1–the microscopic shape of the fibers: polyester fibers have a soft surface without wrinkle.

2–special weight of the fibers: special weight of the fibers is about 1/38

3-lenghth and caliber of the fibers: length and caliber of the fibers can be determined according to the kind of usage.

4-durability of the polyester fibers: polyester fibers have a good durability. Durability of the short fibers is about 3/4 to 4 deniers.

5-property of being anti-wrinkle: polyester fibers have a great resistance against wrinkling and this is due to having a good elasticity.

6-the effect of heat on the fibers: polyester fibers show a considerable resistance against heat and melt in 250 centigrade degree.

7-absorbing of the moistness of the fibers: moistness absorbing of the fibers is minimal and at most 0/4% in standard situations.

8-elasticity of the fibers: elasticity of the polyester fibers is good and as a result, clothes which are produced from polyester won’t wrinkle and maintain its shape.

Polyester is crystal shape due to its chemical structure. Because of the absence of the active elements in its polymer and minimal absorbing of the moistness it has a good resistance against most of the chemicals.

_the effect of the alkaline:

Diluted alkaline won’t effect on polyester fibers and hot and strong alkaline won’t harm them.

_the effect of the oxidants:

Polyester fibers have a good resistance against the oxidants and generally most of the alcohols, soaps, detergents and substances used in dry cleaning won’t harm them.

_the effect of the acids:

Polyester fibers are in the state of boiling against weak acids and resistant against cold and strong acids.

_resistance against biological agents:

Biological agents such as moth mold and bacteria won’t harm the fibers.