Alkaline degradation study of linear and network poly(ε-caprolactone)

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Polycaprolactone (PCL) is a biodegradable polyester with tunable properties.
• Investigating PCL degradation is crucial for applications in drug delivery and tissue engineering.
• Understanding degradation mechanisms informs material design and predicts in vivo performance.

Purpose of the Study:

• To investigate the alkaline hydrolysis of a polycaprolactone (PCL) network.
• To compare the degradation kinetics and mechanisms of PCL networks versus linear PCL.
• To assess the impact of degradation on the physical and mechanical properties of PCL.

Main Methods:

• Photopolymerization of PCL macromers to form a PCL network.
• Alkaline hydrolysis experiments to study degradation kinetics.
• Calorimetry (DSC) to analyze changes in crystallinity.
• Scanning electron microscopy (SEM) for morphological analysis.
• Mechanical testing to evaluate property changes.

Main Results:

• PCL network degradation is substantially faster (60 h) than linear PCL (600 h).
• Degradation occurs in both crystalline and amorphous phases simultaneously, with no change in crystallinity.
• SEM reveals bulk erosion in PCL networks and surface erosion in linear PCL.
• Mechanical properties decline due to increased porosity from degradation.

Conclusions:

• PCL networks exhibit accelerated degradation compared to linear PCL under alkaline hydrolysis.
• Distinct erosion mechanisms (bulk vs. surface) are identified for network and linear PCL.
• Degradation-induced porosity significantly affects the mechanical integrity of PCL materials.