A constitutive law for degrading bioresorbable polymers

Area of Science:

• Materials Science
• Polymer Science
• Biomaterials Engineering

Background:

• Biodegradable polymers are crucial in medical applications.
• Understanding their mechanical property changes during biodegradation is essential for device design.
• Existing models often lack comprehensive predictions for key mechanical parameters.

Purpose of the Study:

• To develop a constitutive law predicting elastic moduli, Poisson's ratio, and ultimate tensile strength of bioresorbable polymers undergoing biodegradation.
• To model the effects of chain scission and recrystallization on polymer mechanical behavior.

Main Methods:

• Hydrolysis reaction mechanism considered for chain scission.
• Semi-crystalline polymers modeled as solids with cavities (scissions) and inclusions (recrystallized regions).
• Utilized existing theories for effective elastic properties of composite solids and scaling relations for porous materials.

Main Results:

• Developed a constitutive law integrating elastic properties and tensile strength predictions.
• The model successfully captures trends in experimental data for various biodegradable polymers.
• Demonstrated the ability to predict changes in elastic moduli and tensile strength.

Conclusions:

• The proposed constitutive law provides a comprehensive framework for predicting the mechanical behavior of degrading bioresorbable polymers.
• This model can aid in the design and optimization of biodegradable medical devices.
• The findings offer valuable insights into the relationship between biodegradation processes and material performance.