«PPS-1»: Synthesis of polyphenylene sulfide
TECHNOLOGY OF THE SYNTHESIS OF POLYPHENYLENE SULPHIDE
Polyphenylene sulfide (PPS, PPS) is a semi-crystalline engineering thermoplastic that is presented on the world market of superstructural materials in two modifications: the first is a cross-linked polymer, the second is a linear polymer with a highly ordered supramolecular structure.
Ideal for the production of complex extrusion profiles due to its strength characteristics. The material withstands high temperatures, pressure and exposure to aggressive chemicals. PPS complies with all required standards and specifications in these industries. Flame retardant by nature, UL94 class V-0.
Polyphenylene sulfide advantage is used as an alternative to plastics, metals, thermoplastics in the following areas:
– in mechanical engineering, aviation and automotive industries. The chemical resistance of the material ensures the possibility of contact of PPS products with fuels and lubricants, fuels, alkalis and acids without damage to these products;
– in the gas and oil industry, in the production of submersible pumps, products or parts operating in conditions of high humidity;
– in the field of electronics, electrical engineering, lighting engineering and so on. Super-rigidity, impact resistance, and dimensional stability make it possible to manufacture hollow products from PPS that are planned to be operated at elevated pressure: these are lamp sockets, lip seals, case products, structures with stiffeners.
Schematic diagram of obtaining PPS:
A sulfiding agent is prepared in the R-201 reactor: sodium sulfide is synthesized, and excess water is stripped off. In the R-201 reactor in the temperature range 200÷230℃ in the environment of n-methylpyrrolidone (NMP), the stage of preliminary polycondensation of paradichlorobenzene (p-DCB) and sodium sulfide takes place. The final polycondensation is carried out in the R-203 reactor in the temperature range 240÷270℃. Next, the synthesized PPS is filtered and washed in an F-201 filter. The washed PPS is unloaded and sent for drying.
The essence of the process:
Obtaining polyphenylene sulfides, according to the developed domestic technology, is carried out by nucleophilic polycondensation of p-dichlorobenzene with hydrosulfide sodium sulfide in a mixture with sodium hydroxide in an aprotic dipolar solvent medium.
Polycondensation is carried out at a temperature of 200÷270°C. N-methylpyrrolidone is used as a solvent.
Obtaining linear crystalline PPS with a degree of crystallinity of more than 80%.
Polyphenylene sulfides have improved physical and mechanical characteristics.