Ternary melt blends of poly(lactic acid)/poly(vinyl alcohol)-chitosan

• A new process for chitosan containing melt blends is proposed.
• Chitosan-poly(vinyl alcohol) (PVA)/poly(lactic acid) (PLA) melt blends were prepared.
• Chitosan-PVA solution blends were incorporated into PLA by melt processing.
• Glycerol was used as a common plasticizer for the three polymers.
• PVA-chitosan phase morphology was dependent on blending conditions.

Chitosan has aroused considerable interest because of its antimicrobial activity and biocompatibility and its use in functional blends with antimicrobial properties is growing, but it is still very limited since it cannot be melted under normal conditions and there is some doubt about the actual morphology of the purported blends. Here, we described a novel technique for melt processing chitosan in a blend with poly(lactic acid) and poly(vinyl alcohol), the latter being used as compatibilizing agent and the entire system being plasticized with a mutual plasticizer, glycerol. Blends were clear and the image of the brittle fracture surfaces shows a chitosan/PVA dispersed phase, of size varying from 0.5 to 2.5 μm, in the PLA phase. This paper presents for the first time a melt blend in which the chitosan phase is not distributed as particles in a composite and opens a new field of investigation of functional bioactive polymer blends.

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