Why does PET strapping have good tensile and elastic properties?

1. Characteristics of molecular structure

High crystallinity: PET is a polymer with high crystallinity, and materials with high crystallinity typically have stronger mechanical properties, including tensile strength and elasticity. The crystalline structure tightly arranges PET molecules, which helps to enhance the strength and durability of the material.

The long-chain structure of molecular chains: PET molecules contain long and strong molecular chains, and the interaction forces between molecular chains (such as van der Waals forces, hydrogen bonds, etc.) make the material have high tensile resistance. Due to the relatively strong traction of molecular chains, PET can exhibit good ductility and tensile properties under stress.

2. Stretching process during manufacturing

Orientation: During the production process, PET strapping is usually subjected to thermal stretching treatment. By stretching PET film under heating, the molecular chains in the material can be arranged more neatly along the stretching direction. After thermal stretching, the structure of PET molecules becomes more ordered, which not only improves the tensile strength but also enhances the elasticity of the material.

Directional stretching: During the hot stretching process, PET molecular chains will be arranged more parallel in the longitudinal direction, and this oriented molecular structure makes PET strapping have significant tensile strength. At the same time, this directional structure also provides elasticity, allowing it to return to its original state after stretching.

3. Good elasticity

Elastic recovery ability of molecular chains: Due to the flexibility and arrangement characteristics of PET molecular chains, the material can effectively absorb stress when subjected to external tension and restore its original state after the external force is removed. PET has strong elastic recovery ability, so even during long-term use, it can still maintain good deformation recovery ability.

High elasticity of polymers: Polyester materials such as PET usually have high elasticity and can withstand significant external forces to deform and restore their original state. During the packaging process, PET strapping can “tighten” the goods to a certain extent and maintain a tight state. This elasticity helps it reduce the looseness caused by vibration or external impact during transportation.

4. Intermolecular interactions

Strong intermolecular forces: The hydrogen bonds and van der Waals forces between PET molecules make the packaging tape highly resistant to stretching. These intermolecular attractive forces enable PET materials to not only resist external stretching, but also restore their original state, thus exhibiting strong elasticity.

5. Adapt to various environmental conditions

PET strapping can maintain good tensile and elastic properties under different temperature and humidity conditions, which enables it to work effectively in various environments. Even in low-temperature environments, PET does not become brittle like some plastics, but still maintains good ductility and elasticity.