Bio-Based Thiol-ene Network Thermosets from Isosorbide and Terpenes.

Area of Science:

• Polymer Chemistry
• Sustainable Materials Science
• Organic Synthesis

Background:

• Thermoset polymers offer excellent mechanical properties but pose end-of-life challenges due to permanent cross-linking.
• Developing inherently degradable thermosets from renewable resources is crucial for sustainable polymer chemistry.
• Renewably derived monomers for thermoset networks remain an underexplored area.

Purpose of the Study:

• To synthesize novel, degradable thermoset networks using sugar- and terpene-based monomers.
• To investigate the mechanical and thermal properties of these renewably derived networks.
• To assess the degradability of the synthesized thermoset materials.

Main Methods:

• Synthesis of novel sugar- and terpene-based monomers for thiol-ene network formation.
• Cross-linking monomers via thiol-ene click chemistry.
• Characterization of mechanical properties (e.g., strain-at-break, stress-strain behavior) and thermal properties (e.g., degradation temperature, glass transition temperature).
• Evaluation of network degradation under basic conditions.

Main Results:

• Synthesized thermoset networks exhibited a wide range of mechanical properties, with strain-at-breaks from 12% to 200%.
• Networks displayed varied mechanical responses, including plastic deformation and linear stress-strain behavior, depending on the thiol used.
• Thermal degradation occurred below 200 °C, with glass transition temperatures ranging from -17 °C to 31 °C.
• Nearly all synthesized thermosets showed complete degradation within 2 days under basic conditions.

Conclusions:

• Renewably derived monomers from sugars and terpenes can be used to create a diverse library of degradable thermoset networks.
• The choice of thiol cross-linker significantly influences the mechanical and thermal properties of the resulting networks.
• These findings expand the scope of sustainable polymer chemistry by providing tunable, degradable thermoset materials from renewable feedstocks.