1. Melt index
Under a certain temperature and pressure, the number of grams of molten resin extruded from a certain hole in 10 minutes is called the melt index, expressed in MI, and the unit is g/min.
2. Cold resistance
The ability of plastics to buy AAAC conductor maintain certain physical and mechanical properties at low temperatures is called the cold resistance of plastics. It is often expressed by the following cold-resistant temperature.
1) Low temperature embrittlement temperature: it is the temperature at which 50% of the ACSR conductor full form samples are damaged when the plastic is subjected to a specific impact load at a low temperature.
2) Low temperature half-folding temperature: it is the temperature at which the plastic sample is about to rupture when it is bent 180o.
3) Low-temperature impact compression temperature: it is the temperature at which the plastic sample is impacted and compressed by a hammer with a certain energy and speed at a low temperature to make the rupture rate reach 50%.
11. Flame resistance
Flame resistance refers to the ability of plastics to resist flame burning. Generally, plastics will burn after contacting the flame. After the flame is removed, the flame extension varies with different types of plastics, so the flame resistance performance is also different.
3. Heat aging performance
In the process of plastic processing and use, the performance of the plastic deteriorates due to heat. This phenomenon is called thermal aging. The ability of plastics to resist heat aging is called heat aging resistance. Use accelerated thermal aging test at high temperature to determine the retention rate of plastic properties (mechanical properties or electrical properties) after aging to measure the heat aging resistance of plastics.
4. Weather resistance
Plastics are used under atmospheric conditions and are affected by harsh natural conditions such as sunlight, rain, wind, and air pollution. The deterioration of plastic performance is called atmospheric aging. The ability of plastics to resist atmospheric aging is called the weather resistance of plastics.
5. Oil resistance and solvent resistance
When plastic comes into contact with mineral oil or various solvents, its ability to resist oil or solvent is called the oil resistance or solvent resistance of the plastic. The sample can be immersed in oil or solvent, and after a certain time at a certain temperature, the absorption rate, volume change rate or tensile strength and elongation retention rate of the oil or solvent can be measured.
6. Water resistance and humidity resistance
The ability of plastics to resist the penetration of water or humid gas under water or humid conditions is called the water resistance or moisture resistance of plastics. After the plastic absorbs water or moisture, it will cause a decrease in insulation resistance, breakdown field strength, increase in dielectric loss, and changes in the appearance, weight, and mechanical properties of the plastic. Therefore, plastics are required to have good water resistance and moisture resistance. For plastics used in wires and cables, the main consideration is to ensure that the electrical insulation properties of the plastics meet the requirements of use after immersion or moisture absorption. The water absorption of plastic can be expressed by the water absorption per unit area, the water absorption rate or the water absorption weight. The moisture permeability of plastics is expressed in terms of moisture permeability coefficient and vapor permeability.