We explain what polymers are, their classification, properties and characteristics. In addition, natural and synthetic polymers.
What is a polymer?
In chemistry, polymers are a type of macromolecules consisting of chains of simpler units, called monomers, linked together by covalent bonds (Van der Waals forces, hydrogen bonds or hydrophobic interactions). Its name, in fact, comes from the Greek polys ( muchos ) and mere ( segmento ).
They are generally organic molecules of enormous importance both in the natural and industrial world of the human being. These include the DNA in our cells or the starch of the plants, up to the nylon and most of the plastics.
In the late nineteenth and early twentieth centuries it was discovered how to manipulate them . This is how revolutionized forever the handling of materials by mankind.
If they are classified according to their origin, the polymers can be:
- N atural polymers . Its origin is biological.
- Intimate polymers . They are created entirely by the human being.
- Emitynthetic polymers . They are created by transformation of natural polymers.
If they are classified according to their composition, we can distinguish between:
- Polymers or rgnicos, which have a main chain of carbon atoms.
- Vinyl polymeric or polymeric, similar to organic, but with carbon-carbon double bonds. They include polyolefins, styrenics, halogenated vinyl and acrylics.
- Non- vinyl polymeric or polymers, they have atoms of oxygen and / or nitrogen in their main chain, in addition to carbons. They include polyesters, polyamides and polyurethanes.
- Polymers and norgénicos, based on other elements such as sulfur (polysulfides) or silicon (silicone).
It can serve you: Organic matter, Inorganic matter
Natural polymers exist as such in nature, as biomolecules and compounds that make up the body of living beings. The appearance of natural polymers in the world represented an important point in the biochemical complexity of life.
These include the vast majority of proteins, nucleic acids, polysaccharides (complex sugars, such as plant cellulose and fungal chitin), rubber or vegetable rubber, and a huge etcetera.
The first synthetic polymer was created in 1907: bakelite, durable and inexpensive material. Its great industrial success was largely due to its simple and economical manufacturing, using phenol and formaldehyde. Much progress has been made since then in obtaining new and more powerful materials of organic origin, particularly in the petrochemical industry.
The polymers can be created in the laboratory by joining specific monomers in a chain, using organic or inorganic inputs, under controlled conditions of temperature, pressure and presence of catalysts. This generates a chain or step reaction that results in the generation of the compound.
Properties and characteristics of polymers
In general, polymers are bad electrical conductors, so they are often used as insulators in the electrical industry, for example, plastic as a cable wrap. However, there are conductive polymers, created in 1974, whose applications are still being studied.
Temperature, on the other hand, is an important factor in the behavior of polymers. At low temperatures they become hard, fragile, similar to glass, while at normal temperatures they tend to elasticity. If the temperature rises to its melting point, they begin to lose their shape and decompose.
More in: Properties of matter
Examples of polymers
Some of the most known and most important human polymers are:
- Polyvinylchloride Also known as PVC and of general formula (C 2 H 3 Cl) n, it is obtained from the polymerization of vinyl chloride units. It is the derivative of the most versatile plastic that is known and used for all types of packaging, footwear, coatings, flexible and even pipes.
- Polystyrene Known as PS, it is obtained from styrene monomers, being able to obtain very different results: more or less transparent, more or less brittle, or even very dense and waterproof variants. It was first synthesized in Germany in 1930 and since then about 10.6 million tons are produced annually in the world.
- Polymethylmethacrylate Abbreviated with the acronym PMMA, it is a typical engineering plastic, and is one of the most competitive in terms of its industrial applications, being extremely transparent and resistant.
- Polypropylene Referred to as an acronym PP, it is a thermoplastic polymer, partially crystalline and made from propylene or propene. It is used in food packaging, tissues, laboratory equipment and transparent films or films to coat.
- Polyurethane . This polymer is obtained by combining hydroxyl bases and diisocyanates, and they can be thermoplastic or thermostable. They are frequently used in the footwear, paint, synthetic textile fibers, packaging, preservatives or machine and vehicle components industry.
Follow with: Polyethylene