Let us now discuss the properties of polyester:

Microscopic Properties:
• Longitudinal Section (L.S.): Polyester has a smooth, uniform and rod-like longitudinal cross-section.

• Cross Section (C.S.): Polyester fibers have a circular cross-section.

Physical Properties:

• Length and diameter: The length of the polyester fiber depends on the end use and can be controlled, while the diameter of the fiber varies from 12-25 meters.
• Colour and lustre: The color of the acrylic fiber is off-white with a bright luster because the incident light is evenly reflected when it falls on the smooth surface of the fiber.
• Tenacity: The toughness of polyester is quite high, between 2.5-9.5g/den. The presence of large crystalline regions in polyester fibers helps to enhance strength. Does not lose strength in wet conditions.
• Elongation and elastic recovery: Polyester fiber has good elastic recovery rate.
• Density: Polyester has a density of 1.39 g/oz, which makes it heavier than nylon.
• Resiliency: When the acrylic fiber is crushed or bent, it can be restored to the original position, so that the fiber has good resilience.
• Moisture regain: Polyester is hydrophobic because its crystal arrangement does not allow water to easily enter its structure.
• Thermal Property: Polyester fibers are thermoplastic in nature and can be easily thermally set, thus softening and forming.

Chemical Properties:
• Acids: Polyester fibers is acid-resistant.
• Alkalis: Polyester fiber has good alkaline resistance.

Polyester has excellent sun resistance, but it faces the problem of static electricity.