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A Novel Plasticization Mechanism in Poly(Lactic Acid)/PolyEthyleneGlycol Blends: From Tg Depression to a Structured
Nawel Mechernene1, Lina Benkraled1, Assia Zennaki1
1Laboratoire de Recherche sur les Macromolécules (LRM), Faculté des Sciences, Université Abou Bekr Belkaid de Tlemcen, BP 119, Tlemcen 13000, Algeria.
Polymers
|February 13, 2026
Summary
Polyethylene glycol (PEG) effectively plasticizes polylactic acid (PLA), but its impact on properties like viscosity depends heavily on processing-induced crystallinity and thermal history. Controlling these factors is key for flexible packaging applications.
Area of Science:
- Polymer Science
- Materials Science
Background:
- Polylactic acid (PLA) is a biodegradable polymer with limited applications due to brittleness.
- Polyethylene glycol (PEG) is a potential plasticizer, but its effects on PLA at intermediate molecular weights (e.g., 4000 g/mol) are not fully understood.
Purpose of the Study:
- To comprehensively analyze the thermal, mechanical, and rheological properties of PLA plasticized with PEG 4000.
- To investigate the influence of processing-induced crystallinity on PEG's plasticizing efficiency in PLA.
Main Methods:
- Differential Scanning Calorimetry (DSC) for thermal properties and miscibility.
- Dynamic Mechanical Analysis (DMA) for mechanical response and thermal history effects.
- Rheology to study melt viscosity and elasticity.
Main Results:
- Excellent miscibility and significant glass transition temperature (Tg) depression observed with PEG 4000.
- Non-monotonic crystallinity evolution and dependence of plasticizing effect on thermal history (crystalline vs. amorphous states).
- Anomalous melt viscosity increase at intermediate PEG concentrations, attributed to residual crystalline domains, not molecular networks.
Conclusions:
- PEG 4000 is an effective PLA plasticizer, with its performance critically dependent on processing-induced crystallinity.
- Controlling thermal history is essential for optimizing PLA's flexibility and processability.
- Findings provide guidelines for using PLA in flexible packaging and other melt-processed applications.
Keywords:
biodegradable polymerscrystallinitydynamic mechanical analysis (DMA)miscibilityplasticizationpoly(ethylene glycol) (PEG)polylactic acid (PLA)thermorheologytransient networkMore Related Videos
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