Polypropylene is a thermoplasticpropene polymer. It is produced by the propylene polymerization technology using metal complex catalysts. The parameters for obtaining this material are similar to those for which low-pressure polyethylene is manufactured.
Depending on which catalystused, you can achieve any type of polymer or mixtures thereof. The melting point of polypropylene is one of the important characteristics of this material. It has the appearance of white powder or granules, the bulk density of which varies to 0.5 g / cm ³. The described material can be colored, stabilized or unpainted.
According to the molecular structure, polypropylene is divided into several main varieties, among them:
Material stereoisomers differ in physical,mechanical and chemical characteristics. For example, atactic polypropylene has the form of a rubbery material, which is characterized by high fluidity. The melting point of polypropylene for extrusion in this case is about 80 ° C, while the density can reach 850 kg / m³.
В диэтиловом эфире этот материал растворяется very good. According to its properties, isotactic polypropylene differs from the one described above and has a high modulus of elasticity, its density reaches 910 kg / m³, whereas the melting point varies from 165 to 170 ° C. In this variety, polypropylene is characterized by excellent resistance to chemical reagents.
Today is very common usepolypropylene. The melting point of this material varies with individual species. Quite often it is compared with polyethylene, but polypropylene is not so high density, it is 0.91 g / cm ³. In addition, polypropylene is harder, resistant to abrasion and tolerates exposure to temperature.
The level of its softening starts at140 ° C, while the melting point reaches 175 ° C. Material corrosion is not subject to cracking. It is resistant to oxygen and light, but this sensitivity is reduced if stabilizers are added to the ingredients in the manufacture of polypropylene.
In various industries todayMany varieties of polypropylene are used. The melting point of this material expands the scope. Elongation at break in percent can vary from 200 to 800%. The tensile yield strength is equal to the limit from 250 to 350 kgf / cm². The notched impact strength varies from 33 to 80 kgf · cm / cm², while the Brinell hardness is equal to the limit from 6 to 6.5 kgf / mm².
If you plan to purchase some products frompolypropylene, the melting point of this material should be known to you. We are talking about it in the article. From it you can learn and other chemical properties. For example, the material is chemically stable, and in organic solvents it only slightly swells. If the temperature rises to 100 ° C, the material will dissolve in aromatic hydrocarbons. In this case we are talking about toluene and benzene.
По той причине, что в полипропилене содержатся tertiary carbon atoms, it is resistant to oxygen when exposed to ultraviolet radiation and elevated temperatures. This causes the tendency to aging compared with polyethylene. Under the influence of aggressive media, polypropylene is not as strong as polyethylene, it is subject to cracking. It is able to undergo cracking tests even under stress.
Quite often modern consumerThe melting point of polypropylene is of interest. Pipes this applies if you plan to carry out the arrangement of the heating system. When exposed to a temperature of 140 ° C, the material becomes soft, while it loses its shape. Whereas if the temperature rises to 170 ° C, then the melting stage will begin. At the same time, it will cease to be solid and will lose the ability to maintain its technical characteristics and form.
Heating systems at this level of temperature are notare designed, therefore, polypropylene pipes are suitable for supplying water to the system. Manufacturers usually state that the maximum possible temperature of polypropylene pipes is 95 ° C. Products are able to withstand a higher temperature level, but for a short time. If pipes are used for a long time at temperatures above 100 ° C, then their service life will decrease.
When temperature drops, polypropylene willvary in size. When heated, it will expand, and when cooled - shrink. Under the influence of high temperatures, the pipes may start to sag between fastenings, and you will notice bloating in the outer layer.
You can also use products frompolypropylene. The melting point of such tubes may be different. This should be taken into account if you have products of the brand PN20. In this case we are talking about a pipe, the working temperature of which reaches 60 ° C. But if we are talking about the product PN25, then this indicates that it will be able to withstand temperatures up to 95 ° C.
With certainty we can say thatPolypropylene gasket is allowed near the smoke shafts. The melting point of polypropylene, however, does not indicate that the pipes should not be protected. Experts recommend purchasing reinforced products that are less susceptible to deformation when exposed to high temperatures. Therefore, pipes must be additionally protected with insulation and have an inner fiberglass or aluminum layer. This will protect the pipes from expansion and prolong their service life.
