Abstract
Films from colloidal suspensions of cationic polyelectrolyte complexes of xylan (Xyl) and chitosan (Ch) were formed and characterized by measuring: oxygen and water vapor barrier properties, solubility, and mechanical properties. High xylan content (Xyl/Ch mass ratio: from 70/30 to 85/15) was used, and a low amount of plasticizer (10 wt% glycerol) was always added. At 50% relative humidity (RH), all films had promising oxygen barrier properties (<0.3 μm cm 3/day m 2 kPa) and good mechanical properties for applications such as food packaging (stress at break of 10 MPa and strain at break of 12.2% for 70/30 Xyl/Ch film). All films showed a moderate water vapor transmission rate: 19.6–21.3 g/(h m 2). Although solubility was relatively high (26.5–35.4%), the integrity of the films was maintained after immersion in pH 5.0 buffer solution for 24 h. The 70/30 film was the most transparent, uniform, and deformable of the formulations evaluated, showing low crystallinity according to X-ray diffraction results. Dynamic mechanical analysis revealed a high correlation between its viscoelastic behavior and changes in RH (from 0 to 80% RH). Studies conducted using an agar disc diffusion protocol showed antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria only in the contact area under the film discs.
Original language | English |
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Pages (from-to) | 4393-4403 |
Journal | Cellulose |
Volume | 24 |
Issue number | 10 |
Early online date | 29 Jul 2017 |
DOIs | |
Publication status | Published - 2017 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Natural polyelectrolyte complexes
- Barrier properties
- Relative humidity effect
- Antimicrobial effect
- Mechanical properties