Polyester yarn is not cotton. While both polyester and cotton are commonly used materials in the textile industry, they have distinct characteristics and are derived from different sources.

Polyester is a synthetic fiber made from a polymer called polyethylene terephthalate (PET). It is derived from petroleum, a non-renewable resource. Polyester yarn is produced through a process called polymerization, where the PET molecules are chemically linked to form long chains. These chains are then spun into fibers, which are further processed to create polyester yarn.

Cotton, on the other hand, is a natural fiber derived from the seeds of the cotton plant (Gossypium). It has been used for thousands of years and is known for its softness, breathability, and moisture-absorbing properties. Cotton fibers are composed of cellulose, a complex carbohydrate found in the cell walls of plants.

Here are some key differences between polyester yarn and cotton:

1. Source: Polyester yarn is made from petroleum, a non-renewable resource, while cotton is derived from the renewable cotton plant.
2. Production Process: Polyester yarn is produced through a chemical process, involving the polymerization of PET molecules. Cotton fibers, on the other hand, are harvested from cotton plants, cleaned, and processed into yarn.
3. Feel and Comfort: Polyester yarn tends to have a smooth and synthetic feel, whereas cotton yarn is known for its softness and natural feel. Cotton is often preferred for its comfort and breathability, making it suitable for a wide range of applications, including clothing, bedding, and towels.
4. Moisture Absorption: Cotton has high moisture-absorbing properties, allowing it to absorb and release moisture easily. Polyester, however, is hydrophobic and does not absorb moisture as effectively. This property can lead to a less breathable and potentially uncomfortable experience when wearing polyester garments in hot and humid conditions.
5. Wrinkle Resistance: Polyester yarn is known for its wrinkle resistance and ability to retain its shape, even after repeated washing. Cotton, on the other hand, is more prone to wrinkling and may require ironing or steaming to remove wrinkles.
6. Durability: Polyester yarn is generally more durable than cotton yarn. It is resistant to stretching, shrinking, and most chemicals, making it suitable for applications that require strength and longevity. Cotton, while still durable, may wear out more quickly over time, especially with frequent washing and use.
7. Environmental Impact: Polyester production has a greater environmental impact compared to cotton. The production of polyester involves the extraction and processing of petroleum, which is an energy-intensive process and contributes to carbon emissions. Cotton, while a natural fiber, requires significant amounts of water for cultivation and can be associated with issues such as water pollution and pesticide use. However, efforts are being made to develop more sustainable and eco-friendly production processes for both polyester and cotton.

In summary, polyester yarn and cotton are two distinct materials with different properties and production processes. Polyester is a synthetic fiber made from petroleum, while cotton is a natural fiber derived from the cotton plant. While polyester offers durability and wrinkle resistance, cotton is known for its softness, breathability, and moisture-absorbing properties. The choice between the two depends on the specific requirements of the application and individual preferences for comfort, sustainability, and environmental impact.