Unique Method for Facile Postsynthetic Modification of Nonisocyanate Polyurethanes.

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Nonisocyanate polyurethanes (NIPUs) offer a safer alternative to conventional polyurethanes (PUs) by avoiding toxic isocyanates.
• Poly(hydroxyurethane)s (PHUs), a common NIPU type, suffer from high hydrophilicity and moisture-induced degradation.
• This limits their application due to poor thermomechanical performance and physical stability in humid conditions.

Purpose of the Study:

• To develop a simple and scalable method for modifying PHUs to enhance hydrophobicity.
• To improve the moisture resistance and overall properties of PHUs.
• To explore the potential for imparting diverse functionalities to PHUs.

Main Methods:

• Modification of PHUs via reaction between polymer backbone hydroxyl groups and aldehydes.
• Utilizing various aldehydes, including aromatic ones, for the modification reaction.
• Quantifying the degree of modification and water uptake under controlled humidity.

Main Results:

• Achieved high modification degrees (up to 84%) of the PHU backbone.
• Reduced water uptake by up to threefold at 85% relative humidity.
• Demonstrated retention of mechanical properties across a wide humidity range, especially with aromatic aldehydes.

Conclusions:

• Aldehyde modification effectively enhances the hydrophobicity and stability of PHUs.
• The developed method provides a versatile platform for tuning PHU properties beyond moisture resistance.
• Modified PHUs exhibit performance comparable to conventional PUs, expanding their potential applications.