Background: Cross-linking structure of polyurethanes determines no degradability of these materials.
However, introducing the hydrolysable substrates (of natural or synthetic origin) into the cross-linked
polyurethanes structure makes them biodegradable. Moreover compounds (such as polycaprolactone triol,
glycerin, lysine triisocyanate, etc.) that are used for polyurethane cross-linking are degraded in non-toxic products.
All these kinds of compounds can be introduced into soft or hard segments via urethane bonds.
Objective: The review focuses on kind of multifunctional polyols and isocyanates, and low molecular crosslinkers
used for cross-linked polyurethanes obtaining. These compounds are natural substrates (in the native
state or after modification) or are synthetic compounds with degradable linkages. They belong to polyesters,
plant oils, proteins, saccharides, and others (e.g. lignocellulosic materials), and they are synthesized chemically
or via biosynthesis by algae, plants, microorganisms, and by animals.
Conclusion: Incorporation of degradable groups (such as ester moieties) into the polymer structure, and using
of substrates with the structure known and metabolized by microorganisms for soft or hard segments building,
facilitate degradation of cross-linked polyurethanes.
State-of-the-Art Char Production with a Focus on Bark Feedstocks: Processes, Design, and Applications
