Recycling Thermoset Systems by Vitrimerization Using Solid-State Shear Extrusion- A Feasibility Study.

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Chemistry

Background:

• Thermoset polymers possess excellent mechanical properties but are difficult to recycle due to permanent cross-links.
• Vitrimerization offers a solution by creating adaptable networks, enabling reprocessing and recycling of thermosets.
• Current vitrimerization methods, like ball milling (BM), are often batch processes with limitations.

Purpose of the Study:

• To introduce solid-state shear extrusion (SSSE) as a continuous, room-temperature alternative to ball milling for epoxy vitrimerization.
• To evaluate the efficacy of SSSE in producing recyclable thermosets (vitrimers).
• To assess the mechanical properties and reprocessability of SSSE-derived vitrimers.

Main Methods:

• Utilizing solid-state shear extrusion (SSSE) for continuous vitrimerization of thermosets at room temperature.
• Comparing the activation energy and mechanical properties of SSSE-processed vitrimers with those obtained via ball milling (BM).
• Assessing the reprocessability and property retention of SSSE vitrimers over multiple cycles.

Main Results:

• SSSE successfully vitrimerized epoxy thermosets at room temperature, yielding materials with comparable activation energy to BM-processed vitrimers.
• The mechanical properties of SSSE vitrimers were similar to those produced by BM.
• SSSE-derived vitrimers demonstrated excellent reprocessability, retaining over 80% of their mechanical properties after multiple cycles.

Conclusions:

• Solid-state shear extrusion (SSSE) is a feasible and effective method for continuous, room-temperature vitrimerization.
• SSSE presents a scalable, energy-efficient, and environmentally friendly alternative to ball milling for industrial thermoset recycling.
• This approach facilitates closed-loop recycling of thermosets, addressing sustainability challenges in polymer waste management.