Plastics We can define plastic
In addition, we can add pigments to give color, additives to improve certain benefits.
Before entering the subject, search in youtube some videos on this fears.
A plastic is formed by the union of several molecules (denominated monomers) to give rise to great other but, call polymer.
This is something as well as to construct houses of different size (polymeric) basing us on an essential element, that is the brick (monomer)
In order to arrive at polymer one resorts to the process polymerisation by which, in a process thermal-chemistry they connect monomer to give rise to the long chain of polymer
In order to make a plastic, it is necessary to connect monomers to each other to form polymer. This phenomenon denominates polymerisation reaction.
Search information of how polymerisation in plastics takes place
2 Properties of plastics.
If we consider which weight, we can say that the plastics are very resistant. For this reason and when the weight is fundamental (ships, cars, etc) usually is used next to metallic alloys to reduce the weight and, consequently, to lower the power consumption.
Combustibility. Due to the presence of Carbon and hydrogen in the molecule of the plastic, the majority of plastics burns easily.
Plasticity. A great group of plastics has the capacity to mold when increasing the temperature, without loss of their properties. This allows the manufacture of complicated pieces.
Economy. Except for some types, the plastic is a material very cheap.
The basic characteristics of these is that when increasing the temperature, can be molded, without losing its basic characteristicses. They are possible to be recycle, that is to say, we can take this type from plastic to make other objects of the same.
He is not recyclable by heat.
An example of this family is a tire of a car, made by rubber that it can be natural or synthetic. So that the function of the tire is optimal, in the manufacture it goes through a vulcanization process, that to simplified way consists of adding to sulphur to the mixture and its later heating. In this way we were able to stop of a very flexible and sticky substance, to another one with more interesting properties and a substantial improvement as far as hardness and durability, increase of the resistance to the chemical attack and, all this without losing the natural elasticity of the material.
But this process does not pause, but it continues permanently once the manufacture process has finished. According to the external factors (temperature, light, pressure, etc) the process will follow more or less fast.
In the following image is a tire that, although does not have many kilometers of tread, already presents important signs of crystallization with the presence of important fissures.
Activity. In the previous video we have seen the polymer chains for each group. It represents each for each plastic group.
We will see some examples
|Thermoplastic||Polythene (PARTIDO POPULAR) employee in buckets, bags, insulators for cables.||PVC. Very used for windows or pipes of desague|
PET. Very used for bottles
|Heat-stable||Phenols. Applications in electrical equipments, handles of kitchen utensils, laminate for wood, etc||
Amines: Used in resin and ship's hulls of union for boards plywood, among others.
Polyester resins (UP). Examples of use are the canes to fish, skis, tanks.
|Elastomers||Neoprene. Used in coverings of cables and suits of diving among others||Rubbers, good example of it are the tires of the cars|
Other that are important
The Teflon (PTFE) is a polymer where the monomer (to see the left) is made up of atoms of carbon and atoms fluorine. The chemical formula is CF 2 =CF 2. The virtue main of this material is that he is practically inert, that is to say, that is very rare chemical reactions with other substances which mainly confers the “affection to him of the human” when we must it put as covering in the frying pans. This is due basically to the protection of fluorine atoms in the chain
But, as always it has But, a present by-product in the called teflon acid perfluorooctanoico (PFOA), is polluting (he is not biodegradable), and with serious suspicions of being potentially cancerigenic. There are studies on the relation of the infertility, immune upheavals or problems of prenatal growth and the use of this material.
The frying pans with covering of teflon are losing the layer with time, and we ended up ingesting the teflon
For this reason, in the illustration of the frying pan we have preferred to show one with ceramic covering.Dictionary: Casein
: it is a species of protein (fosfoproteína) present in milk. It is used to make some types of glues and paintings, plastics, covers, packing, etc Cellulose
: The cellulose is a very long chain of a polymer. One is in the wood, with a 50%, although it is the cotton, with a 90% of cellulose, the alive being whom but contained it has. With the cellulose we play the natural role and weaves of fibers. Other applications are the manufacture of explosives, celluloid, varnishes, etc. Rubber
: The rubber is a very elastic polymer, that is obtained from a milky emulsion (latex) in the sap of certain plants, as the Hevea brasiliensis or the tooth of lion. Nowadays they make a great variety of rubber articles, perhaps the most known is the tire, although there are others as and raincoats.