Antimicrobial polyamide 11 (PA-11) films containing low-cost, thermally stable and water resistant polymeric biocide polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS) have been obtained by compression moulding. The structure of the modified PA-11 films containing from 3 to 10 wt% of PHMG-DBS was characterized using Raman and FTIR spectroscopy and atomic force microscopy (AFM). The surface properties were evaluated both by contact angle and contactless inductive method. The introduction of PHMG-DBS into PA-11 films was found to increase positive surface charge density to 5.5Á10 -11 C/cm 2 for 10 wt% of PHMG-DBS. Antibacterial activity of PA-11/ PHMG-DBS films against both Gram-positive (Escherichia coli) and Gram-negative (Bacillus subtilis) bacteria was demonstrated for films containing from 5 to 7 wt% of polymeric biocide. According to thermal investigations data, PA-11/ PHMG-DBS composite has excellent thermal stability to at least 390°C both in air and in argon atmosphere which indicates on its availability for the melt processing by common methods. It has also been found that polymeric biocide is highly resistant to leaching from PA-11 film.
Four water immiscible ionic liquids (ILs): 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-heptyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium tetrafluoroborate and 1-dodecyl-3-methylimidazolium tetrafluoroborate have been synthesized. Polycarbonate (PC) films containing ILs were prepared by solvent casting from methylene chloride solutions. Scanning electron microscopy measurements showed the high homogeneity of PC/IL films with the IL content up to 4 wt %. The tendency to IL aggregation was observed for polymeric films with higher IL content (5%). PC/IL composites were found to have the reduced thermal decomposition temperature under both an air and a nitrogen atmosphere in comparison with the neat PC. The effect of IL content on the antimicrobial activity of PC films against Escherichia coli bacteria was studied. Pronounced antimicrobial efficacy was revealed for PC/IL films for all studied ILs starting from 3 wt % of IL.
There were two errors in the article abstract. Instead of Gram-positive (Escherichia coli) it should read Gram-negative (Escherichia coli); instead of Gramnegative (Bacillus subtilis) it should read Gram-positive (Bacillus subtilis). The authors were solely responsible for these errors and regret any confusion they may have caused.The online version of the original article can be found under
The growth-promoting activity of poly(DEG-GH) was studied using a test-culture of winter wheat Podolianka. Wheat seeds were soaked in water solutions of cationic polymer for 1 h, placed into Petri dishes and germinated on filters, moistened with distilled water. After seven days, the length of shoots of the seedlings, soaked in poly(DEG-GH) solutions with the concentration of 0.001 % and 0.01 %, was higher compared to control samples (by 6.7 % and 17.8 %, respectively). The maximum increase in the length of seedling roots (14.5 % compared to the control) was established for the lowest cationic polymer concentration of 0.001 %. The concentration of poly(DEG-GH) of 0.1 % inhibited the growth of roots and shoots by 28 % and 18 %, respectively. Thus, the cationic polymer poly(DEG-GH) demonstrates growth-promoting activity on wheat seedlings in the low concentration range of 0.001–0.01 %.
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