Polypropylene is quite common today in various fields of human activity. What is it, you can find out by reading the article. This substance is indicated by two capital letters PP and is a thermoplastic polymer of propylene, which is also called propene.
Definition
Get it by polymerization of propylene with the participation of metal complex catalysts according to the type of Ziegler-Natta analogues. The parameters required for the formation of polypropylene are close to those necessary for the production of low-pressure polyethylene. Depending on which catalyst is used, any type of polymer or mixture thereof may be obtained.
If you are interested in polypropylene, what is it in terms of chemical characteristics and general properties, you should know that the substance has the form of a powder or granules of white color. The bulk density of the latter varies from 0.4 to 0.5 g / cm³. The substance is released painted and unpainted, stabilized.
Specifications
If we compare polypropylene with polyethylene, the first one is less dense, for this substance this indicator is 0.90 g / cm 3 , which is the lowest value for plastics. The material is harder, it is heat-resistant, resistant to abrasion, softening starts at +140 ˚. The melting point is +175 ˚. The material is practically not susceptible to corrosion cracking.
When studying the question that this is polypropylene, you should know that it is resistant to light and oxygen, but this characteristic decreases with the introduction of stabilizers. The behavior of the substance under tension depends on the temperature and the speed of application of the load, which manifests itself to a greater extent than that of polyethylene. With a decrease in the tensile speed, the index of mechanical properties increases. When this parameter is quite high, the breaking stress becomes lower than the tensile strength.
additional characteristics
Polypropylene exhibits chemical resistance. Only oxidizing agents such as fuming nitric acid, oleum, chlorosulfonic (sulfuric acid monochloride) acid or halogens can have a strong effect on it. Quite insignificantly, and at room temperature, 30 percent hydrogen peroxide and concentrated 58 percent sulfuric acid act. Contact with these reagents may remain without polymer degradation if the temperature is within +60 ° C or lower.
Polypropylene swells in organic solvents at room temperature. If the temperature is above 100 ˚, then the material dissolves in aromatic hydrocarbons according to the type of toluene and benzene.
Industrial and domestic use
Today polypropylene is very common. What is it and how to use the material, you can understand if you get closer to the areas of its application. The raw materials are used for films, the manufacture of pipes, containers and parts of technical equipment. Household items and various non-woven materials are made from it. It forms the basis of electrical insulation materials, and in construction it is used for the manufacture of noise and vibration insulation of floors between floors.
Polypropylene found its wide distribution in the formation of the "floating floor" system in everyday life. Non-crystallizable copolymers are obtained by polymerization of propylene with ethylene. As a result, the material acquires the properties of rubber and has increased chemical resistance. During operation, it effectively resists aging.
The best decision
If you want to choose the best polypropylene, you should understand the issue from different points of view. Among other market offers, you can find polypropylene pipes from different manufacturers. Only positive reviews received products of German production, among other companies from Germany should be highlighted:
- Rehau;
- Aquatherm;
- Banninger;
- Wefatherm.
Czech pipes take the second place, among them ECOPLASTIC and FV-Plast stand out especially. The cheapest and inferior products are Turkish-made pipes, you can recognize them by one of the following names:
China is not happy with the quality, but in this rule, as in any other, there are exceptions. Chinese polypropylene pipes BLUE OCEAN have worked well. You can also choose the best products according to other features. Products are single-layer and multi-layer. The latter can reduce thermal elongation and have a foil reinforcement. Such pipes may be perforated or smooth.
You can also choose a high-quality polypropylene pipe based on the type of reinforcement. Sometimes the foil layer is located outside. Another type of reinforcement is the inner aluminum layer. It allows you to connect the layers without the use of glue. Fiberglass is also used for reinforcement.
Pipe diameters
In order to get better acquainted with polypropylene, you should find out what are the diameters of pipes made of this material. The described parameter can be external and internal. The first varies from 16 to 110 mm, while the inside - from 16.2 to 90 mm. If we consider the dimensions of the pipes in more detail, then the wall thickness can vary from 1.9 to 10 mm.
As for the area of use, large diameter pipes are used when laying water, sewage and heating to residential neighborhoods and houses, sports complexes, public buildings, as well as hotels. Such products are used for industrial needs. For example, if the diameter of the polypropylene is 500 mm, such a pipe is used to supply cold drinking water to the metropolitan areas from the storage pools. Polypropylene pipes are not used for heat transfer due to the high heat load, which entails the softening of polymer lines.
Description of sheets from software. Areas of use
Polypropylene sheets are used for transportation and storage of alkalis and acids, as well as chemicals due to the fact that the material is well resistant to chemical, temperature and other influences. It is stable and can be used in the food industry for the storage of various liquids and food products. Such sheets may be monolithic or composite. The former are also called homogeneous, and the latter are called lightweight. They have an internal sub-foam and an external monolithic decorative layers.
Among the main properties should be highlighted:
- fairly low density;
- very high strength;
- high frost resistance;
- good chemical resistance;
- safety for human and animal health;
- good susceptibility to machining;
- excellent dielectric characteristics.
Laying the heating system and soldering pipes
With your own hands from polypropylene, you can lay the heating system in your house or apartment. The material today is affordable and fairly lightweight. Before starting work, it is necessary to identify the joints and understand the method of installing pipes. To solder, the product must be cut to size. The joints should be flat and have a right angle. Sections are degreased, chips are removed from the surface after cutting.
The pipe is installed in the centralizer. This will achieve geometric accuracy of the connection. Fittings are then put on the docking points. Soldering polypropylene is carried out using an inverter. The device heats up, after which you can begin to manipulate.
You can also use electric welding couplings. In this case, the installation is carried out in them. If it is necessary to connect polypropylene products to the system of metal pipes, use flanges. On the one hand, they have threads for tapping into metal pipes. On the other hand, the product has a smooth shutter for mounting on plastic.
If you plan to use polypropylene for heating, it is important to determine the welding time of the joints, which will depend on the diameter of the pipes. All elements of the system are pre-recorded in the room. They must be warmed to room temperature. Using the calculated data, you need to apply the cutting location on the surface of the products with a marker. Work is best done with special scissors. Slices are wiped with a solution of alcohol. Use a dry cloth to remove any residual dirt. Then comes the turn of the nozzle for the soldering apparatus. You must select the appropriate diameter. The nozzle is degreased and installed horizontally. It is heated to 265 ° C.
The pipe and fitting are placed in the hole of the heater. Connected elements heat up for a while. After they are removed from the product and insert the pipe into the fitting. At this stage, it is important to sustain the required time. The connected elements should not be touched until they are completely cooled.
Finally
Polypropylene is a chemically resistant material. Only certain acids and oleum can have some effect on it. The destruction of polypropylene occurs only with prolonged contact with reagents such as sulfuric acid and hydrogen peroxide. Material swelling can occur in organic solvents. Upon contact with aromatic hydrocarbons and a temperature of 100 ° C and above, dissolution occurs.