Fabrication and Characterization of PEEK/PEI Multilayer Composites

Area of Science:

• Materials Science
• Polymer Science
• Composite Materials

Background:

• Polyetheretherketone (PEEK) and polyetherimide (PEI) are high-performance polymers with distinct properties.
• Achieving controlled miscibility in polymer blends is crucial for tailoring material characteristics.

Purpose of the Study:

• To investigate the interfacial properties and structural evolution of PEEK/PEI multilayer blends.
• To evaluate the impact of processing time on the miscibility and mechanical performance of these blends.

Main Methods:

• Alternate layer stacking of PEEK and PEI (50/50, v/v).
• Characterization using Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), and X-ray synchrotron.
• Mechanical testing of multilayer films compared to pristine polymers.

Main Results:

• Preservation of distinct PEEK and PEI layers with a mixed interfacial zone.
• Monitoring of glass transition temperatures (T_g) showing isolated values for both polymers.
• Slight decrease in PEEK crystallinity, with preserved crystal parameters.
• Enhanced mechanical properties (Young's modulus, tensile strength, strain at break) in multilayer samples processed for shorter durations.

Conclusions:

• The alternate layer stacking strategy effectively controls miscibility, maintaining pristine polymer phases.
• The interfacial zone grows with processing time, but distinct layers persist.
• Shorter processing times optimize the mechanical performance of PEEK/PEI multilayer blends, preserving PEEK crystallinity.