Polyurethane Elastomers Strengthened by Pseudo[1]rotaxanes Based on Pillararenes

Area of Science:

• Supramolecular Chemistry
• Polymer Science
• Materials Science

Background:

• Rotaxanes are interlocked molecular architectures enabling intramolecular motion.
• Incorporating rotaxanes into polymers can impart unique macroscopic properties and enhance mechanical performance.

Purpose of the Study:

• To synthesize novel polyurethane elastomers with built-in pseudo[1]rotaxane structures.
• To investigate the impact of molecular motion and coordination chemistry on elastomer properties.

Main Methods:

• Preparation of a copillar[5]arene pseudo[1]rotaxane via intramolecular hydrogen bonds.
• Incorporation of the pseudo[1]rotaxane into a polyurethane backbone.
• Mechanical testing including stress-strain analysis and dynamic mechanical analysis.
• Modification with cuprous bromide to introduce coordination bonds.

Main Results:

• The synthesized polyurethane elastomers exhibit spring-like structures due to the pseudo[1]rotaxane.
• Molecular sliding within the rotaxane effectively dissipates energy, leading to increased toughness and fatigue resistance.
• Addition of cuprous bromide further enhances mechanical properties through cuprous-thioether coordination.

Conclusions:

• Pseudo[1]rotaxane-based polyurethane elastomers demonstrate superior energy dissipation capabilities.
• The designed molecular architecture offers a promising route to high-performance elastomers.
• Coordination chemistry provides an additional strategy for fine-tuning material properties.