PPS board: China PPS board#High temperature resistance
PPS (polyphenylene sulfide) is a crystalline (crystallinity 55% - 65%) high rigid white powder polymer. It is a resin with high heat resistance (continuous service temperature up to 240 ℃), excellent mechanical strength, rigidity, flame retardancy, chemical resistance, electrical characteristics and dimensional stability. It has excellent wear resistance, creep resistance and flame retardancy. Self extinguishing, up to UL94V-0. It still maintains good electrical properties under high temperature and high humidity. Good fluidity, easy to form, and there are almost no shrinkage pits during forming. It has good affinity with various inorganic fillers. Its development shortens the difference between standard thermoplastic materials (such as PA, POM, pet...) and advanced engineering plastics.
Advantages: high mechanical strength. Rigid, excellent low wear, impact resistance and chemical resistance are better than PSU and PE. It meets the OSU standard and has very good chemical resistance and oxidation resistance. And hydrolysis resistance, which can be boiled by repeated steam. Fireproof self extinguishing plastic. At very high service temperature, it can still resist high corrosion and turbidity at 220 ℃ and can be used for a short time to 260 ℃. At this temperature, its flexural strength is similar to that of ABS in room humidity, with low shrinkage, excellent size and heat stability, which is undoubtedly used in physiology.
characteristic:
The allowable working temperature in the air is very high. It can work continuously at 220 ℃ and can reach 260 ℃ in a short time. It maintains high mechanical strength, stiffness and hardness in a high temperature environment, has excellent chemical corrosion resistance and hydrolysis resistance (no solvent that can dissolve polyphenylene sulfide below 200 ℃ has been found at present, and has strong resistance to inorganic acids, alkalis and salts), and has excellent wear resistance and friction resistance, Very good dimensional stability, excellent resistance to high-energy radiation, good UV resistance, flame retardancy and excellent electrical insulation.
(1) General properties: PPS is a white, high crystallinity, hard and brittle polymer. The relative {hottag} density of pure PPS is 1.3, but it will increase after modification. PPS has extremely low water absorption, generally only about 0.03%. PPS has good flame retardancy, and its oxygen index is more than 44%; Compared with other plastics, it is a high flame retardant material in plastics (oxygen index of pure PVC is 47%, PSF is 30%, PA66 is 29%, MPPO is 28%, PC is 25%).
(2) Mechanical properties: the mechanical properties of pure PPS are not high, especially the impact strength is relatively low. After reinforced with glass fiber, the impact strength and tensile strength will be greatly improved. The tensile strength > 170Mpa, bending strength > 220MPa and notch impact strength > 16MPa. PPS has high rigidity, which is rare in engineering plastics. The bending modulus of pure PPS can reach 3.8GPa and 12.6gpa after inorganic filling modification, which is increased by 5 times. PPO, which is famous for its rigidity, is only 2.55gpa and PC is only 2.1gpa. PPS has excellent creep resistance and fatigue resistance, and has good creep resistance under load. High surface hardness, Rockwell hardness > 100hr; The wear resistance is high, and the wear amount at 1000 revolutions is only 0.04g. By filling fluorine resin, molybdenum disulfide and other lubricants, the wear resistance can be greatly improved, and the friction coefficient is 0.01 ~ 0.02. PPS also has a certain self lubrication. The mechanical properties of PPS are less sensitive to temperature.
(3) Thermal properties: PPS has excellent thermal properties. Its melting point exceeds 280 ℃, thermal deformation temperature exceeds 260 ℃, short-term resistance is 260 ℃, and can be used for a long time at 200 ℃. It is degraded in air at 700 ℃, and the inert gas remains 40% by weight at 1000 ℃. After special modification, the thermal deformation temperature can reach more than 350 ℃.
(4) Electrical properties: PPS has outstanding electrical properties. Compared with other engineering plastics, its dielectric constant and dielectric loss tangent are relatively low, and it changes little in a large frequency, temperature and temperature range; PPS has good arc resistance, which is comparable to thermosetting plastics. PPS is commonly used in electrical insulation materials, and its dosage can account for about 30%.
(5) Chemical resistance: one of the characteristics of PPS is good chemical corrosion resistance, and its chemical stability is second only to F4; PPS is stable to most acids, esters, ketones, aldehydes, phenols, aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons. At present, no solvent that can dissolve polyphenylene sulfide below 200 ℃ has been found, and it has strong resistance to inorganic acids, bases and salts. It is not resistant to chlorinated biphenyls and oxidizing acids, oxidants, concentrated sulfuric acid, concentrated nitric acid, aqua regia, hydrogen peroxide and sodium hypochlorite.
(6) PPS has good radiation resistance and radiation resistance up to Gy 1 × 108 is a new material unmatched by other engineering plastics. It is an ideal excellent material for radiation resistance in electronic, electrical, mechanical, instrument, aviation, aerospace, military and other fields.
(7) Good dimensional stability: the molding shrinkage is very low, less than 0.0025%, the absorption is less than 0.05%, and the linear thermal expansion coefficient is also small. It still shows good dimensional stability under high temperature and high humidity. Therefore, it is widely used in machinery, chemical industry, instruments, instruments, aviation, aerospace, ships and other aspects.
(8) Excellent electrical properties: polyphenylene sulfide still has excellent electrical properties under high temperature, high humidity and high frequency conditions, and its volume resistivity is 1 × 1016 Ω. Cm, surface resistivity is 1 × 1015 Ω, electrical strength > 18kV / mm.
(9) It has flame retardancy: the flame retardancy of polyphenylene sulfide can reach ul94-0, and the oxygen index (LOI) > 57%. The chemical structure of polyphenylene sulfide makes it difficult to burn without adding flame retardant.
(10) Good adhesion with metal and non-metal: PPS has very high adhesion strength to glass, aluminum, titanium and stainless steel, and the adhesion force reaches grade 1. It has good adhesion to glass and is very suitable for lining chemical equipment.
(11) Good processability: PPS resin has low melt viscosity, good fluidity and easy contact with glass fiber. Therefore, it is easy to fill the filler. The glass fiber or inorganic filler prepared by PPS resin enhances the injection molding grade granular material, which has high elasticity, impact resistance, bending resistance and ductility. It can be formed uniformly above its melting point.
Application:
Electronic and electrical: micro electronic component packaging, coil framework, Mada shell, relay, fine tuning capacitor and other parts. Precision instruments: computers, timers, copiers, temperature sensors and shells and components of various measuring instruments.
Machinery: pump casing, pump wheel, valve, fan, flowmeter components, flange, universal head, etc. Automobile: igniter, clutch, transmission, gearbox, bearing support, exhaust system parts.
Household appliances: protective coatings and parts of hot air duct, hair curler, hair dryer, perm, rice cooker, etc.