Microphase separation/crosslinking competition-based ternary microstructure evolution of poly(ether-b-amide)

Area of Science:

• Polymer Science
• Materials Science
• Rheology

Background:

• Poly(ether-b-amide) (PEBA) segmented copolymers exhibit complex behavior due to microphase separation.
• Understanding temperature-dependent structural evolution is crucial for material applications.

Purpose of the Study:

• To investigate the temperature dependence of PEBA rheological properties under oscillatory shear flow.
• To elucidate the roles of microphase separation and crosslinking in microstructural evolution.

Main Methods:

• Oscillatory shear rheology was employed to study PEBA samples at varying temperatures.
• Dynamic storage modulus was analyzed to determine microstructural changes.
• Key transition temperatures (T_cross) were identified.

Main Results:

• Microphase separation and irreversible crosslinking significantly influence the dynamic storage modulus.
• Heating above T_cross leads to dominant crosslinking, altering microstructure.
• Increased crosslinking enhances strain hardening during uniaxial stretching.

Conclusions:

• PEBA microstructure evolution upon heating can be categorized into three domains: homogenous, microphase separation dominating, and crosslinking dominating.
• Irreversible crosslinking above T_cross impacts rheological, crystallization, and mechanical properties.
• Crosslinking content is a key factor in PEBA's mechanical performance.