Cross-Linked Polythiomethacrylate Esters Based on Naphthalene-Synthesis, Properties and Reprocessing

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Novel aromatic dithioesters were synthesized.
• Polymer networks were prepared using methyl methacrylate (MMA) and/or styrene (ST) with these new dimethacrylates.

Purpose of the Study:

• To synthesize and characterize novel aromatic dithioesters.
• To investigate the thermal, mechanical, optical, and reprocessing properties of polymers containing these dithioesters.
• To explore the potential of thiol-ene chemistry for polymer recycling and property modification.

Main Methods:

• Synthesis of aromatic dithioesters.
• Polymerization of MMA and ST with dimethacrylates.
• Characterization using DSC, TG/DTG, Shore D hardness, UV/vis spectroscopy, and refractive index measurements.
• Swelling studies, depolymerization via thiol-thioester exchange, and reprocessing using thiol-ene reactions.

Main Results:

• High polymerization yields (95-99%) were achieved.
• Dithioester addition lowered glass transition temperature (Tg) by ~8 °C and improved refractive index.
• Thioester-containing polymers showed stability up to 250 °C, with MMA-based polymers having lower thermal stability than ST-based ones.
• Thiol-ene reprocessing yielded materials with altered thermal, mechanical (lower Shore hardness and Tg), and swelling properties.

Conclusions:

• Aromatic dithioesters can be effectively incorporated into polymer networks.
• Thiol-thioester exchange and subsequent thiol-ene reactions offer a viable route for polymer reprocessing and property tuning.
• This approach facilitates the creation of new materials with desired features, demonstrating potential for sustainable polymer manufacturing.