Polyphenylene sulfide (PPS) is a high-performance thermoplastic engineering plastics, with high temperature resistance, chemical resistance, high mechanical strength, excellent electrical properties, etc., widely used in chemical, electronics, machinery, automotive, aerospace and other fields. In the field of raw materials for chemical production, there are several manufacturing methods for polyphenylene sulfide:
I. Melt Condensation Method
Melt condensation method is a method to produce polyphenylene sulfide by polycondensation reaction between hydroquinone (HQ) and thiodiphenyl ether (SDE) in molten state. The reaction temperature of this method is high and needs to be carried out at high temperature, but no solvent is needed in the reaction process, so it has the advantages of simple process and low cost. The specific steps are as follows:
1. mix hydroquinone and thiodiphenyl ether in accordance with a certain molar ratio;
2. heat the mixture to a molten state, and carry out the polycondensation reaction;
3. remove the low molecular by-products and un-reacted monomers under the vacuum condition;
4. cool, cut the granules, and get the polyphenylene sulfide products.
II. Solution polycondensation method
Solution polycondensation method is the method to produce polyphenylene sulfide by polycondensation reaction between hydroquinone and thiodiphenyl ether in solvent. Compared with the melt polycondensation method, the solution polycondensation method has a lower reaction temperature and can be carried out under milder conditions, but it requires the use of a large number of solvents, so the cost is higher. The specific steps are as follows:
1. dissolve hydroquinone and thiodiphenyl ether in the solvent according to a certain molar ratio;
2. carry out the polycondensation reaction under a certain temperature and pressure;
3. remove the solvent and the low molecular by-products by distillation and other methods;
4. obtain the polymer solution of polyphenylene sulfide, and obtain the product of polyphenylene sulfide after precipitation, washing, drying and other steps.
Third, solid-phase polymerization method
Solid-phase polymerization method is a method to generate polyphenylene sulfide by polycondensation reaction of solid mixture of hydroquinone and thiodiphenyl ether at high temperature. The method requires no solvent and has the advantages of simple process and low cost, but the reaction time is longer and a higher reaction temperature is required. The specific steps are as follows:
1. mixing hydroquinone and thiodiphenyl ether homogeneously in accordance with a certain molar ratio;
2. carrying out a solid-phase condensation reaction of the mixture at a high temperature;
3. obtaining a polyphenylene sulfide product by grinding, sieving and other methods.
In summary, the melt polycondensation method, the solution polycondensation method and the solid-phase polycondensation method are all methods for manufacturing polyphenylene sulfide, and each method has its advantages and disadvantages and scope of application. In actual production, the suitable method can be selected according to the specific situation and demand.
