Polyester fibers are a class of polymer fibers. According to the different molecular composition, they have unique properties, such as high strength, light weight, easy washing and quick drying, good elasticity, anti-mildew and so on. As a supplier of fiber solutions, Alfa Chemistry offers a wide range of polyester fiber products to meet your fiber material needs.
Categories
- PET Fiber
Polyethylene terephthalate (PET) is the main polyester used in fiber production. PET is a semi-crystalline polymer, and the physical parameters of PET have been summarized in the table below. PET fiber is the most produced synthetic fiber in the world. PET fiber has high strength, good elasticity, excellent heat setting performance, good heat resistance, acid and alkali resistance and other properties.
| Crystal habit | Triclinic: one polymer chain per unit cell |
| Cell parameters | a = 0.444 nm; b = 0.591 nm; c = 1.067 nm, α = 100 degrees; β= 117 degrees; γ = 112 degrees |
| Cell density | 1.52 g/cm3 |
| Tm (DSC) | 260°C ~ 265°C |
| ΔHf | 140 J/g; 33.5 cal/g |
| Tg (solid chip) | 79°C (DSC) |
| Tg (drawn fiber) | 120°C (dynamic loss) |
| Specific gravity | 1.33 (amorphous, undrawn), 1.39 (crystalline drawn fiber) |
- Other Polyester Fibers
Other polyester fibers include polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), poly-1,4-cyclohexanedimethyl terephthalate, Polyethylene 2,6-naphthalate fibers, and various modified polyester-based fibers. Among them, PBT fiber has excellent resilience, mildew and moth resistance, good curling elasticity, antistatic property and dyeing property. PTT fiber has excellent dimensional stability, stain resistance, wrinkle resistance, abrasion resistance and easy dyeing.
Structure
- Chemical Structure
Polyester fibers are synthetic fibers composed of polyester linear macromolecules produced by polycondensation of diols and dibasic acids or ω-hydroxy acids. The chemical structure of polyester fibers involves two aspects, one is the molecular level (molecular chain and its structure), and the other is the supramolecular level (crystalline and amorphous regions).
PET fibers have rigid benzene rings in their backbone. A single chain contains the sequence of six aliphatic groups (-CO-O-CH2-CH2-O-CO-). The practical coplanar arrangement of benzene rings, carboxyl groups and aliphatic molecular groups in adjacent chains allows for side-by-side alignment. The molecular chain structure of PET is shown in the figure. Therefore, the PET macromolecular chain shows great rigidity, which makes the PET fiber show some inherent characteristics, such as higher melting point, higher rigidity and higher strength of the fiber.
Chemical structure of PET
Polyester fibers can be thought of as being composed of crystalline, oriented amorphous (mesophase, binding molecules) and non-crystalline (amorphous) domains. Three-phase structural models of polyester and polyamide fibers are proposed as figure below. The model includes microfibrils containing alternating amorphous and crystalline regions; these are interconnected by amorphous fibril phases formed primarily of linking molecules. Each phase is characterized by its volume fraction and orientation. [2]
Structural model of semicrystalline fibers [2]
- Fiber Structure
The fiber structure is highly dependent on the process parameters of fiber formation, such as spinning speed, drawing, and heat-setting. The final fiber structure is highly dependent on temperature, draw rate, draw ratio, relaxation and heat-setting conditions. The crystalline and amorphous orientation and the percentage of crystallinity can be adjusted significantly in response to these process parameters.
References
- Michel Jaffe, et al. Thermal Analysis of Textiles and Fibers, 2020, 133-149.
- J. Militky. Handbook of Tensile Properties of Textile and Technical Fibres, 2009, 223-314.
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