Confined Drawn PET Sheet

Annealing enhances orientation

Highly oriented poly(ethylene terephthalate) sheet produced by confined drawing and annealing under tension, with improved ordered structure and enhanced mechanical properties.

Yukun, Zheng · Liu, Xuanbo · Su, Cui · Ren, Minqiao · Yachao, Zhao · Gao, Dali

Polymer 2026

Advantages

Annealing significantly enhances orientation

The orientation of ordered structures is significantly enhanced, leading to more regular molecular arrangement and improved mechanical properties.

Promotes primary crystallite perfection

The perfection of primary crystallites is improved, reducing crystalline defects and enhancing strength and thermal stability.

Induces secondary crystallite formation

Highly ordered rigid amorphous fraction (RAF) transforms into secondary crystallites, increasing crystalline content and further strengthening the material.

Optimal annealing temperature favors transitional phase

Appropriate annealing temperatures favor the presence of transitional phases, which positively contribute to mechanical properties.

Applications

• High-strength polymer films：Replaces standard PET films with annealed oriented sheets for high-strength packaging or substrates.
• Flexible device substrates：Provides highly oriented, high-strength flexible substrates to support mechanical stability in flexible electronics.
• High-performance structural materials：Achieves higher crystallinity and orientation via controlled annealing to meet structural requirements for strength and dimensional stability.
• Fiber-reinforced composites：Highly oriented PET can serve as reinforcement or prepreg substrate to enhance mechanical properties of composites.