Polypropylene – properties, applications and everything you need to know about it

The category of products called “Plastics or plastics” includes a very wide range of materials with a wide variety of properties. In this article, we will talk about the most widely used, versatile type of polymeric material for the production of such products as polypropylene plastic.

What is polypropylene (PP)?

Polypropylene is a synthetic thermoplastic substance. It is produced as a result of the polymerisation of propylene with the use of catalysts. The chemical accelerator is often a mixture of titanium tetrachloride (TiCl4) and Lewis acid (AlR3). Due to its high strength and hardness characteristics, polypropylene material is widely used in various sectors of the economy.

Chemical and physical properties of PP

As mentioned above, polypropylene is highly valued for its unique characteristics in a wide variety of industries. In terms of production, this synthetic material is particularly in demand due to the following properties:

• Safety for the environment and human health. Numerous studies by scientists from different countries have proven that propylene is a non-toxic and environmentally friendly material. Therefore, PP is actively used for the production of containers for drinking water, liquid and bulk food products.
• Dielectric properties. Polypropylene is used as an insulating sheath for electrical wires, for the production of socket and switch parts, electrical appliance housings, etc.
• Low degree of vapour permeability. This quality provides polypropylene products such as plastic canisters, containers and other containers, as well as plastic suitcases and cases, with excellent water resistance.
• It is neutral to many alkalis and chemically active solutions. Polypropylene also has the chemical properties to be exposed to non-polar substances such as chloromethane (CH3Cl), benzene (C6H6) or tetrachloromethane (CCl4).
• The absence of any odour makes polypropylene comfortable for consumers of all ages and social statuses.
• The thermoplastic properties of polypropylene make it the best material option for the manufacture of products of various sizes, shapes and purposes. To pour into moulds or form blanks, either molten polypropylene or heated to a plastic state is used. After cooling, the polymer fully restores its original strength properties. But it should be remembered that PP begins to disintegrate when heated above +270°C.

Both primary and secondary polypropylene granules are used as raw materials for the production of polypropylene products. The first type is produced as a result of a chemical reaction. The second type is produced by recycling.

Applications for polypropylene

Polypropylene is in demand in many industrial sectors – its properties and applications are appreciated in various areas of the modern economy. Today, it is difficult to find or identify places where this type of polymer is not used. Even in small quantities, this versatile, durable and safe material can be found almost everywhere. The most popular industries where propylene is used are:

• Food processing, packaging and containers. Food-grade polypropylene film is widely used for packaging semi-finished products, food, vegetables and fruits. Plastic bottles, food containers, canisters and barrels are very popular.
• Chemical industry. Production of plastic water and sewage pipes, water treatment systems and septic tanks. Production of domestic and industrial tanks, plastic swimming pools and much more.
• Pharmaceutical industry. Due to the fact that polypropylene has characteristics that meet strict sanitary, hygienic and environmental requirements, it is used to make laboratory glassware, diagnostic equipment, disposable syringes and other medical supplies.
• Electrical and cable and wire products. Since polypropylene is a dielectric plastic, it is used as an insulating material in the production of electrical, telecommunications, telephone and other types of wires. PP is used to make fuse housings, measuring instruments, electronic equipment, insulators and much more.
• Light industry. Polypropylene has such advantages as strength, resistance to mechanical stress, water resistance and resistance to temperature extremes. It is used to make plastic suitcases, garbage containers, buckets and other types of garden tools. It is also widely used in the manufacture of household appliances and auxiliary home equipment.
• Textile products. Polypropylene is used in the manufacture of carpets and synthetic fabrics. Synthetic fibres produced using
• Heat-Set technology are almost identical in their characteristics to natural animal wool.
• Furniture production. Racks, cabinets, armchairs, tables, deckchairs and other types of plastic furniture are produced for use both indoors and outdoors.
• Construction industry. Fencing elements (polypropylene fences, protective nets and films), plastic panel formwork, plastic containers (bags, big bags, cans, buckets, etc.) for building mixtures, paints and varnishes, and bulk building materials.
• Automotive industry. The following propylene products are used in car manufacturing: front and rear bumpers, fenders, exterior weighting elements, interior decorative lining and even body parts.

Polypropylene is also widely used in other areas of industrial production and in agriculture.

Benefits and harms of polypropylene

At the moment, polypropylene is rightly considered the safest and most environmentally friendly polymeric material. This statement is true only if the operating rules are followed. The main limiting factor for polypropylene products is temperature. When heated, this polymer begins to release phenols, formaldehyde esters, metal dioxides and other substances into the environment. Therefore, the use of polypropylene is prohibited for the production of crockery, containers or pipes that will be exposed to high temperatures during operation.
It is also not recommended to store alcoholic beverages and vegetable oils in polypropylene containers for a long time. These liquids provoke the release of heavy metal compounds, aldehydes and other chemical compounds.
To eliminate the risks of negative impacts of polypropylene on human health and the environment, a number of simple rules should be followed:

• Use pipes, containers and utensils made of high-quality plastic from a reliable manufacturer.
• If plastic products have or develop a characteristic chemical odour, stop using them immediately.
• During use, do not expose polypropylene to high heat.
• Remember that plastic products are not long-lasting.

Compliance with these simple recommendations guarantees safe and comfortable use of any products and polypropylene.