Polyethylenes are a family of resins that are obtained by polymerization of ethylene gas (C2H4) and are abbreviated as PE. Various properties such as density, melt flow index (MFI), crystallinity, branching and network formation, molecular weight and molecular weight distribution can be controlled through the catalyst and polymerization method. Polyethylenes are classified based on their density, which is affected by the size of the polymer chain and the type and number of branches in the chain. According to the sales volume, the most important grades of polyethylene are heavy polyethylene (HDPE), light polyethylene (LDPE) and linear light polyethylene (LLDPE), which are presented in the table below.
| LLDPE | LDPE | HDPE | Propertiy | ||
|---|---|---|---|---|---|
|
0.916-0.93 |
0.91-0.925 |
0.94-0.965 |
Density (g/cm3) |
||
|
50-65 |
30-50 |
80-90 |
(%) Cristallinity |
||
|
115 |
98-115 |
130-137 |
Melting Temp (°C) |
||
|
4-16 |
8-45 |
20-40 |
Yeild strength (MPa) |
||
|
0.1-100-150 |
Melt index range (g/10 min) |
||||
Polyethylene is widely used in the production of all kinds of plastic appliances used in the kitchen and food industry. LDPE is used in the production of light plastic containers as well as plastic bags. HDPE is used in the production of milk and liquid containers and all kinds of plastic kitchen utensils. MDPE is usually used in the production of plastic pipes and pipe fittings. Among the most important applications of linear light polyethylene, the following can be mentioned:
Polyethylene was first accidentally synthesized by the German chemist “Hans Von Pechmann”. In 1898, while heating diazomethane, he synthesized a white waxy compound, which was later named polyethylene. Polyethylene was discovered for the first time by the industrial synthesis method, by accident by Azik Naust and Rinolregisson (from ICI chemists) in 1933. These two scientists obtained a wax-like substance by heating a mixture of ethylene and benzaldehyde under high pressure. Heavy polyethylene is initially uniform, pure and opaque, it is not colored and if necessary, pigments are added to them. These materials are used in white, red, blue, yellow, green, black, and sometimes even the color of their raw materials. They are electrically insulating and will be destroyed by direct heat. The most common and widely used type of plastic that was created was heavy polyethylene (HDPE). The molecular chain in this type of polymer is compact, which increases its density. Therefore, the flexibility is greatly reduced. Although this type of polymer has less impact resistance than light polyethylene, its resistance to chemicals is good as well as its resistance to environmental breaking stresses. Heavy polyethylene is produced in various grades, which are as follows:
Polyethylene production technologies use natural gas and naphtha as feed.
Low pressure polymerization is divided into four processes, slurry, solution, slurry with Ziegler catalyst, and gas phase, according to the type of reactor and process conditions used.
Unit 5, No. 7, Imam Khomeini St., Emad al-Islam St., Sahil St., Noor City, Royan City, Mazandaran Province
Unit 512, 5th floor, Palmyra commercial-administrative complex, Shahid Madani St., Narmak, Tehran, Tehran Province
Royan Petro Kimia Company (private shares) was established in 2013 with the registration date of 1663. . In the summer of 2014, this company became a member of the Association of Credit and Investment Banking Consultants and in 2022 succeeded in upgrading its rank to grade “B-3” in the fields of feasibility studies and investment opportunities in the petrochemical, refinery and chemical absorption industries.
Unit 5, No. 7, Imam Khomeini St., Emad al-Islam St., Sahil St., Noor City, Royan City, Mazandaran Province
Unit 512, 5th floor, Palmyra commercial-administrative complex, Shahid Madani St., Narmak, Tehran, Tehran Province
Royan Petro Kimia Company (private shares) was established in 2013 with the registration date of 1663. In the summer of 2014, this company became a member of the Association of Banking & Credit Investment Consultants and in 2022 succeeded in upgrading its rank to grade “B-3” in the fields of feasibility studies, introducing investment opportunities and financing in petrochemical, refinery and chemical industries.
