【Haichuan Chemical: New Insights】New Strategies for the Value-Added Utilization of Thermosetting Plastic Waste
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Recently, the team led by Academician Wang Yuzhong from the School of Chemistry at Sichuan University adopted a concept of turning waste into resources, and through simple physical modification methods, successfully converted used thermosetting resins into an oil-water separation material with adjustable pore size. This method not only provides a new concept for the recycling of thermosetting plastics, but also offers a new approach for the design of oil-water separation materials.
Under microwave heating conditions, waste epoxy resin (EP) was swollen using the green solvent NMP to obtain swollen resin (SEP); subsequently, microwave-assisted pore formation was carried out to yield structurally stable porous resin (PEP), whose pore sizes were uniformly distributed around 80 nm. After modification, the surface roughness of the resin increased from 1.8 nm to 63.1 nm, and the water contact angle increased from 81° to 101°. The composition of the resin remained unchanged; therefore, it can be used in the field of oil-water separation while maintaining the good physicochemical properties of the thermosetting resin.
Without the need for external pressure, PEP relies on the gravity of the oil-water mixture to achieve efficient separation of oil-water emulsions; its separation flux for emulsions with a particle size of 3.5 μm reaches 2306.78 L (m2h)-1. Even after multiple cycles of use, PEP maintains a high separation efficiency and flux.
By changing the composition and ratio of the swelling solvent, the pore size of the resin can be regulated, thereby enabling efficient separation of emulsions with different particle sizes. The demulsification effect of PEP is optimal when the particle size of the emulsion is comparable to the pore size of the porous resin.