There are several principles or methods of production of polypropylene and their contents, and sever

Slurry method. in diluent.

such as hexane), which is the earliest industrialized and the most produced method so far. Liquid-phase bulk method. Polymerization in liquid propylene at 70 and 3 MPa.

Gas phase method. Propylene is polymerized in a gaseous state. The latter two methods do not use diluents, have a short process and low energy consumption.

The liquid-phase bulk method has now shown an advantage over the latter.

Polyethylene synthesis methods and characteristics are as follows:

1. High-pressure method.

A method of polymerizing ethylene into low-density polyethylene with oxygen or peroxide as an initiator.

Ethylene enters the reactor after secondary compression, and is polymerized into polyethylene under the pressure of 100 to 300MPa, temperature of 200 to 300 degrees Celsius and initiator.

Features: It is polymerized with organic peroxide as the initiator under a high pressure of 100 to 300MPa, and this polyethylene can also be called high-pressure polyethylene. Its density is in the range of to per cubic centimeter.

2. Low-pressure method.

There are three kinds of slurry method, solution method and gas phase method, except for the solution method, the polymerization pressure is below 2MPa.

Slurry method: The generated vintan polyethylene is insoluble in solvents and is slurry-like. The slurry method polymerization conditions are mild and easy to operate, and alkyl aluminum is commonly used as activator, hydrogen is used as molecular weight regulator, and kettle reactors are mostly used.

Solution method: polymerization is carried out in solvent, but ethylene and polyethylene are dissolved in solvent, and the reaction system is a homogeneous solution. The reaction temperature (greater than or equal to 140 degrees Celsius) and pressure (4 to 5 MPa) are the first to be lifted.

Gas phase method: ethylene is polymerized in a gaseous state, and a fluidized bed reactor is generally used.

Features: Density to per cubic centimeter, high density value, high tensile strength and tear strength.

3. Medium pressure method.

High-density polyethylene is produced by polymerizing ethylene at medium pressure in a ring tube reactor with a chromium-based catalyst loaded on silica gel. Processing and application: It can be processed by blow molding, extrusion, injection molding and other methods, and is widely used in the manufacture of films, hollow products, fibers and daily miscellaneous products.

Features: Improved Ziegler catalyst is used, and the purity and performance are between high-pressure polyethylene and low-pressure polyethylene in many aspects.

Polyethylene is divided into high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) according to the polymerization method, molecular weight and chain structure.

The differences between them are:

1. Structural features.

Low-density polyethylene (LDPE): more long branched chains 8 40 1000C;

High-density polyethylene (HDPE): rarely short branched < 8 1000C;

Linear low-density polyethylene (LLDPE): short branched chain (controllable).

2. Performance. Low-density polyethylene (LDPE): low strength, low melting point (105-110), good toughness;

High-density polyethylene (HDPE): high strength, high melting point (130-135);

Linear low-density polyethylene (LLDPE): Somewhere in between.

3. Production method.

Low-density polyethylene (LDPE): high-pressure radical polymerization;

High-density polyethylene (HDPE): low-pressure coordination polymerization (Z-N);

Linear low-density polyethylene (LLDPE): low-pressure coordination polymerization (Z-N).

1. Slurry method. Polymerization in diluents such as hexane is the earliest industrialized and by far the most produced method.

2. Liquid phase bulk method. Polymerization in liquid propylene at 70 and 3 MPa.

3. Gas phase method. Propylene is polymerized in a gaseous state. The latter two methods do not use diluents, have a short process and low energy consumption. The liquid-phase bulk method has now shown an advantage over the latter.

The synthesis of polyethylene can be divided into high-pressure polymerization, low-pressure polymerization and medium-pressure polymerization according to its different polymerization pressures. In the production of polyethylene polymerization, all three methods are used, and their products are slightly different. Polyethylene polymerized by three methods has its own characteristics in structure, density and performance.

The high-pressure polymerization of polyethylene is polymerized at a high pressure of 100 300MPa with organic peroxide as the initiator, and this polyethylene can also be called high-pressure polyethylene. Its density is within the range, if classified by density, it is called low-density polyethylene.

The low-pressure polymerization of polyethylene is based on a Ziegler catalyst (organometall) or metal oxide as a catalyst, so ethylene can be polymerized into polyethylene under low-pressure conditions, so it was also called low-pressure polyethylene in the past. The density of polyethylene polymerized by low-pressure method is, compared with the polyethylene polymerized by high-pressure method, the polyethylene synthesized by low-pressure method not only has a higher density value, but also its tensile strength and tear strength are higher than that of polyethylene produced by high-pressure method. Because of its high density value, it is also called high-density polyethylene.

The polymerization temperature and pressure of the medium-pressure polyethylene are higher than those of the low-pressure polyethylene. The macromolecular structure of medium-pressure polyethylene is linear, and its purity and performance are between high-pressure polyethylene and low-pressure polyethylene in many aspects. Therefore, the polyethylene produced by this method is called medium density polyethylene, and MDPE is the abbreviation code of medium density polyethylene.

In addition, there is a principle of adding nucleating agent and heterogeneous nucleation to produce polyethylene.

Answer]: Polypropylene ingenuity copy production method of liquid calling:

1. Slurry method. Polymerization in diluents (such as hexane) is the earliest industrialized and the largest production method of Xiaolianbi.

2. Liquid phase bulk method. Polymerization in liquid propylene at 70 and 3 MPa.

3. Gas phase method. Propylene is polymerized in a gaseous state. The latter two methods do not use diluents, have a short process and low energy consumption. The liquid-phase bulk method has now shown an advantage over the latter.

Summary. Hello, propylene is one of the main raw materials for polyethylene production. Polyethylene is a widely used plastic that is used to make a variety of products such as plastic bags, bottles, pipes, and insulation, among others.

Therefore, propylene production plays an important role in the development of the polyethylene plastic industry. <>

Hello, propylene is one of the main raw materials for polyethylene production. Polyethylene is a widely used plastic that is used to make a variety of products such as plastic bags, bottles, pipes, and insulation, among others. Therefore, propylene production plays an important role in the development of the polyethylene plastic industry.

Propylene can be added to polyethylene as a refiller to improve the properties of polyethylene. In this way, the properties of the polyethylene can be adjusted, such as strength and softness. In addition, propylene is also used to produce polypropylene, another widely used plastic. <>