Oligo(epsilon-caprolactone)-based polymer networks prepared by photocrosslinking in solution

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomaterials Engineering

Background:

• Adjustable polymer networks are crucial for developing advanced biomaterials.
• UV-crosslinking of endgroup-functionalized oligoesters offers versatile material properties.
• Crosslinking conditions significantly influence the final network characteristics.

Purpose of the Study:

• To investigate the impact of crosslinking conditions (melt vs. solution) on polymer network properties.
• To compare the thermal, mechanical, and swelling characteristics of networks synthesized via different methods.
• To explore the potential of solution crosslinking for creating novel biomaterial properties.

Main Methods:

• Synthesis of oligo(epsilon-caprolactone)-(z)methacrylate (oCL-(z)IEMA) precursors with linear (di) and star-shaped (tetra) architectures.
• UV-initiated radical polymerization for crosslinking precursors in both melt and solution states.
• Characterization of thermal, mechanical (Young's modulus, maximum stress, elongation at break), and swelling properties of the resulting polymer networks.

Main Results:

• Solution crosslinking yielded materials with lower Young's moduli and maximum stress but higher elongation at break at 70 °C compared to melt crosslinking.
• Star-shaped precursors (8 kDa) produced poorly elastic networks in melt but highly stretchable, semi-crystalline materials with high gel content and elongation at break when crosslinked in solution.
• Crosslinking conditions significantly altered the morphology and mechanical performance of the polymer networks.

Conclusions:

• The method of crosslinking (melt vs. solution) critically influences the properties of methacrylate-functionalized polymer networks.
• Solution-based synthesis enables the creation of semi-crystalline elastic materials from star-shaped telechelic precursors, properties not achievable through melt processing.
• Tailoring crosslinking conditions provides a powerful strategy for designing advanced polymer network biomaterials with specific functionalities.