Inverse Vulcanized Polymers with Shape Memory, Enhanced Mechanical Properties, and Vitrimer Behavior

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Inverse vulcanization enables functional polymer synthesis from elemental sulfur, a sustainable industrial byproduct.
• Limited mechanical properties of sulfur-polymers hinder their widespread application.
• Developing enhanced sulfur-based materials is crucial for sustainable polymer development.

Purpose of the Study:

• To develop an effective synthesis method for sulfur-polymers with significantly improved mechanical properties.
• To demonstrate control over material performance, including tensile strength, strain, hardness, and flexibility.
• To explore the potential for shape memory and recycling in these novel sulfur-polymers.

Main Methods:

• Synthesis of a linear, hydroxyl-functionalized pre-polymer from elemental sulfur.
• Crosslinking the pre-polymer using a difunctional isocyanate secondary crosslinker.
• Tuning material properties by adjusting the molar ratio of crosslinking functional groups.

Main Results:

• Achieved tunable tensile strength ranging from 0.14±0.01 MPa to 20.17±2.18 MPa and strain from 11.85±0.88% to 51.20±5.75%.
• Demonstrated control over hardness, flexibility, and solubility.
• Developed materials with excellent shape memory function and vitrimer-like recyclability due to dynamic S-S bonds.

Conclusions:

• The novel synthesis method significantly enhances the mechanical properties and performance control of sulfur-polymers.
• The resulting materials exhibit desirable properties like shape memory and recyclability, making them attractive for advanced applications.
• This approach broadens the potential applications of sustainable sulfur-polymers derived from industrial byproducts.