Polypropylene, the melting point of which should be known to you if you plan to use the material for personal purposes, is a thermoplastic synthetic non-polar polymer, which belongs to the class of polyolefins.
For reference
Polypropylene is also known as a polymerization product of propylene. The material is white and has a solid structure. It is produced by propylene polymerization. Polymerization is carried out under a pressure of 10 atmospheres, while maintaining a temperature within 80 ° C.
Molecular structure and melting point
Polypropylene, the melting point of which will be named below, is divided into three types according to the type of molecular structure:
- atactic;
- syndiotactic;
- isotactic.
Atactic polypropylene is a rubbery material that has a high degree of fluidity. Its melting temperature is 80 ° C, while the density is 850 kg / m³. This material is also characterized by high solubility in diethyl ether.
It differs in its characteristics from the above isotactic polypropylene in that it has a high modulus of elasticity, its density reaches 910 g / m³, while the melting temperature is much higher and varies from 165 to 170 ° C. This material is resistant to chemicals.
Physico-mechanical properties and specifications
Polypropylene, the melting point of which was mentioned above, differs from polyethylene in lower density, which is 0.91 g / cm³. This value is common to plastics. The described material is also harder, this is manifested in the fact that it has a high resistance to abrasion.
Among other things, polypropylene is heat-resistant, because it begins to soften when the temperature reaches 140 ° C. The melting point is 175 ° C, in addition, the material is practically not subjected to corrosion cracking. Polypropylene is resistant to light, as is oxygen. The introduction of stabilizers reduces the sensitivity even more.
Polypropylene, the melting point of which you may be interested in, if you plan to use this material, will behave differently when stretched, depending on the temperature and load application speed. The lower the tensile speed, the higher the value of the mechanical properties. When tensile, the breaking stress varies from 250 to 400 kgf / cm², while the elongation at break is a limit of 200 to 800%.
The melting point of polypropylene sheet, which was mentioned above, is not the only characteristic that private consumers are interested in. Sometimes they are also concerned about the modulus of elasticity in bending. In the described case, it can vary from 6700 to 11900 kgf. At yield strength, elongation is equivalent to 10-20%. Impact strength is 33-80 kgf * cm / cm². Brinell hardness is 6-6.5 kgf / mm².
Application area
The use of polypropylene is quite wide. The material is used for the manufacture of films, including their packaging variety. Among other products, it is necessary to highlight:
- bags;
- pipes;
- plastic cups;
- tara;
- details of technical equipment;
- household items;
- electrical insulating material;
- nonwoven fabric.
Polypropylene has also found its application in construction, where it is used for vibration and noise insulation of floors, as well as in systems that are equipped using the "floating floor" technology. When polypropylene is copolymerized with ethylene, a non-crystallizable copolymer is obtained. It is able to exhibit the characteristics of rubber, which has resistance to aging and is characterized by increased chemical resistance.
Polypropylene is widely used for heat and vibration isolation. The melting point of polypropylene sheet was mentioned above, however, this characteristic is not the only one that should interest you before purchasing products from this material. You should also know that polypropylene is very close in properties to polyethylene foam. But expanded polystyrene can be replaced with a decorative extrusion profile made of expanded polypropylene. Atactic polypropylene is often used to obtain putties, pavements, building adhesives, mastics and sticky films. The scope of polypropylene in Russia was as follows:
- 38% - containers;
- 30% - threads;
- 18% - films;
- 6% - pipes;
- 5% - polypropylene sheets;
- 3% - other.
Melting point of polypropylene pipes
The melting point of polypropylene pipes is one of those characteristics that most often interests the modern consumer. This material will begin to soften at 140 ° C, while melting at 175 ° C. The last parameter is the temperature of superheated steam. If this number is taken into account, then polypropylene could be used for any water supply system through which water with an arbitrarily high temperature is transported.
But in this matter, everything is not so simple. Plasticity acts as an additional feature of the material. At break, polypropylene has a relative elongation, which varies from 200 to 800%. This indicates that if a certain weight is applied to the pipe, the product will stretch into a long tube and then break.
In conclusion: the nature of polypropylene
The properties of polypropylene, the characteristics and nature of this material will allow you to understand in which area it is best to use it. Isotactic propylene is considered the most popular in production today. This is due to the characteristics of this kind of material, where the special position is given by the side groups of CH3, which are unusual in relation to the main chain. A similar area identified the main qualities, among them it should be highlighted: the ability to maintain shape when exposed to high temperatures, hardness and high strength.