PE is polyethylene.
PVC is polyvinyl chloride.
PP is polypropylene.
ABS is a polymer of acrylonitrile, butadiene and styrene.
PEP is a POlymer of polyethylene glycol PEG and propylene oxide po.
(1) polyvinyl chloride (PVC) is the most used plastic in buildings. The density of rigid PVC is 1.38 ~ 1.43g/cm3, with high mechanical strength and good chemical stability. The density of polyethylene (PE) and polypropylene (PP) is the smallest of all plastics, about 0.90. Polypropylene is usually used to produce building products, such as pipes and sanitary wares. (4) Polystyrene (PS) Polystyrene is a colorless and transparent glassy plastic. ⑤ABS plastic ABS plastic is a kind of modified polystyrene plastic, which consists of acrylonitrile (a), butadiene (b) and styrene (s).
polystyrene
It is a colorless and transparent plastic material. Its glass transition temperature is higher than 100 degrees Celsius, so it is often used to make various disposable containers that need to withstand the temperature of boiling water, namely disposable foam lunch boxes. Polypropylene: polypropylene
It is a semi-crystalline thermoplastic. High impact resistance, strong mechanical properties, resistance to various organic solvents and acid and alkali corrosion. It is widely used in industry and is one of the common polymer materials. Australian coins are also made of polypropylene. Polyethylene: polyethylene
It is one of the most commonly used polymer materials in daily life, and is widely used to make plastic bags, plastic films, milk barrels and so on.
Polyethylene is resistant to all kinds of organic solvents, acids and bases, but not to oxidizing acids, such as nitric acid. Polyethylene will be oxidized in an oxidizing environment.
Polyethylene can be regarded as transparent in the film state, but when it exists as a block, it will be opaque because of strong light scattering because there are a lot of crystals in it. The crystallinity of polyethylene is affected by the number of branches. The more branches there are, the more difficult it is to crystallize. The melting temperature of polyethylene crystals is also affected by the number of branches, ranging from 90 degrees Celsius to 130 degrees Celsius. The more branches, the lower the melting temperature. Polyethylene single crystals can usually be prepared by dissolving high-density polyethylene in xylene at an environment higher than 130 degrees Celsius. ABS: It is a synthetic plastic of acrylonitrile, butadiene and styrene.
Graft polymerization products of acrylonitrile, butadiene and styrene are named after their initials. It is a kind of resin with high strength, good toughness and excellent comprehensive performance, which is widely used and often used as engineering plastics. In industry, polybutadiene latex or styrene-butadiene rubber with low styrene content is the main chain, and it is obtained by graft polymerization with a mixture of acrylonitrile and styrene. In fact, it is often a mixture of graft polymers containing butadiene and acrylonitrile-styrene polymers. In recent years, styrene and acrylonitrile were polymerized first, and then mixed with ABS resin grafted with styrene and acrylonitrile in different proportions to prepare various ABS resins suitable for different purposes. In the mid-1950s, the United States began industrialized production.
Industrial production methods can be divided into two categories: one is to mechanically mix polybutadiene or styrene-butadiene rubber with SAN resin on a roller, or to polymerize after mixing two kinds of latex; The other is that styrene and acrylonitrile monomers are added to polybutadiene or styrene-butadiene latex with low styrene content for emulsion graft copolymerization, or mixed with SAN resin in different proportions.
Structure, properties and application in ABS resin, rubber particles are dispersed in the continuous phase of SAN resin. When impacted, the crosslinked rubber particles bear and absorb this energy, which disperses the stress, thus preventing the crack from developing and improving the tear resistance.
The purpose of graft polymerization is to improve the compatibility and adhesion between rubber particle surface and resin phase. This is related to the amount of free SAN resin and the composition of SAN resin grafted on the rubber backbone. The difference of acrylonitrile content between the two resins should not be too big, otherwise the compatibility is not good, which will lead to the interface cracking between rubber and resin.
ABS resin can be processed into plastic by injection molding, extrusion, vacuum, blow molding, calendering and other methods, and can also be processed by mechanical, adhesive, coating, vacuum steaming and other methods. Because of its excellent comprehensive performance and wide application, it is mainly used as engineering materials and household appliances. Because of its good oil resistance, acid resistance, alkali resistance, salt resistance and chemical reagent resistance, as well as its electroplating property, the plated metal layer has the advantages of good luster, light specific gravity and low price, and can be used to replace some metals. It can also be synthesized into self-extinguishing, heat-resistant and other varieties to adapt to various uses. PET: polyethylene terephthalate
Terephthalic acid, a polymer containing ethylene glycol, is abbreviated as PET, which is mainly used to make polyethylene terephthalate fibers. China's trademark is polyester. This kind of fiber has high strength and good wearability. At present, it is one of the most productive synthetic fibers. 1980 The world output was about 565,438+ten thousand tons, accounting for 49% of the world's total synthetic fiber output.
The high symmetry of molecular structure and the rigidity of p-phenylene chain make the polymer have the characteristics of high crystallinity, high melting temperature and insolubility in general organic solvents, and the melting temperature is 257 ~ 265℃. Its density increases with the increase of crystallinity. The density of amorphous fiber is 65438 0.33 g/cm3. After stretching, due to the increase of crystallinity, the fiber density is1.38 ~1.41g/cm3. According to the X-ray study, the density of the complete crystal is 65438+. The glass transition temperature of amorphous polymer is 67℃; The crystalline polymer is 865438 0℃. The heat of fusion of the polymer is113 ~122 j/g, the specific heat capacity is1~1.4 j/g, the dielectric constant is 3.0 ~ 3.8, and the resistivity is/kloc. PET is insoluble in common solvents, but only soluble in some highly corrosive organic solvents, such as mixed solvents of phenol, o-chlorophenol, m-cresol and trifluoroacetic acid. PET fiber is stable to weak acids and bases.
Uses are mainly used as raw materials for synthetic fibers. Short fibers can be blended with cotton, wool and hemp to make textiles for clothing or cloth for indoor decoration; Filament can be used as clothing yarn or industrial yarn, such as filter cloth, tire cord, parachute, conveyor belt, safety belt and so on. Film can be used as the base of photosensitive film and recording tape. Injection molded parts can be used as packaging containers. PVC: polyvinyl chloride
It is a polymer material, which uses chlorine atoms to replace hydrogen atoms in polyethylene.
The biggest feature of PVC is flame retardant, so it is widely used in fire protection applications. However, PVC will release toxic gases such as hydrochloric acid during combustion. polyformaldehyde
The scientific name is polyoxymethylene, which is a thermoplastic crystalline polymer. The English abbreviation is POM. The structural formula is CH-O. Before 1942, the products obtained by formaldehyde polymerization were mostly polyoxymethylene ethylene glycol Hoch-o-h, with low degree of polymerization and easy depolymerization when heated, in which paraformaldehyde with = 8 ~100; More than 100 is-polyformaldehyde, about 1955. DuPont Company of the United States polymerizes formaldehyde to obtain formaldehyde homopolymer, that is, homopolyformaldehyde, with the trade name Delrin. Celanese Company of the United States prepared a * * * polymer containing a small amount of dioxolane or ethylene oxide, namely * * * polyoxymethylene, with the trade name Celcon.
Polyformaldehyde is easy to crystallize, and the crystallinity reaches 70%. By high temperature annealing, the crystallinity can be increased. The melting temperature of paraformaldehyde is 18 1℃, and the density is 1.425 g/cm. * * * The melting point of polyoxymethylene is about 170℃. The glass transition temperature of paraformaldehyde is -60℃. Phenolic compounds are the best solvents for polyoxymethylene. According to the study of melting index, the molecular weight distribution of paraformaldehyde is narrow. Paraformaldehyde is stable to other chemical reagents except strong acid, oxidant and phenol, while paraformaldehyde is unstable to concentrated ammonia water. Stable polyoxymethylene can be heated to 230℃ without obvious decomposition. Polyformaldehyde can be molded by compression, injection, extrusion and blow molding, and the processing temperature is 170 ~ 200℃. It can also be machined and welded by machine tools. Light weight, good hardness, rigidity and elasticity, stable size, low friction coefficient, low water absorption, good insulation performance and resistance to organic solvents; It can be used in a wide temperature range and humidity range of -50 ~ 105℃; Under the action of various solvents and chemical reagents, the performance remains unchanged under heavy load and long-term cyclic stress.