Polyaryl ether nitrile (PEN) three-in-one filtration, washing and drying

Polyaryl ether nitrile (PEN) is a type of special engineering plastic with aryl ether structural units in the main chain of the macromolecule and strongly polar nitrile groups as side groups. It belongs to high-temperature resistant thermoplastics, featuring a relatively high glass transition temperature and melting point. Not only does it have superior heat resistance compared to other high-temperature resistant plastics, but it also possesses high strength, high modulus, high fracture toughness, and excellent dimensional stability. Polyarylether nitriles possess outstanding thermal stability, self-flame retardancy, high mechanical properties, good insulation, and resistance to chemical corrosion. They have broad application prospects and can be used in fields such as electronics and electrical appliances, mechanical manufacturing, automotive parts, and aerospace.

The traditional preparation process of polyarylether nitriles involves adding a catalyst and a dehydrating agent to a polar solvent (such as N-methylpyrrolidone (NMP)), followed by dehydration reaction, polymerization reaction and other steps to obtain high-molecular-weight polyarylether nitriles. There are many problems in the preparation methods of conventional polyarylether-nitrile plastics:

(1) Toluene, xylene and other benzene series substances need to be added as dehydrating agents to azeotrope with water to remove the water produced by the reaction, but the presence of benzene series substances will cause many problems.

(2) In the polymerization reaction stage of the traditional polyarylether nitrile preparation process, the system contains a large amount of salt, which increases the difficulty of the subsequent elution process.

(3) Due to the high content of benzene rings and rigid chain segments in the molecular structure of aromatic ether polymer polyarylether nitrile plastics, they are extremely difficult to dissolve in most organic solvents, making the separation and purification of high-molecular-weight polyarylether nitriles very difficult.

Analysis of a New Process for the Separation, Purification and Production of Polyarylethernitrile High-Performance Plastics

In response to the problems of the existing technology, the new process aims to address the issues such as environmental unfriendliness, difficult elution, increased equipment investment, and quality impact caused by the use of dehydrating agents and the presence of a large amount of salt in the polymerization system in the traditional process. The dedicated filtration, washing and drying integrated machine for high molecular plastics meets the requirements for the separation, purification and preparation of polyarylether-nitrile plastics.

(1) Polyaryl ether nitrile polymerization reaction

Potassium carbonate and 2, 6-dichlorobenzonitrile were successively added to N-methylpyrrolidone and stirred evenly to obtain the reaction solution. Diphenol and toluene were successively added to the reaction solution. Dehydration reaction was carried out first, followed by polymerization reaction to obtain a high-viscosity polyaryl ether nitrile solution.

(2) Polyaryl ether nitrile is cooled and crystallized

The high-viscosity polyarylethernitrile solution obtained from the polymerization reaction is introduced into an autoclave. The discharge port of this autoclave is equipped with a casting head, a pelletizing knife head and a cooling splash device. By starting the pelletizing knife head and the cooling splash device, the high-viscosity polyarylethernitrile solution is conveyed to the casting head at the discharge port under the action of a pressure pump. Polyarylethernitrile micro-particles are obtained successively through pelletizing and cooling by the cooling liquid.

(3) Grinding and crushing of polyaryl ether nitrile

The polyarylethernitrile micro-particles obtained through cooling and crystallization were ground and crushed together with the coolant to obtain polyarylethernitrile powder. Micro-particles are cylindrical particles with a length of 0.25 to 0.5mm and a diameter of 0.2 to 0.45mm.

(4) Polyaryl ether nitrile solvent extraction

The polyaryl ether nitrile powder obtained from grinding and crushing is conveyed to the special filtration, washing and drying integrated machine for high molecular plastics. This extraction equipment is equipped with a conical filter screen and an electric heating auxiliary device. The polyaryl ether nitrile powder is extracted and filtered by a mixed extraction solution of methanol and acetone. After 1 to 2 washes of the polyaryl ether nitrile powder, vacuum drying is carried out.

(5) Purification of polyaryl ether nitrile deionized water

Deionized water is added to the three-in-one cylinder cone filtration, washing and drying process. The polyarylether nitrile powder after solvent extraction and drying is washed with water and filtered. The polyarylether nitrile powder is eluted with deionized water 4 to 6 times, and finally dried to obtain the purified polyarylether nitrile polymer nitrile powder.

Advantages of the three-in-one technology of polyaryl ether nitrile (PEN) filtration, washing and drying

The Shuangrui brand integrated filtration, washing and drying machine is used for the improvement of the separation and purification process in the continuous production of polyarylether nitrile. It can solve the existing problems in the separation and purification of polyarylether nitrile production, ensure the continuity of polyarylether nitrile production, be environmentally friendly and have high production efficiency. Compared with the traditional separation and purification process of polyarylether nitriles, the new process solves the following three problems:

(1) After the synthesis reaction is completed, there is no need to add a large amount of high-boiling-point solvent to dilute the reaction solution. This will not cause the synthesis reactor to occupy space and lead to production interruption, nor will there be a waste of resources due to the use of a large amount of solvent.

(2) During the separation and purification process, there is no longer a need to set up dedicated sedimentation tanks, simplifying the process equipment and procedures. In addition, there is no need for a large amount of precipitating agent to precipitate polyaryl ether nitrile particles, which will not cause waste of precipitating agents or increase the difficulty of recovering subsequent precipitating agents and other solvents.

Compared with the traditional extraction kettle, the new process designs a conical filter screen suitable for the particle size of this product and electric heating auxiliary equipment on the basis of the traditional extraction kettle, achieving the integration of multiple functions such as extraction, filtration and drying of the extraction kettle. There is no longer a need to set up pipelines to transport solid powder containing a certain amount of moisture, simplifying the design of pipelines and the process. Reduce the design cost of the process flow and eliminate potential safety hazards in the pipeline transportation link.

(4) The integrated filtration, washing and drying machine uses as little methanol as possible to effectively extract and purify the crude polyarylether nitrile. When the proportion is lower than this, the purification effect of the product cannot be achieved. When the proportion is higher than this, it is easy to cause the waste of methanol.

(5) The selection of the three-in-one filtration, washing and drying extraction temperature and extraction time is to ensure that the extraction and purification are thorough and complete. Any operation outside the parameter range will lead to poor purification effect or waste of resources.

The traditional separation and purification process design of polyarylether nitriles is unreasonable, and the steps are cumbersome and the efficiency is low. The integrated filtration, washing and drying machine of Wuxi Shuangrui simplifies the separation and purification production process of polyarylethernitrile high-performance plastics, ensures the continuity of production, has high efficiency, low energy consumption, is environmentally friendly and green, and is universal, meeting the requirements of large-scale industrial production processes.

Photo of the three-in-one equipment for filtration, washing and drying of polyaryl ether nitrile PEN

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