which makes them very difficult to recycle and re-use.