General Plastics There are five varieties of general plastics, namely polyethylene, polypropylene, polyvinyl chloride, polystyrene and ABS. They are all thermoplastics.
Polyethylene (PE)
Polyethylene is the most productive variety in the plastics industry. Polyethylene is an opaque or translucent, light-weight crystalline plastic, with excellent low temperature resistance (minimum use temperature can reach -70 ~ -100 ℃), electrical insulation, good chemical stability, acid, alkali and salt resistance Corrosion similar to aqueous solution, but not suitable for wiping or soaking with strong alkaline detergent, because it is not heat resistant. Polyethylene is suitable for processing by injection molding, blow molding, extrusion molding and other methods. According to different density, PE can be divided into: low density polyethylene LDPE; high density polyethylene HDPE; linear low density polyethylene LLDPE. Polyethylene is usually used to make food bags and various containers.
Polypropylene (PP)
Polypropylene is a thermoplastic obtained by polymerization of propylene. It is usually a colorless, translucent solid, odorless and non-toxic, with a density of 0.90 ~ 0.919 g/cm. It is the lightest general-purpose plastic. Its outstanding advantage is that it has resistance to water. The characteristics of cooking, can be immersed in boiling water at 100 ℃, no deformation, no damage, corrosion resistance, common acid and alkali organic solvents have almost no effect on it, strength, rigidity and transparency are better than polyethylene, the disadvantage is resistance Low-temperature impact is poor and easy to age, but it can be improved by modification and addition of additives. There are three methods for producing polypropylene: slurry method, liquid phase bulk method and gas phase method. Polypropylene is mostly used for food utensils.
Polyvinyl Chloride (PVC)
Polyvinyl chloride is a plastic made by the polymerization of vinyl chloride. It has bright color, corrosion resistance, durability, and its hardness can be greatly changed by adding plasticizers. The production methods of polyvinyl chloride include suspension polymerization, emulsion polymerization and bulk polymerization, with suspension polymerization being the main method. Due to the addition of some toxic auxiliary materials such as plasticizers and anti-aging agents in the manufacturing process, the products generally do not store food and drugs.
Polystyrene (PS)
General-purpose polystyrene is a polymer of styrene, which is easy to color and has good transparency, but has the disadvantage of being brittle. Therefore, by adding polybutadiene, it can be made into impact-resistant polystyrene (HTPS). It is resistant to acid and alkali corrosion, but is easily soluble in organic solvents such as chloroform, dichloroethylene and banana water. The main production methods of polystyrene are bulk polymerization, suspension polymerization and solution polymerization. Polystyrene is mostly used to make lampshades, toothbrush handles, toys, and electrical parts.
ABS
ABS resin is the product of the co-polymerization of acrylonitrile-butadiene-styrene three monomers, referred to as ABS terpolymer. This plastic has very different properties due to the different proportions of its components A (acrylonitrile), B (butadiene) and S (styrene) in composition and the difference in manufacturing methods. ABS is suitable for injection molding and extrusion processing, so its use is mainly to produce these two types of products. The color of ABS resin is eye-catching, heat-resistant, strong, and the outer surface can be plated with metal films such as chrome and nickel. It can be used to make piano keys, buttons, knife holders, TV casings, umbrella handles, etc.
