Strengthen oriented poly (L-lactic acid) monofilaments via mechanical training

Area of Science:

• Biomaterials Science
• Polymer Engineering
• Medical Device Development

Background:

• Polymer materials, especially Poly (L-lactic acid) (PLLA), are crucial for biodegradable medical devices like stents due to biocompatibility.
• PLLA is a viscoelastic material prone to creep under sustained stress, impacting its mechanical performance.
• Enhancing PLLA mechanical properties is vital for advanced biomedical applications.

Purpose of the Study:

• To investigate the use of creep phenomenon to improve the mechanical properties of Poly (L-lactic acid) (PLLA) monofilaments.
• To explore controlled mechanical training methods for PLLA enhancement.
• To assess the impact of creep-induced structural changes on PLLA mechanical attributes.

Main Methods:

• Subjecting highly oriented PLLA monofilaments to controlled, constant force stretching (creep).
• Evaluating mechanical characteristics using tensile testing and dynamic mechanical analysis.
• Analyzing microstructural changes with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM).

Main Results:

• Achieved a 67% increase in total elongation and over a 20% rise in storage modulus after mechanical training.
• Microscopic analyses revealed enhanced molecular chain spacing and cavity formation.
• Mechanical improvements are linked to molecular chain unraveling and ordering in amorphous regions.

Conclusions:

• Controlled creep-induced mechanical training is a promising strategy to augment PLLA monofilament properties.
• Enhanced PLLA mechanical performance can benefit the development of biodegradable medical devices.
• This approach offers a pathway for optimizing polymer-based biomedical engineering solutions.