Polyphenylene sulfide (PPS), also known as polyphenyl sulfide, is a thermoplastic resin with a benzene sulfide group in the main molecular chain. It is a special engineering plastic with excellent comprehensive performance and is widely used in fields such as electronics, electronics, machinery, aerospace, and chemical engineering.

Characteristics of PPS

1 General performance

PPS is a polymer with a white appearance, high crystallinity, and hardness and brittleness. The density of pure PPS is 1.35g/cm3, but it will increase after modification. PPS has a very low water absorption rate, usually only about 0.03%. PPS has good flame retardancy, with an oxygen index of over 44%, making it a high flame retardant material.

2 Mechanical properties

The mechanical properties of pure PPS are not high, especially the impact strength is low. After being reinforced with 40% glass fiber, the impact strength will be significantly increased from 27J/m to 76J/m, and the tensile strength will increase from 6MPa to 137MPa. PPS has high rigidity and is rare in engineering materials. The bending modulus of pure PPS can reach 3.8 GPa, and after inorganic filling modification, it can reach 12.6 GPa. The PPO known for its rigidity is only 2.55GPa, while the PC is only 2.1GPa. PPS has good creep resistance under load; High hardness; High wear resistance, with a wear loss of only 0.04g at 1000 rpm. Further improvement will be achieved after filling with PTFE and molybdenum disulfide; PPS also has a certain degree of self wetting. The mechanical properties of PPS are less sensitive to temperature.

3 Thermal performance

PPS has excellent thermal performance, can withstand 260 ℃ in the short term, and can be used for a long time at 200-240 ℃; Its heat resistance is equivalent to PI.

4 Electrical performance

PPS has outstanding electrical properties. Compared with other engineering materials, its dielectric constant and dielectric loss tangent value are relatively low, and it does not change much over a large frequency, temperature, and temperature range; PPS has good arc resistance, comparable to thermosetting plastics. PPS is commonly used as an electrical insulation material, which is also rare in thermosetting materials; Its dosage accounts for about 30%.

5 Environmental performance

One of the biggest characteristics of PPS is its good chemical corrosion resistance, which is second only to PTFE in chemical stability. PPS is stable for most acids, esters, ketones, phenols, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, and is not resistant to chlorinated biphenyls, oxidizing acids, oxidants, concentrated sulfuric acid, concentrated nitric acid, aqua regia, hydrogen peroxide, and sodium hypochlorite. PPS has good radiation resistance.

Modification of PPS

PPS has excellent comprehensive performance, but it also has the disadvantages of high brittleness, poor toughness, and low strength. Therefore, it is usually necessary to composite with other materials to improve performance, the most common being the addition of glass fiber and carbon fiber.

Glass fiber acts as a nucleating agent in the PPS matrix, causing PPS molecules to crystallize around the glass fiber, and then adding coupling agents to improve the interfacial adhesion between the two. When the composite material is subjected to external impact, it can play a reinforcing role.

Carbon fiber has the advantages of lightweight, high strength and modulus, conductivity and thermal conductivity, and low expansion coefficient. It is often used in the aerospace field through composite processing with PPS. This composite material is also considered one of the aviation thermoplastic composites with the best comprehensive performance and the most potential.

In addition, PPS can also be blended with PTFE to form composite materials. The molecular structure of PTFE contains high bond energy carbon fluorine bonds, and the shielding effect formed by fluorine atoms outside the carbon chain makes it have excellent self-lubrication, electrical insulation, chemical stability, high and low temperature resistance, aging resistance, and other advantages. Combining with PPS can not only leverage the advantages of both, but also improve the disadvantages of poor toughness, low mechanical strength, and low wear resistance of PPS. The combination of the two can be described as a 'perfect match'.

application area

Electronic and electrical: High voltage components, casings, sockets, terminals on televisions and computers, starting coils and blades of electric motors, brush brackets and rotor insulation components, contact switches, relays, electric irons, hair dryers, lamp holders, heaters, etc.

Automotive industry: suitable for exhaust gas recirculation valves and water pump impellers, as well as vaporizers, exhaust devices, exhaust control valves, light reflectors, bearings, sensing components, etc.

Machinery industry: used as bearings, pumps, valves, pistons, precision gears, as well as photocopiers, cameras, computer parts, conduits, spray, fuel nozzles, instrument parts, etc.

Chemical industry: Used for producing corrosion-resistant components such as acid and alkali resistant valves, pipes, fittings, valves, gaskets, and submersible pumps or impellers.

Environmental protection field: PPS fiber filter material is used in industries such as smelting, chemical engineering, building materials, thermal power, garbage incinerators, coal-fired boilers, and other industries under high temperature and harsh working conditions. It is a high-quality, high-efficiency, and high-temperature resistant filter material.