¿Qué son los POLÍMEROS y cuáles son sus propiedades? (Ejemplos de polímeros)

Hi how are you? Today I will explain to you what polymers are, their properties, the types that exist and I will give you several examples. A polymer is a substance made up of very large molecules called macromolecules, which are made up of many small, repeating units that are chemically linked one after another.

The word polymer comes from the Greek and literally means “many parts”. Each of these “parts” that make up the polymer is called a monomer (a part). For this reason, we can think of a polymer as a molecule made up of many monomers linked together like little legos or building blocks.

The monomers that form a polymer can be of different types and can also be all the same or a combination of different monomers. This results in the existence of several different types of polymers, as we will see later. Today, we live surrounded by all kinds of polymers.

All plastics, from those that make up grocery bags to the acrylic panels in a fish tank, are polymers. Proteins, flours and most of the carbohydrates we eat are too. Even the DNA molecule that contains all of our genetic information is a polymer.

Properties of polymers Polymers can be made with very different properties, but even so, there are some properties that are common to most of them: They generally form amorphous solids rather than crystalline solids. Most are thermoplastic, which means they can be molded like clay at high temperatures. Some are elastic while others are very stiff.

Some, like nylon, are very tensile. They are almost always inert or not very reactive, so they can last a long time without decomposing. Most synthetic polymers are not biodegradable.

Some are recyclable. Some are transparent like glass (or more, even) while others are completely opaque. Most are insulators, that is, they are very poor electrical conductors.

Most are poor thermal conductors. Types of polymers Polymers can be classified according to different criteria: According to their origin: Synthetic: are those that are produced artificially in chemical plants such as plastics. Natural or biopolymers: are those produced by living beings such as proteins and nucleic acids.

Semi-synthetic: are those produced by transformation or modification of natural polymers. According to the monomers used Homopolymers: are those formed by a single type of monomer. All subunits are equal to each other, such as polyethylene which is made only of ethylene molecules linked together.

Copolymers: They consist of polymers of 2 different monomers. These can be distributed in the chain randomly, alternating or in blocks of each monomer. Heteropolymers: are those formed by more than two different monomers.

Proteins are an example of polymers made up of 21 different monomers, which are amino acids. According to their physical properties Thermoplastics: are those that can be heated until they melt and cool again while maintaining their properties. Thermosetting: they are those that, when heated, are transformed into harder and more resistant polymers by the formation of new links between the chains.

Bakelite is a good example of this class of polymer. Elastomers: are elastic polymers such as rubber. According to its structure Linear: linear polymers consist of long chains of monomers linked one after another without the appearance of branches.

Branched: Contrary to linear, these polymers have long central chains, but they also have other shorter side chains that form branches. Cross-linked: These polymers consist of linear or branched polymers in which the main chains are linked to each other through other shorter chains. Crosslinked: Instead of monomer chains, crosslinked polymers consist of extensive two- or three-dimensional networks as in the case of graphite, diamond, and concrete.

Depending on the type of bond between the polyolefin monomers: they are formed by the union of unsaturated hydrocarbons such as ethylene. Polyesters: are those in which the monomers are linked by condensation between an acid and an alcohol. Polyethers: in these cases the monomers are linked through an oxygen atom.

Polyamides: monomers are linked by condensation between an acid and an amine. Cellulose polymers: they consist of modified biopolymers in which sugar monomers are linked by means of a glycosidic bond. Acrylic polymers: they are a family of polymers derived from acrylic acid and its esters.

Vinyl polymers: they are similar to polyolefins but with substituents such as chlorine or fluorine. Polyurethanes: are polymers derived from isocyanates. Examples of polymers 1.

Polyethylene (PE) It is by far the most produced and used polymer in the world. They consist of a linear polymer made up of ethylene units one after the other. It is the plastic used in the manufacture of balls.

2. Polyethylene glycol (PEG) It is a homopolymer that belongs to the family of polyethers. This polymer is used as a laxative, as a base for making creams and as skin lubricants.

3. The DNA molecule Deoxyribonucleic acid is a biopolymer made up of four monomers called nucleotides, which are thymine, guanine, cytosine and adenine. It contains all the genetic information encoded in the form of the sequence of said nucleotides.

4. RNA This biopolymer is similar to DNA with the difference that the nucleotides contain ribose instead of deoxyribose. They participate in the transcription and translation of the genetic code.

5. Bakelite It was the first synthetic polymer that existed. It is a very hard and temperature resistant material that is used for knife handles and many other applications.

6. Starch Another biopolymer, but in this case the monomers are glucose molecules, which is a sugar. Plants produce them to store energy.

7. Teflon (PTFE) Teflon is the trade name for polytetrafluoroethylene or PTFE. It is found on the nonstick surfaces of many pots and pans, as well as in pipe joints to make the joint airtight.

8. Cellulose It is the most abundant biopolymer (and polymer) on earth. It forms part of the cell walls of all plant cells and is an almost inexhaustible source of raw material for the synthesis of biodegradable semi-synthetic polymers.

9. Proteins They are heteropolymers made up of 21 different monomers. They are also biopolymers, since they come from living beings.

10. Polystyrene (PS) Polystyrene is an aromatic polymer that is widely used to produce elastic foams. 11.

Polyvinyl chloride (PVC) This thermoplastic is known throughout the world for its use in water pipes. 12.