Plastic Raw Material Plastic Raw Material Plastic Raw Material Plastic Raw Material
Pps (polyphenylene sulfide) is a thermoplastic engineering plastic containing benzene sulfide group on the molecular backbone, which belongs to polyether plastics. It was industrially produced in the United States in 1968. The main production methods in the industry are solution polymerization and self-condensation polymerization. It can be seen from the molecular structure of PPS that it is a polymer with linear or slightly branched chains composed of benzene ring and sulfur atoms arranged alternately. The molecular chain has strong integrity, and the main bond connected by rigid benzene ring and flexible sulfur  ether chain has the characteristics of rigidity and flexibility, so PPS can be crystallized with high melting point. Secondly, since the benzene ring forms a conjugate with the sulfur atom. And the sulfur atom is not yet saturated, after oxidation, the thioether bond can be turned into a sulfoxide group, or the adjacent macromolecules can form oxygen bridge branching or cross-linking, which makes the thermal and oxygen stability very prominent. Thirdly, the polarity of sulfur atoms is bound by benzene ring conjugation and high crystallinity, which makes PPS show the characteristics of non-polarity or weak polarity, so the electrical insulation, dielectric and chemical resistance of PPS are also very prominent. Fourth, because PPS has good compatibility with many polymers and additives, it can be modified by various means to improve its mechanical and other properties.
Characteristics of PPS plastic raw materials:
(1) Common characteristics of PPS plastic raw materials
PPS is a white powder with an average molecular weight of 0.4-0.5 thousand and a density of 1.3-1.8 grams per cubic centimeter. PPS has very interesting thermal properties. Its maximum continuous use temperature is 400 degrees. PPS has excellent thermal stability. The weight loss is not obvious when heated to 500 degrees, and it will be completely degraded when heated to 700 degrees. Its flexural strength and tensile strength can also maintain more than 50%. The tensile strength, bending strength and other properties of PPS are at a medium level in engineering plastics, while the elongation and impact strength are very low. Therefore, additives such as glass fiber, carbon fiber and filler are usually added to enhance the mechanical properties of PPS. After this modification, the main mechanical properties of PPS are: For example, the tensile properties, flexural properties, compression and impact strength have been greatly improved, while the elongation rate has decreased. The modified PPS can maintain high mechanical properties and dimensional stability under long-term load and thermal load, so it can be applied to high temperature stress environment.
PPS dielectric constant is small, a low dielectric loss, surface resistivity and volume resistivity is not sensitive to the change of frequency, temperature, humidity, is a good electrical insulating material, its electrical resistance fox time is longer, the chemical stability of PPS is pretty good, in addition to the strong oxidizing acids, such as sulfuric acid, nitric acid and aqua regia erosion, it is not affected by the vast majority of acid and alkali salt erosion, The chemical stability is close to PTFE. It is not soluble in any known organic solvent at less than 175 degrees, and PPS will not crack in contact with general organic solvents.
Because the molecular chain of PPS is composed of benzene ring and sulfur atoms arranged alternately, it has a flame retardant effect, and can reach the level of UL-94-VO without adding flame retardant. Its limiting oxygen index can reach 44%-53%, which is similar to PVC. It is a kind of self-quenching plastic. PPS is also stable to ultraviolet rays and rays, and will not be sticky or decomposed on the surface when irradiated.
The main shortcomings of PPS are poor toughness, low impact strength, and unstable melt viscosity.
Main uses of PPS
Main uses of PPS
The application of PPS is based on its excellent heat resistance as the center, taking into account its anti-friction self-lubricity, chemical stability, dimensional stability, flame retardant and electrical insulation. In the chemical industry, PPS can be used as reaction tanks, pipelines, valves and chemical pumps for synthesis, transportation and storage of materials. In the mechanical center, PPS can make impeller, blade, gear, eccentric wheel, bearing, clutch and wear-resistant parts. PPS is mainly used in the field of electronic and electrical appliances, such as the production of transformer skeletons, high-frequency coil skeletons, plugs, sockets, wiring racks, contactors, drums and various precision parts.
The material performance
1, electrical insulation (especially high frequency insulation) excellent, white hard and brittle? Falling on the ground has metal sound, light transmittance second only to organic glass, coloring water resistance, good chemical stability. Has excellent flame retardant property? Non-flammable plastic. 2, the intensity is general? The rigidity is very good, but the quality is brittle, easy to produce stress brittle crack, and not resistant to benzene. Gasoline and other organic solvents. Long-term use temperature up to 260 degrees? It remains stable in air or nitrogen at 400 degrees. By adding glass fiber or other reinforced materials modified? Can greatly improve the impact strength? Heat resistance and other mechanical properties are also improved. Density increase to 1.6-1.9? The molding shrinkage rate is small to 0.15-0.25% suitable for making heat resistant parts. Insulation parts and chemical instruments. Optical instruments and other parts. Molding performance 1. Amorphous material, moisture absorption is small, but should be dried after molding. 2. Mobility between ABS and PC? Solidification fast? Narrow closed? Easy to break down? Higher injection pressure and injection speed were selected. The mold temperature was taken from 100 to 150 degrees. Should the main channel taper be large? The flow channel should be short. The scope of application can be generally used in the manufacture of PPS tube, PPS plate and other materials. Mostly used in construction and household
Physical performance rating unit system test method
Density 1.68g /cm3 ISO 1183
Shrinkage rate – flow 0.40% ISO 294-4
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