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SPAN Résumé de rapport

Project ID: G5RD-CT-2001-00568
Financé au titre de: FP5-GROWTH
Pays: Greece

Polymeric blends with antimicrobial and /or antifouling properties

Polymeric blends with antimicrobial and /or antifouling properties: active phosphonium ions containing oligomers were incorporated into different polymeric matrixes. The resulting blends exhibit pronounced antimicrobial activity.

Dispersion of the active phosphonium salt containing oligomers or polymers into a polymeric matrix resulted in materials with antimicrobial activity. Polymeric matrixes such as polyethylene, polypropylene or polyamides were used. The percentage of the active compound varied between 1 to 10%. All the blends were characterized with respect to their mechanical and thermal properties. Screening of the mechanical properties was based on the elongation at break, which is a sensitive indicator of the mechanical integrity. In the case of polyethylene, HDPE was used as matrix and blends with up to 7% polyester type oligomer containing phosphonium salt gave acceptable mechanical properties. In the case of polypropylene even with 3% oligomer the mechanical properties were very poor. In this case improved mechanical properties were obtained with 3% sulfonated polystyrene phosphonium salts. Both HDPE and PP blend compositions were tested with respect to their antifouling and antimicrobial activity.

The antimicrobial tests were performed according to the dynamic method, (Shake Flask method, ASTM E2149-01), for the determination of the antimicrobial activity of immobilized Antimicrobial Agents under dynamic contact conditions.

The test micro organisms used, were:
- X Esterichia Coli-CECT 239;
- X Staphilococcus aureus-CECT 516 ;
- X Aspergillus niger CECT-1394;
- X Candida albicans CECT-2574.

The results have shown that highly active materials were obtained in most cases. More specifically, the HDPE containing 3 wt% of the polyester type phosphonium oligomer showed a logarithmic reduction of 3 or even more for all the used microorganisms after 28 days. For the polypropylene compositions with 3-wt% of the polyester oligomer containing phosphonium salts, high activity was also obtained as supported by a logarithmic reduction of 3, for all the microorganisms used.

The sulfonated polystyrene phosphonium salt blend composition showed activity only against staphylococcus. However this composition retains the best antifouling activity as defined from using preliminary laboratory bioassays. The field tests concerning the antifouling activity of the polypropylene compositions are currently in progress.

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Joannis KALLITSIS, (Professor, Vice Chairman of the department)
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