Polyvinyl chloride PVC is slightly yellow in color, translucent and shiny. The transparency is better than polyethylene and polystyrene, but worse than polystyrene. Depending on the amount of additives, it is divided into soft and hard polyvinyl chloride. Soft products are flexible and tough and feel sticky, while hard products have a higher hardness than low-density polyethylene. , and lower than polypropylene, whitening will occur at the inflection point. Common products: sheets, pipes, shoe soles, toys, doors and windows, wire sheaths, stationery, etc. Polyvinyl chloride is a polymer material that uses a chlorine atom to replace a hydrogen atom in polyethylene. Several main abbreviations and meanings of PVC 1. In the chemical industry, it refers to the compound polyvinyl chloride. polyvinyl chloride. This is the most widely used meaning of PVC. 2. Medically speaking, it refers to irregular heartbeat. premature ventricular contraction 3. In the electronic field, it refers to the persistent virtual link in ATM and X.25. permanent virtual circuit[Edit this paragraph]English name Polyvinyl chloride polymer = PVC[Edit this paragraph]Simple structural formula The structure of this material is as follows - CH2 - CHCl - CH2 - CHCl - CH2 - CHCl -[Edit this paragraph] Material properties Polyvinyl chloride: Density: 1380 kg/m3; Young’s modulus of elasticity (E): 2900-3400 MPa; Tensile strength (σt): 50-80 MPa; Elongation @ break 20-40%; Notch test 2-5 kJ/m2; Glass transition temperature: 87 °C; Melting point 212 °C | Vicat B1 85 °C | Thermal conductivity (λ) 0.16 W/m.K | Thermal expansion coefficient (α) 8 10-5 /K | Heat capacity (c) 0.9 kJ/(kg·K) Water absorption (ASTM) 0.04-0.4 | Price 0.5-1.25?/kg The biggest feature of polyvinyl chloride is flame retardancy, so it is widely used in fire protection applications. But PVC releases hydrogen chloride and other toxic gases, such as dioxins, during the combustion process. The combustion of polyvinyl chloride is divided into two steps. First, hydrogen chloride gas and dienes containing double bonds are decomposed by combustion at 240°C-340°C, and then carbon combustion occurs at 400-470°C. Stable physical and chemical properties; not easily corroded by acids and alkali; relatively resistant to heat. PVC is flame retardant (flame retardant value is above 40) and has high chemical resistance (resistant to concentrated hydrochloric acid and 90% sulfuric acid) , nitric acid with a concentration of 60% and sodium hydroxide with a concentration of 20%), has the advantages of good mechanical strength and electrical insulation. However, its heat resistance is poor, its softening point is 80°C, and it begins to decompose and change color at 130°C, and precipitates HCI. Industrial polyvinyl chloride resin is mainly amorphous structure, but also contains some crystalline areas (about 5%), so polyvinyl chloride has no obvious melting point and begins to soften at about 80°C. Thermal distortion temperature (under load of 1.82MPa ) is 70-71°C. It begins to flow at 150°C under pressure and begins to slowly release hydrogen chloride, causing the polyvinyl chloride to change color (from yellow to red, brown, or even black). The weight average relative molecular mass of industrial polyvinyl chloride is in the range of 48,000-48,000, and the corresponding number average relative molecular mass is 20,000-19,500. The weight average relative molecular mass of most industrial resins is between 100,000 and 200,000, and the number average relative molecular mass is between 45,500 and 64,000. Rigid polyvinyl chloride (without plasticizer) has good mechanical strength, weather resistance and Due to its flame resistance, it can be used alone as a structural material and used in the chemical industry to manufacture pipes, plates and injection molded products. Rigid polyvinyl chloride can be reinforced with materials [edit this paragraph] Development History In 1912, the German Fritz Klatte synthesized PVC and applied for a patent in Germany, but was unable to develop a suitable product before the patent expired. In 1926, Waldo Semon of the B.F. Goodrich Company in the United States synthesized PVC and applied for a patent in the United States. [Edit this paragraph] Scope of application: Due to its fireproof and heat-resistant effect, polyvinyl chloride is widely used in wire sheaths and optical fiber sheaths. In addition, it is often made into gloves and plastic wrap for certain foods. Polyvinyl chloride can be made from ethylene, chlorine and catalysts.

Recycling and recycling resources: International plastic recycling code: PVC is 3 (the word 3 is in the center of the three recycling arrows). This must be listed on the bottom of the plastic body or on the packaging for the convenience of consumers and recyclers. Can be classified appropriately. Polyethylene waste Polyethylene is a thermoplastic with the largest output among plastics and a wide range of uses. It is polymerized from ethylene and is a partially crystalline material that can be processed by the molding methods of general thermoplastics. Polyethylene can be divided into three categories: high-density polyethylene, low-density polyethylene and linear low-density polyethylene. The density of high-density polyethylene is generally higher than 0.94g/cm, while the density of low-density polyethylene and linear low-density polyethylene is between 0.91 and 0.94g/cm. There are two main sources of waste polyethylene film: 1. Leftovers, defective products, etc. generated in film production. These waste materials are clean and have clear varieties. They can be crushed and compressed and sent directly to the extruder for granulation. The recycling process is relatively simple. 2. Waste films from the chemical industry, electrical industry, food and consumer goods industry, etc. These waste films have been contaminated, some have been colored and printed with trademarks, and some also contain impurities such as sand, sawdust or shredded paper. Because polyethylene is cheap, easy to obtain, and easy to mold, its products have a wide range of applications, but the most used ones are packaging products, estimated at more than 60%. High-density polyethylene is mainly used in packaging films, bottles, and hollow containers; low-density polyethylene is mainly used in packaging films and agricultural films; linear low-density polyethylene is mainly used in films, film plastics, and pipes. And on wires and cables. Polyvinyl chloride waste PVC used to be the most widely used plastic in history. Now it is replaced by polyethylene and PET in some fields, but it is still used in large quantities. Its consumption is second only to polyethylene and polypropylene. Polyvinyl chloride products are available in various forms and can be divided into three categories: hard polyvinyl chloride, soft polyvinyl chloride, and polyvinyl chloride paste. Rigid polyvinyl chloride is mainly used in extruded products such as pipes, door and window profiles, and sheets, as well as injection molded parts such as pipe joints and electrical parts, and extrusion-blown bottle products. They account for more than 65% of PVC consumption. Soft PVC is mainly used in calendered sheets, automotive interiors, handbags, films, labels, wires and cables, medical products, etc. PVC paste accounts for about 10% of PVC products, and its main products include slush molding products.