Synthesis of highly elastic biodegradable poly(urethane urea)

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomaterials

Background:

• Poly(urethane urea)s (PUUs) are versatile polymers with applications in various fields.
• Developing efficient and versatile synthesis methods for PUUs with tunable properties remains an active area of research.
• Biodegradable soft segments are desirable for environmentally friendly materials, but their integration can be challenging.

Purpose of the Study:

• To develop a novel, one-pot synthesis for linear poly(urethane urea)s (PUUs).
• To create PUUs with biodegradable soft segments and hard segments derived solely from methyl-2,6-diisocyanatehexanoate (LDI).
• To investigate the properties of the synthesized PUUs, including viscosity, elongation, and elastic modulus.

Main Methods:

• A one-pot synthesis was employed using methyl-2,6-diisocyanatehexanoate (LDI) in excess and a soft segment.
• Water was introduced in the vapor phase to generate amines in situ, forming urea linkages for hard segments.
• Polymers of trimethylene carbonate (TMC) and copolymers of TMC, epsilon-caprolactone, and D,L-lactic acid (DLLA) were used as soft segments.

Main Results:

• High inherent viscosity (0.95-1.65 dL/g) was achieved, even with DLLA-containing soft segments prone to aminolysis.
• Synthesized PUUs demonstrated very high elongation at breakage (1600%–4700%) with hard segment content between 12% and 18%.
• Elastic modulus ranged from 2.1 to 140 MPa, indicating tunable mechanical properties.

Conclusions:

• A simple and effective one-pot synthesis for linear PUUs with biodegradable soft segments was successfully demonstrated.
• The method allows for the formation of hard segments with multiple LDI units via in situ amine generation.
• The developed synthesis is applicable to a wide range of systems, offering a versatile route to high-performance biodegradable polymers.