Question

Физические свойство полимеров

Answer 1

- Полиамид-6 Полиамид-6.6 Полиэтилен ПОМ (POM) ПВХ (PVC) (мягкий) ПВХ (PVC) (твердый) Полипропилен Полистирол (цельный) Полистирол (пенопласт) Фенол -формальдегидная смола

АБС (ABS) Полиуретан

Удельная масса , г/см 3 1.14 1.14 0.95 1.42 1.3 1.4 0.92 1.05 1.05 1.4 1.05 1.26

Предел прочности на разрыв , МН/м 2 55 60 24 75 16 60 32 55 55 25 50 50

Предел прочности на изгиб , МН/м 2 27 38 37 108 - - 44 35 - 70 - -

Относительноеудлинение при разрыве, % 250 140 350 65 400 40 350 30 30 - 3 600

Коэффициент эластичности, МН/м 2 950 1500 1000 3000 20 3000 1300 2500 2500 7000 2500 25

Ударная вязкость (прочность) , КДж/ м 2 35 17 3 8.5 - 30 6.5 6.5 6.5 1.7 12 -

Максимальная рабочая температура , o C 120 120 80 100 80 80 110 81 81 120 80 80

Удельное сопротивление, Ом*см 10^15 10^15 10^15 10^15 10^10 10^17 10^16 10^16 10^16 10^10 10^14 -

Тангенс угла диэлектрических потерь 0.2 0.15 0.001 0.025 0.1 0.1 0.0005 0.0004 0.0004 <0.3 0.015 0.1

Электрическая прочность , МВ*м 35 30 53 70 30 32 80 >40 >40 75 85 20

Горючесть, по UL94(США)>1.6мм V2 V2 - HB HB HB HB HB HB VO HB HB

Коэффициент трения по стали 0.3 0.3 0.25-0.3 0.25 - 0.5 0.5 0.5 0.5 0.5 0.5 0.15-0.4

Коэффициент линейного расширения ,

10 -6 /o C

Answer 2

Physical Properties of Polymers

Polymers are large molecules composed of repeating subunits called monomers. They exhibit a wide range of physical properties due to their unique molecular structure. Here are some key physical properties of polymers:

1. Molecular Weight: Polymers can have varying molecular weights, ranging from a few thousand to millions of atomic mass units (AMU).

2. Melting Point: The melting point of polymers can vary depending on their chemical composition and molecular structure. Some polymers have low melting points, while others have high melting points. For example, polyethylene has a melting point of around 110-130°C.

3. Glass Transition Temperature: The glass transition temperature (Tg) is the temperature at which an amorphous polymer transitions from a hard, glassy state to a rubbery state. It is influenced by factors such as molecular weight, chain flexibility, and intermolecular forces. Polymers with a high Tg are rigid and brittle at room temperature, while those with a low Tg are flexible and rubbery.

4. Solubility: Polymers can exhibit different solubility characteristics depending on their chemical structure. Some polymers are soluble in certain solvents, while others are insoluble. For example, polyethylene is insoluble in most organic solvents, while polyvinyl alcohol is soluble in water.

5. Density: The density of polymers can vary widely depending on their chemical composition. Some polymers have low densities, such as polyethylene, which has a density of around 0.92 g/cm³. Others, like polyvinyl chloride, have higher densities, around 1.4 g/cm³.

6. Mechanical Properties: Polymers can exhibit a wide range of mechanical properties, including tensile strength, elasticity, toughness, and hardness. These properties are influenced by factors such as the molecular weight, chain flexibility, and cross-linking of the polymer.

7. Thermal Stability: The thermal stability of polymers refers to their ability to withstand high temperatures without undergoing significant degradation. Some polymers have excellent thermal stability and can withstand temperatures above 400°C, while others may degrade at lower temperatures.

8. Electrical Properties: Polymers can exhibit both insulating and conducting properties depending on their chemical structure. Some polymers, like polyethylene, are good insulators, while others, like polyaniline, can conduct electricity.

It's important to note that the physical properties of polymers can vary greatly depending on their specific chemical composition, molecular structure, and processing conditions. Therefore, it is essential to consider these factors when working with polymers or selecting them for specific applications.

I hope this information helps! Let me know if you have any further questions.