Polymers and materials made from them, household items, equipment are an important part of industry and human life in general. Natural resources, unfortunately, have been greatly depleted during their use. Therefore, people had to learn how to synthesize artificial materials that have a number of important technical characteristics. One of these is polypropylene. The chemical formula of this compound, the features of its properties and the structure of the molecule will be discussed in the course of the article.
Polymers - general characteristics
This class of compounds includes those that have a very high molecular weight. After all, polymers are complex organic compounds consisting of repeatedly repeating monomer units, which can be from several tens to hundreds, thousands and millions.
Among all polymers, the following groups can be distinguished:
- Natural origin - proteins, nucleic acids, ATP molecules and sonext.
- Artificial - those that are created on the basis of natural ones, but have been chemically modified in order to improve technical characteristics. For example, artificial rubbers.
- Synthetic - those that are created only by chemical reactions, synthesis in the laboratory and industrial plants. Examples here are synthetic fabrics and fibers, polyethylenes, synthetic rubbers, polyvinyl chloride, polypropylene and others.
All designated groups of polymers are important industrial raw materials for the production and production of various equipment, household items, dishes, toys, furniture and other things.
Representatives of the most important synthetic polymers
The chemical formula of one of the most important representatives of synthetic polymers is written as (-CH2-CH2-). This is polyethylene. Areas of its use are known. These are household needs (household film), and industrial, and food industry (packaging material). However, although it is the most common, it is far from the only representative that is extremely important for a person. You can also name polymers such as:
- polyvinyl chloride;
- polypropylene;
- polyisobutylene;
- polystyrene;
- teflon;
- polyvinyl acetate and others.
It is in the construction business, as well as for the manufacture of dishes, that material such as polypropylene plays an important role. Therefore, we will further consider its features from a chemical point of view.
Polypropylene formula
From the point of view of the science of chemistry, the composition of a given substance can be expressed by different kinds of formulas. The first option is the molecular form of the notation. In this case, the polypropylene formula looks like this: (С3Н6) . The last n means the degree of polymerization, that is, the number of structural initial units in the macrochain.
This record allows us to draw a conclusion about the qualitative and quantitative composition of the molecule. Polypropene consists of carbon and hydrogen atoms, and their number in the monomer link is 3/6, respectively, and in the common chain it depends on the n index. If we talk about the very structure of the compound, about the order of the bonds of atoms in the molecule, then another type of recording of the substance is needed.
Polypropylene: structural formula
The type of record, which shows the order of connection of atoms in a molecule, is called a structural formula. For the substance we are considering, it will look like this: (-CH2-CH-CH3-) . Obviously, the generally accepted valency of atoms in organic chemistry is preserved in this case as well. The formula of polypropylene or polypropene shows what kind of monomer unit underlies the compound. It is formed from the unsaturated hydrocarbon (alkene) propene or propylene. His empirical formula is: С3Н8.
Initial monomer
The monomer formula for producing polypropylene is: (-CH2-CH-CH3-). If this fragment is repeated several hundredtimes, then we get a whole macromolecule of a synthetic polymer, which is the material in question. In addition, we have already indicated that, in general, the usual alkene - propene should be considered the starting material for the polymerization reaction. It is the monomer of polypropylene. The structural formula will be written as CH3-CH=CH2. When the double bond is broken during polymerization, the desired fragment is formed. The same monomeric link that, repeating, forms a polymer macromolecule.
Physical and chemical properties
Polypropylene formula (-CH2-CH-CH3-) allows you to judge about its physical and chemical characteristics. We list the main ones.
- Physical properties of this polymer: density 0.91g/cm3, hard, abrasion resistant, non-corrosive. Color white, opaque. There is no smell. It is insoluble in water and organic solvents at ordinary temperatures. Above 100 0С dissolves in hydrocarbon compounds. It begins to soften after 140 0С, at 170 0С it melts. It has heat and frost resistance.
- Chemical properties. From the point of view of activity, polypropene can be attributed to practically inert substances. It is able to interact only with especially strong oxidizing agents: fuming nitric, chlorosulfonic acids, oleum, active halogens (fluorine, chlorine). It does not interact with water at all, even at elevated temperatures. With oxygenreacts only when irradiated with ultraviolet light, the process is accompanied by the destruction of the polymer. In organic solvents, it swells and dissolves with increasing temperature.
The indicated properties can also be attributed to the technical characteristics of the material itself, which is used in industry. However, not all polypropylene is the same. There are special stabilizer additives that create different grades of the polymer in question.
Material specifications
There are several basic properties that polypropylene material has. Its characteristics are as follows:
- When heated, it can melt, softening beforehand.
- Not conductive.
- Shock-resistant, wear-resistant.
- Resistant to abrasion.
- Grows old when exposed to the sun and oxygen, but the process is quite slow.
- As a polymer has a small molecular weight.
- White, translucent, tasteless and odorless.
- When burned, it does not emit harmful substances, it emits a light floral aroma.
- It is flexible, durable, resistant to various kinds of pollution.
- Possesses heat and frost resistance.
All the indicated properties of polypropylene as a material allow it to be used for various needs. It is easy to use, easy to maintain and use in practice in any sector of the national economy.
Total can bedistinguish three main varieties of this material:
- attactic;
- syndiotactic;
- isotactic.
The main difference in them is the spatial structure of the molecule. Specifically, the location of methyl groups in the chain. Also, the technical characteristics are influenced by stabilizing additives, the number of monomer units in the macrostructure.
Produce this material either in the form of crystalline granular structures, or in the form of fibers, sheets.
Usage areas
Polypropylene material is used for the production of various films, packaging containers, food containers. It is from it that ordinary plastic cups and other disposable tableware are made. This material is used to make durable, chemical-resistant polypropylene plumbing pipes.
It is also used to create soundproof materials. Adhesive tape is also a type of polypropylene.
Attactic material goes to production:
- mastic;
- glues;
- putty;
- adhesive tapes;
- road surfaces and more.
A large number of polypropylene sheets, fibers are used to make toys, stationery, household and household items.
