Steric Hindrance-Induced Microphase Structure Evolution and Synergistic Performance Optimization of High-Performance...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Polyurethane elastomers (PU) properties are dictated by soft and hard segment compatibility and microphase separation.
• Controlling microphase separation is key to optimizing PU mechanical and thermal performance.

Purpose of the Study:

• To develop a steric hindrance-based molecular design strategy for regulating microphase structure in nonpolar polybutadiene-based PU.
• To investigate the impact of this strategy on the interfacial compatibility, morphology, and overall properties of PU.

Main Methods:

• Utilized multiscale characterization techniques.
• Employed molecular simulations to analyze microphase separation.
• Introduced chain extenders with moderate steric hindrance.

Main Results:

• Disrupted ordered packing of hard segments, leading to an interfacial transition-type microphase separation (ITMS) structure.
• Achieved enhanced interfacial compatibility and morphological uniformity.
• Optimized PU (PU-2) demonstrated improved tensile strength (14.3 MPa), toughness (23.5 MJ·m⁻³), and energy dissipation (tan δmax > 1.0).

Conclusions:

• ITMS structure effectively enhances mechanical properties and energy dissipation in nonpolar PU.
• The steric hindrance molecular design strategy is a viable approach for optimizing PU performance.
• The optimized PU exhibits excellent dynamic loading stability, water resistance, electrical insulation, and biocompatibility.