Provisions of the size of the sample in a certain temperature of the water, after 24 hours absorbed moisture, water absorption after the size and shape would be affected.

Permeability is:

A certain thickness of plastic film under an atmospheric pressure, each square meter area of ventilation quantity in 24 hours.

Moisture permeability:

Water vapor through the situation of plastic film.

Transparency:

Light transmittance, the luminous flux through the object and shot to the objects on the ratio of the luminous flux.

Haze or turbidity:

The upward astigmatism in incident light to all the ratio of the transmitted light

Haze is often a disc transparent but the nature of the incident light is diffuse.

2. the mechanical properties of plastic materials

Tensile strength:

In the specified test temperature, humidity, and stretching speed under the applied tensile force of the sample, the determination of its destruction yes maximum load.

The compression strength:

Places compression force on the samples, and the rupture (brittle) or yield.

Bending strength:

Samples on the two fulcrum, concentrated load, make the strength of the samples when the deformation or fracture.

The impact strength:

Samples of impact breakage when consumed by the joule per unit area.

The coefficient of friction:

The friction and the ratio of the positive pressure.

Abrasion:

Plastic in the process of friction size change of mechanical failure process (wear, abrasive wear)

Hardness:

The performance of the plastic pressure against other hard objects into. (rockwell, shore).

Fatigue:

Under a static damage and a small amount of alternating cycle make plastic damage.

Creep:

In a fixed temperature, humidity, plastic in fixed under the action of external force continued, change over time will show that the creep characteristics, its increases with load load, decrease with load reduction, and deformation gradually restored. (bending tensile creep, compression creep, creep, etc.)

Persistent strength:

Plastic for a long time through static load ability of high and low time function

3. the use of plastic material performance

Linear expansion coefficient:

Temperature rise 1 degree, each 1 mm plastic elongation of the mm number. As a general rule, be ten times the steel.

Specific heat:

1 gram of thermal units required for plastic raise the temperature of 1 degrees.

Coefficient of thermal conductivity:

A unit area and thickness of the plastic can through thermal units, 1% of the steel.

Heat resistance:

The relationship between the temperature and deformation.

Glass transition temperature:

Plastic by fell to a solid when the temperature of the molten fluid temperature, have very big brittleness.

Brittle temperature:

When the pressure must be under the low temperature of plastic, will damage under small deformation.

Melt index:

Thermoplastics under certain temperature and pressure, the outflow of melt in 10 minutes by testing hole plastic weight.

The combustion resistance:

By burning rate (length of time the sample combustion) and burning weightlessness rate (weight difference before and after combustion).

Withstand voltage:

E., quickly will increase the voltage to a certain time samples were not breakdown.

Aging resistance:

In the process of plastic in use, storage, processing due to light, heat, oxygen and biological, the effect of external factors such as stress, causes damage on the chemical structure and make the excellent properties of original decline phenomenon.

Chemical resistance:

Whether the plastic in the chemical medium from corrosion. (weight, volume, intensity, color, etc.)

Molding shrinkage rate:

Plastic molding, in mold cooling after demoulding shrinkage of FRP products.