Toward Non-Isocyanate Polyurethanes: Green Synthesis Routes and Recycling Technologies

Area of Science:

• Polymer Chemistry
• Materials Science
• Green Chemistry

Background:

• Conventional polyurethanes (PUs) synthesis relies on toxic isocyanates, posing environmental and health hazards.
• Growing regulatory pressure necessitates safer alternatives to isocyanate-based PUs.
• Non-isocyanate polyurethanes (NIPUs) offer a promising eco-friendly alternative.

Purpose of the Study:

• To systematically review current advancements in green synthesis routes for NIPUs.
• To explore sustainable end-of-life management and recycling strategies for PUs.
• To highlight future prospects for environmentally friendly and recyclable NIPUs.

Main Methods:

• Review of literature on NIPU synthesis pathways, including Bis(dialkyl carbonate), Transurethanization, Cyclic carbonate, and Ring-opening polymerization (ROP) routes.
• Analysis of current PU disposal and recovery methods, focusing on chemical and mechanical recycling.
• Synthesis of recent progress in green chemistry for PU production and waste management.

Main Results:

• Identified four primary green synthesis routes for NIPUs, offering alternatives to hazardous isocyanates.
• Evaluated chemical degradation and mechanical recycling as key end-of-life management strategies for PUs.
• Highlighted chemical recycling's potential for achieving a closed-loop system for PUs.

Conclusions:

• NIPUs present a viable solution to the environmental and health concerns associated with conventional PUs.
• Advancements in green synthesis and chemical recycling are crucial for developing sustainable polyurethane materials.
• Further research into NIPU synthesis and recycling is essential to meet environmental regulations and promote a circular economy.