Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique...

Area of Science:

• Polymer Science
• Materials Science
• Solid-State NMR Spectroscopy

Background:

• Copolymers of glycolide, lactide, and caprolactone are important biomaterials.
• Understanding their molecular dynamics is key to tailoring material properties.

Purpose of the Study:

• To investigate the molecular dynamics of Gly/Lac/Cap copolymers.
• To determine the influence of copolymer composition on relaxation behavior and molecular mobility.

Main Methods:

• Differential Scanning Calorimetry (DSC)
• Fourier Transform Infrared Spectroscopy (FTIR)
• Proton (¹H) and Carbon-13 (¹³C) solid-state Nuclear Magnetic Resonance (NMR) spectroscopy
• Analysis of relaxation times (T₁), activation energies, and correlation times over a temperature range of 100-413 K.

Main Results:

• Methyl group reorientation in lactide dominates low-temperature relaxation.
• Transitions around 270 K and 294 K indicate changes in amorphous phase mobility.
• Caprolactone content enhances molecular mobility and flexibility, lowering the glass transition temperature.
• Lactide content restricts motion, increasing the glass transition temperature and slowing global dynamics.
• Activation energy for segmental motion increases with caprolactone content.

Conclusions:

• Copolymer composition is a critical factor in controlling molecular dynamics and relaxation.
• The balance between glycolide, lactide, and caprolactone allows for tuning of material flexibility and thermal properties.
• These findings provide insights for designing advanced biodegradable polymers.