Multi-Functional Hybrid Terpolymer Thermosets Based on Thiols Bio-Based Epoxy and Benzoxazine Monomers

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Thermosetting polymers offer excellent mechanical and thermal properties.
• Epoxidized linseed oil (ELO) and eugenol-based benzoxazine (EPB) are bio-based monomers with potential for polymer synthesis.
• Thiol-ene chemistry provides efficient crosslinking pathways.

Purpose of the Study:

• To synthesize and characterize novel hybrid thermosetting terpolymers.
• To investigate the effect of thiol concentration on curing dynamics and material properties.
• To evaluate the potential of these terpolymers as flame-resistant coatings.

Main Methods:

• Synthesis of terpolymers from ELO, EPB, and varying concentrations of 2SH and 3SH thiols.
• Monitoring curing kinetics using differential scanning calorimetry (DSC) and Fourier transform infrared spectrometry (FTIR).
• Assessing mechanical properties via dynamic mechanical analysis (DMA) and nanoindentation.

Main Results:

• FTIR and DSC revealed multi-step curing processes dependent on thiol concentration.
• Mechanical properties were tunable, achieving high stiffness at 0.25 wt.% thiol and increased flexibility at 1% thiol.
• Hybrid terpolymers exhibited higher crosslinking density, good monomer compatibility, and additional chemical bond formation.
• Materials demonstrated good thermal stability up to 300 °C with high residual mass (>25%).

Conclusions:

• The developed hybrid terpolymers offer tunable mechanical performance through controlled thiol crosslinking.
• The materials exhibit excellent thermal stability and flame-resistant characteristics.
• These terpolymers are promising candidates for advanced flame-resistant coating applications.