What are Engineering Plastics? What are its performance characteristics?

Global PlasticizationThink engineering plastics.

It refers to industrial plastics that are used as industrial parts or shell materials, and are plastics with excellent strength, impact resistance, heat resistance, hardness and aging resistance. In Japan, it is defined as a high-performance plastic that can be used for construction and mechanical parts, with a heat resistance of more than 100 degrees, and is mainly used in industry.

The performance characteristics of engineering plastics are mainly as follows:

Compared with general-purpose plastics, it has excellent heat and cold resistance, and mechanical properties in a wide range of temperatures.

Excellent, suitable for use as a structural material;

Good corrosion resistance, less environmental influence, good durability;

Compared with metal materials, it is easy to process, has high production efficiency, and can simplify the procedure and save costs;

It has good dimensional stability and electrical insulation;

Light weight, specific strength.

high, and has outstanding anti-friction, wear resistance.

The world's five major engineering plastics are polyamide (PA), polycarbonate (PC), polyoxymethylene (POM), polyphenylene ether (PPO) and thermoplastic polyester (PBT).Engineering plastics can be divided into two categories: general engineering plastics and special engineering plastics. The main varieties of the former are polyamide, polycarbonate, polyoxymethylene, modified polyphenylene ether and thermoplastic polyester five general engineering plastics; The latter mainly refers to engineering plastics with a heat resistance of more than 150, and the main varieties are polyimide.

Polyphenylene sulfides, polysulfones, aromatic polyamides, polyaryl esters, polyphenyl esters, polyaryletherketone, liquid crystal polymers and fluororesins, etc.

The performance characteristics of engineering plastics are mainly as follows: (1) Compared with general-purpose plastics, they have excellent heat and cold resistance, excellent mechanical properties in a wide range of temperatures, and are suitable for use as structural materials; (2) Good corrosion resistance, less environmental impact, good durability; (3) Compared with metal materials, it is easy to process, has high production efficiency, and can simplify the procedure and save costs; (4) Good dimensional stability and electrical insulation; (5) Light weight, high specific strength, and outstanding friction reduction and wear resistance. Through modification, it can also achieve better comprehensive performance.

Engineering plastics refer to plastics that are used as structural materials in engineering, and this kind of plastic generally has high mechanical strength, or has good properties such as high temperature resistance, corrosion resistance, and limb abrasion resistance, so it can replace metal to make some mechanical parts.

Table: Properties and applications of engineering thermoplastics.

Table: Properties and applications of commonly used engineering thermoplastics.

Answer]: Engineering plastics refer to plastics that can withstand certain external forces, have good comprehensive properties such as punching and retardation resistance, pre-belt heat resistance, hardness and aging resistance, etc., and have certain metal characteristics and can be used instead of metal in mechanical equipment and engineering structures. For example, polyoxymethylene, ABS resin, polycarbonate, PTFE, etc.

Commonly used plastics in construction are:

1) Polyethylene plastic Polyethylene plastic is polymerized from polyethylene resin, which is a white translucent material with excellent electrical insulation properties and chemical stability. However, the mechanical strength is not high, the texture is more flexible, and it is not resistant to high temperatures. In construction, it is mainly used to make pipes or tanks for discharging or storing cold water; It is made into a film for moisture-proof, waterproof engineering, or as an insulating material.

2) Polyvinyl chloride plastic Polyvinyl chloride plastic is a general-purpose plastic, which is made of polyvinyl chloride resin with plasticizers, fillers, pigments and other additives to make various colors of translucent and opaque plastics. According to the addition of different amounts of plasticizers, hard or soft products can be prepared. It can be used in a temperature range of:

15 55, good chemical stability, can resist the corrosion of acid and alkali salts, and wear resistance, with silencing, shock absorption function, its bending strength is greater than 60MPa.

3) Phenolic plastic Phenolic resin plastic is a combination of phenols and aldehydes, with two types of thermoplastic and thermosetting, with heat resistance, moisture resistance, chemical attack resistance and electrical insulation and other properties. The color is brown and black, but it is brittle and not resistant to impact. It is mainly used as bakelite powder, glass fiber reinforced plastic, laminate, etc. in construction projects.

4) Polymethyl methacrylate plastic polymethyl acrylate is formed by the reaction and polymerization of acetone, cyanide and methanol. The plastic made without other components has a high degree of transparency, and is made into a flat plate or corrugated board (also known as plexiglass) for lighting on the building, and a sail slippery pigment state front, dyes, stabilizers and fillers are added to the resin, which can be extruded or molded into building products with a smooth surface, and the resin reinforced with glass fiber can be made into bathtubs and other sanitary products.

1. Light weight and easy to transport. Compared with steel and wood, plastic is lighter and more convenient to transport, especially polypropylene plastic, which has a density of only 0 90--0.

At 91g cm3, it is the lightest dense plastic, so among the tube materials, the construction industry usually chooses lightweight plastics instead of heavier steel materials.

2. Strong plasticity. The plastic will melt after being heated, and the melted material will be put into the mold, and after cooling and solidification, different plastic parts will be obtained, but its sensitivity to temperature is strong, so if the material acts in a high temperature environment, relevant additives should be added to prolong the service life.

3. Corrosion-resistant and wear-resistant. Most of the plastic materials are corrosion-resistant and insoluble in weak acids and alkalis, but some materials are more sensitive to water and easy to absorb water, such as PET materials, which often need to be dried before processing, and will be modified in practical applications.

Polyamide, polycarbonate, polyoxymethylene, ABS resin, and polytetrafluoroethylene are divided into general plastics and engineering plastics according to the different uses of plastics.

General plastics refer to plastics with large output, low production and wide range of applications, mainly including five varieties of polyolefin, polyvinyl chloride, polystyrene, phenolic plastics and amino plastics. Many of the products that people use in their daily lives are made from these general-purpose plastics.

Engineering plastics are plastics that can be used as engineering structural materials and as a substitute for metal manufacturing machine parts. Such as polyamide, polycarbonate, polyoxymethylene, ABS resin, PTFE, polyester, polysulfone, polyimide, etc. Engineering plastics have the characteristics of low density, high chemical stability, good mechanical properties, superior electrical insulation, easy processing and molding, etc., and are widely used in automobiles, electrical appliances, chemical industries, machinery, instruments, meters and other industries, and are also used in aerospace, rockets, missiles, etc.

The properties of plastics are:

1. Most plastics are lightweight, chemically stable, and will not corrode;

2. Good impact resistance;

3. It has good transparency and wear resistance;

4. Good insulation, low thermal conductivity;

5. Good general formability and colorability, low processing cost;

6. Most plastics have poor heat resistance, large thermal expansion rate and are flammable;

7. Poor dimensional stability, easy to change the shape of the belt.

1. Most plastics are lightweight, chemically stable, and will not corrode; 2. Good impact resistance; 3. It has good transparency and wear resistance; 4. Good insulation, low thermal conductivity; 5. Good general formability and colorability, low processing cost; 6. Most of the plastics have poor heat resistance, large thermal expansion rate, and are flammable; 7. Poor dimensional stability and easy deformation; 8. Most plastics have poor low temperature resistance and become brittle at low temperatures; 9. Tolerance and width are easy to age; 10. Some plastics are soluble in solvents.