Non-Isocyanate Aliphatic-Aromatic Poly(carbonate-urethane)s-An Insight into Transurethanization Reactions and...

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Non-isocyanate poly(carbonate-urethane)s (NIPCUs) offer a safer alternative to traditional polyurethanes.
• Understanding transurethanization reactions is key to controlling NIPCU synthesis and properties.

Purpose of the Study:

• To investigate the influence of alkyl chain length in 4,4'-diphenylmethylene bis(hydroxyalkyl carbamate) (BHAC) on transurethanization reactions.
• To establish structure-property relationships in aliphatic-aromatic NIPCUs.

Main Methods:

• Synthesis of BHAC with varying alkyl chain lengths.
• Characterization of NIPCUs using ¹H and ¹³C NMR and FT-IR spectroscopy.
• Evaluation of mechanical properties, including tensile strength and elongation at break.

Main Results:

• Shorter alkyl chains (ethyl, butyl) in BHAC led to susceptibility to back-biting side reactions.
• Longer alkyl chains (pentyl, hexyl, decyl) in BHAC prevented side reactions.
• Increased alkyl chain length in NIPCU hard segments enhanced elongation at break and crystallinity while reducing tensile strength and hardness.
• Achieved exceptional NIPCU mechanical properties (40 MPa tensile strength, 130% elongation at break).

Conclusions:

• Alkyl chain length is a critical factor in controlling NIPCU synthesis via transurethanization.
• Optimized NIPCU structures exhibit superior mechanical properties suitable for demanding applications.
• The study provides a pathway for designing high-performance, safer polyurethanes.