New polymeric composites based on poly(ε-caprolactone) and layered double hydroxides containing antimicrobial species

TitleNew polymeric composites based on poly(ε-caprolactone) and layered double hydroxides containing antimicrobial species
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2009
AuthorsCostantino, U., Bugatti V., Gorrasi G., Montanari F., Nocchetti M., Tammaro Loredana, and Vittoria V.
JournalACS Applied Materials and Interfaces
Keywords2, 4 dichlorobenzoic acid, 4-dichlorobenzoic acid, Absorption spectroscopy, Active packaging, Anion exchange, Anti-Infective Agents, Anti-microbial activity, Anti-microbial tests, antiinfective agent, Antimicrobial property, Aromatic ring substituents, article, bacterial count, Ball milling, Benzoate derivative, Benzoates, benzoic acid derivative, Biodegradable polymers, Caprolactone, cell proliferation, Chemical compositions, chemistry, Chlorobenzoates, chlorobenzoic acid derivative, Chromatographic analysis, Colony Count, Composites, Counter anions, Crystal packings, Dichlorobenzoate, Differential scanning calorimetry, Differential thermal analysis, Diffraction, drug effect, Filled polymers, Fillers, Fourier Transform Infrared, Fourier transforms, High-energy ball milling, Host-guests, Hot pressing, Hydrogen, Hydrogen bond networks, Hydrogen bonds, hydroxybenzoic acid derivative, Hydroxybenzoic Acids, infrared spectroscopy, Inorganic layers, Intercalation, Intercalation compounds, IR absorption spectroscopy, Layered double hydroxides, Micro-composites, Microbial, Microorganisms, Model structures, nanocomposite, Nanocomposites, Negative ions, polycaprolactone, polyester, Polyesters, Polymer films, Polymer matrix composites, Polymeric composites, Polymeric films, Polymeric matrices, powder diffraction, Powder X ray diffraction, Pure culture, Reinforced plastics, Saccharomyces cerevisiae, Scanning electron microscopy, Spectroscopy, Structural models, Temperature, thermogravimetry, Van der waals, Van der Waals forces, X ray diffraction, X ray diffraction analysis, Yeast

Benzoate (Bz), 2,4-dichlorobenzoate (BzDC), and p- and o-hydroxybenzoate (p- and o-BzOH) anions with antimicrobial activity have been intercalated into [Zn 0.65Al 0.35(OH) 2](NO 3) 0.35·0.6H 2O, layered double hydroxide (LDH), via anion-exchange reactions. The composition of the obtained intercalation compounds, determined by chemical, thermogravimetric, and ion chromatographic analyses, indicates that benzoate and benzoate derivative anions replace the nitrate counteranions, almost completely. Information on the interactions of the intercalated anions with the inorganic layer have been obtained from Fourier transform IR absorption spectroscopy and powder X-ray diffraction of the samples. It has been found that both the nature and the position of the aromatic ring substituents affect the value of the basal distance and the host-guest hydrogen bond network. Knowledge of the chemical composition, basal distance, and van der Waals dimensions of the guests has finally allowed the proposal of structural models of the intercalation compounds that have been used as fillers of poly(caprolactone), a biodegradable polymer. Films of polymeric composites were obtained by hot-pressing the powders of polymer and filler previously milled by a high-energy ball milling procedure. X-ray diffraction analysis and optical and scanning electron microscopy of the composites indicate that the LDH samples containing BzDC anions are delaminated into the polymeric matrix, whereas those containing p-BzOH anions maintain for the most part the crystal packing and give rise to microcomposites. Intermediate behavior was found for LDH modified with Bz and o-BzOH anions because exfoliated and partly intercalated composites were obtained. Preliminary antimicrobial tests indicate that the composites are able to inhibit the Saccharomyces cerevisiae growth of 40% in comparison with the growth in a pure culture medium. The composites can be studied as the model for "active packaging" systems because of the antimicrobial properties of the anions anchored to the LDH layer. © 2009 American Chemical Society.


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