Formula of polypropylene. Properties and application of polypropylene

Polymers and materials made of them, household items, equipment - this is 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, which have a number of important technical characteristics. One such is polypropylene. The chemical formula of this compound, the features of its properties and the structure of the molecule, will be considered in the course of the article.

Polymers are a general characteristic

This class of compounds includes those that have a very high molecular weight. After all, polymers are complex organic compounds, consisting of repeatedly repeating monomeric units, which can range from several tens to hundreds, thousands and millions.

Among all polymers, the following groups can be distinguished:

1. Natural origin - proteins, nucleic acids, ATP molecules and so on.
2. Artificial - those that are based on natural, but have been chemically modified to improve performance. For example, artificial rubbers.
3. Synthetic - those that are created only through chemical reactions, synthesis in the laboratory and production plants. Examples here are synthetic fabrics and fibers, polyethylenes, synthetic rubbers, polyvinylchloride, polypropylene and others.

All the 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 (-CH ₂ -CH ₂ -) _n . This is polyethylene. Areas of its use are known. This household needs (economic film), and industrial and food industry (packaging material). However, although he is the most common, but not the only representative, which is extremely important for a person. Also it is possible to name such polymers, as:

• Polyvinyl chloride;
• polypropylene;
• Polyisobutylene;
• Polystyrene;
• Teflon;
• Polyvinyl acetate and others.

It is in the construction business, as well as for the production of utensils, that a material such as polypropylene plays an important role. Therefore, let's consider its particular features from the chemical point of view.

The formula of polypropylene

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 record. In this case, the polypropylene formula looks like this: (C ₃ H ₆ ) _n . The last n is the degree of polymerization, that is, the number of structural precursors in the macrochain.

Such a record allows us to draw a conclusion about the qualitative and quantitative composition of the molecule. Polypropen consists of carbon and hydrogen atoms, and their quantity in the monomer unit is 3/6, respectively, and in the general chain it depends on the index n. If we talk about the very structure of the compound, the order of the bonds of atoms in a molecule, then another form of recording of matter is needed.

Polypropylene: structural formula

The form of the record, which shows the order of the connection of atoms in the molecule, is called the structural formula. For the substance under consideration, it will have the following form: (-CH ₂ -CH-CH ₃ -) _n . Obviously, the conventional valence of atoms in organic chemistry is preserved in this case. The formula of polypropylene or polypropene shows which particular monomer unit is the basis of the compound. It is formed from an unsaturated hydrocarbon (alkene) propene or propylene. Its empirical formula is: C ₃ H ₈ .

Starting monomer

The monomer formula for the production of polypropylene is as follows: (-CH ₂ -CH-CH ₃ -). If this fragment is repeated several hundred times, then we get the whole macromolecule of the synthetic polymer, which is the material under consideration. In addition, we have already indicated that generally the starting material for the polymerization reaction is ordinary alkene-propene. He is the monomer of polypropylene. The structural formula will be written as CH ₃ -CH = CH ₂ . When a double bond is broken, a desired fragment is formed during the polymerization. The same monomeric link, which, repeating itself, forms the macromolecule of the polymer.

Physical and chemical properties

The formula of polypropylene (-CH ₂ -CH-CH ₃ -) _n allows to judge its physical and chemical characteristics. Let's list the main ones.

1. The physical properties of this polymer: a density of 0.91 g / cm ³ , a solid, abrasion-resistant, does not corrode. Color white, opaque. Odor is absent. In water, organic solvents at ordinary temperatures are insoluble. At an index of more than 100 ⁰ C it dissolves in hydrocarbon compounds. Soften begins after 140 ⁰ C, at 170 ⁰ C melts. It has heat and frost resistance.
2. Chemical properties. From the point of view of activity, polypropylene can be attributed to practically inert substances. It is able to interact only with particularly strong oxidizing agents: fuming nitric, chlorosulfonic acids, oleum, active halogens (fluorine, chlorine). With water, it does not interact at all, even at elevated temperatures. With oxygen reacts only when irradiated with ultraviolet, the process is accompanied by the destruction of the polymer. In organic solvents, as the temperature rises, it swells and dissolves.

Designated properties can 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 additives, stabilizers, with which different types of polymer are created.

Technical characteristics of the material

It is possible to identify several basic properties that the polypropylene material possesses. Its characteristics are as follows:

1. When heated, it can melt, pre-softening.
2. Does not possess conductor properties.
3. Shock resistant, durable for wear and tear.
4. It is resistant to abrasion.
5. Aging when exposed to the sun and oxygen, but the process is slow enough.
6. As the polymer has a small molecular weight.
7. Has a white color, is semi-transparent, has no taste and smell.
8. When burned, it does not emit harmful substances, produces a slight floral fragrance.
9. It is flexible, durable, resistant to various kinds of pollution.
10. It has 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, convenient to care and use in the practical activities of any branch of the national economy.

There are three main types of this material:

• Attaktichesky;
• Syndiotactic;
• Isotactic.

The main difference in them is the spatial structure of the molecule. And specifically - the location of methyl groups in the chain. Also, the technical characteristics are affected by stabilizing additives, the number of monomer units in the macrostructure.

This material is produced either in the form of crystalline granular structures, or in the form of fibers, sheets.

Areas of use

Material polypropylene is used for the production of various films, packaging containers, food containers. It is from it that ordinary plastic cups and other items of disposable dishes are made. This material is used for the manufacture of strong, chemical resistant polypropylene plumbing pipes.

It is also used to create noise-proof materials. Sticky tape is also one of the varieties of polypropylene.

Attaktichesky material goes on manufacturing:

• Mastic;
• Adhesives;
• Putty;
• Sticky tapes;
• Road surfaces and so on.

A large number of polypropylene sheets, fibers are spent on making toys, office supplies, household and household items.