Polypropylene - melting point, properties and characteristics

Polypropylene, the melting point of which should be known to you, if you plan to use the material for personal purposes, are a thermoplastic synthetic nonpolar polymer that belongs to the class of polyolefins.

For reference

Still known is polypropylene as a polymerization product of propylene. The material is white in color and has a solid structure. It is produced by the polymerization of propylene. Polymerization is carried out under the influence of a pressure of 10 atmospheres, while maintaining a temperature of 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. The melting point 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 point is much higher and varies from 165 to 170 ° C. This material is resistant to chemical reagents.

Physical and mechanical properties and technical characteristics

Polypropylene, the melting point of which was mentioned above, differs from polyethylene by a lower density, which is 0.91 g / cm³. This value is common to plastics. This material is also more solid, 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 stress-corrosion cracking. Polypropylene is resistant to light, as it is to oxygen. The introduction of stabilizers lowers 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 in tension, depending on the temperature and speed of application of the load. The lower the rate of stretching, the higher the value of mechanical properties. In tension, the breaking stress varies from 250 to 400 kgf / cm², while the elongation at break is 200 to 800%.

The melting point of polypropylene sheet, which was mentioned above, is not the only characteristic that is of interest to private consumers. They are sometimes disturbed by the flexural modulus as well. In the described case, it can vary from 6700 to 11,900 kgf. At the yield point, the elongation is equivalent to 10-20%. Impact strength with notch is 33-80 kgf * cm / cm². The Brinell hardness is 6-6.5 kgf / mm².

Application area

Polypropylene is widely used. The material is used for the production of films, here it is possible to classify their packaging variety. Among other products it is necessary to distinguish:

• bags;
• Pipes;
• plastic cups;
• Container;
• Details of technical equipment;
• Household goods;
• Electrical insulating material;
• Nonwoven material.

In construction, polypropylene also found its use, where it is used for vibration and noise insulation of interfloor overlappings, as well as in systems that are equipped with the technology of "floating floor". When polypropylene copolymerizes with ethylene, it is possible to obtain a non-crystallizable copolymer. It is able to exhibit the characteristics of rubber, which has resistance to aging and is highly chemical resistant.

For heat and vibration isolation, expanded polypropylene is widely used. The melting point of polypropylene sheet was mentioned above, but this characteristic is not the only one that should interest you before purchasing products from this material. It should also be known that polypropylene foam is very similar in properties to polyethylene foam. But expanded polystyrene can be replaced with a decorative extrusion profile made of expanded polypropylene. To obtain putty, road coatings, construction adhesives, mastics and sticky films, atactic polypropylene is often used. The scope of polypropylene in Russia was as follows:

• 38% - container;
• 30% - threads;
• 18% - films;
• 6% - pipes;
• 5% - polypropylene sheets;
• 3% - other.

Melting temperature 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 the superheated steam. If we take into account this number, then polypropylene could be used for any water supply system, over which water is transported at an arbitrarily high temperature.

But in this issue it's not so simple. Plasticity is an additional feature of the material. At break, polypropylene has a relative elongation that varies between 200 and 800%. This indicates that if a certain weight is applied to the pipe, the product will stretch out into a long tube and then break off.

As a 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 today the most popular in production. This is due to the peculiarities of this type of material, where the side groups of CH3 have a special position, which are unusual in relation to the main chain. Such a sphere determined the main qualities, among them it should be noted: the ability to maintain shape under the influence of high temperatures, hardness and high strength.