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Volume Change during Creep and Micromechanical Deformation Processes in PLA-PBSA Binary Blends
Laura Aliotta1,2, Vito Gigante1,2, Maria-Beatrice Coltelli1,2
1Department of Civil and Industrial Engineering, University of Pisa, 56122 Pisa, Italy.
Polymers
|July 24, 2021
Summary
This study reveals that adding poly(butylene succinate-adipate) (PBSA) to poly(lactic acid) (PLA) enhances stress intensity but lowers adhesion, causing earlier debonding in biopolymer blends under creep conditions.
Area of Science:
- Materials Science
- Polymer Science
- Biomaterials Engineering
Background:
- Poly(lactic acid) (PLA) and its blends are promising bio-based plastics.
- Understanding their micromechanical behavior under stress is crucial for application development.
Purpose of the Study:
- To investigate the micromechanical behavior of poly(lactic acid) (PLA) and poly(butylene succinate-adipate) (PBSA) blends.
- To correlate creep, dilatation variation, and micromechanical deformation processes.
Main Methods:
- Creep measurements using an optical extensometer and universal testing machine.
- Scanning Electron Microscopy (SEM) for visualizing deformation.
- Application of analytical models, including Eyring plots, to biopolymer blends.
Main Results:
- A significant change in Eyring plots indicated the onset of cavitation/debonding.
- PBSA addition increased the apparent stress intensity factor due to lower interfacial adhesion.
- Debonding was identified as the primary mechanism for volume variation, initiating earlier in the 85-15 blend.
Conclusions:
- The introduction of PBSA influences the micromechanical response of PLA.
- Interfacial adhesion plays a critical role in the creep behavior of these biopolymer blends.
- Debonding is a key failure mechanism in PLA-PBSA blends under creep stress.
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