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PPS is a white powder with an average molecular weight of 0.4-0.5 million and a density of 1.3-1.8 grams per cubic centimeter. PPS has significant thermal properties. The thermal performance index of PPS is higher after being reinforced with fiberglass, and its continuous use temperature peak can reach 400 degrees. PPS has excellent thermal stability, and the weight loss is not significant when heated to 500 degrees. It will only completely degrade at 700 degrees. Its mechanical properties decrease very little with the increase of temperature. After 5000 hours of thermal aging at 232 degrees, its bending strength and tensile strength can still be maintained at more than 50%. The tensile strength, bending strength, and other properties of PPS are at a moderate level in engineering plastics, while the elongation and impact strength are very low. Therefore, PPS is usually added with additives such as glass fiber, carbon fiber, fillers, etc. to enhance its mechanical properties in load-bearing components. After modification, PPS's main mechanical properties, such as tensile strength, bending strength, compression strength, and impact strength, are greatly improved, but the elongation rate decreases. The modified PPS can maintain high mechanical properties and dimensional stability under long-term and thermal loads, and can be applied to high-temperature load-bearing environments.
PPS has a very small dielectric constant and relatively low dielectric loss. Its surface resistivity and volume resistivity are not sensitive to changes in frequency, temperature, and humidity, making it an excellent electrical insulation material. Its electrical resistance time is also relatively long, and PPS has good chemical stability. In addition to being corroded by strong oxidizing acids such as concentrated sulfuric acid, concentrated nitric acid, and aqua regia, PPS is not corroded by the vast majority of acidic and alkaline salts, and has chemical stability close to PTFE. PPS is insoluble in any known organic solvents below 175 degrees Celsius, and there will be no cracking of plastic parts when in contact with general organic solvents.
Due to the alternating arrangement of benzene rings and sulfur atoms in the molecular chain of PPS, it has flame retardant properties and can reach UL-94-VO level without the need for flame retardants. Its ultimate oxygen index can reach 44% -53%, similar to PVC, and it is a self extinguishing plastic. PPS is also very stable to ultraviolet, radiation, etc., and will not cause surface sticking or decomposition when irradiated.
The main shortcomings of PPS are poor toughness, low impact strength, and unstable melt viscosity.