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Antimicrobial Activity, Structural, Crystallographic and Thermal Characteristics of Alpha-Titanium Phosphate Promoted by Silver Ions

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Materials Sciences and Applications 2024年第8期15卷 253-269页

作者： Enzo Erbisti Garcia Agnes Maria Cupertino Fernandes Araujo gerson alberto valencia albitres Daniela de França da Silva Freitas Danielle Mattos Mariano Carlos Magno Fialho Soares Sibele Piedade Cestari Marco Antônio Lemos Miguel Luis Claudio Mendes Institute of Macromolecules Professora Eloisa Mano Federal University of Rio de Janeiro Avenida Horacio Macedo 2030 Centro de Tecnologia Bloco J Ilha do Fundo Rio de Janeiro Brazil Institute of Microbiology Paulo de Ges Federal University of Rio de Janeiro Centro de Ciencias da Saude Bloco I Ilha do Fundo Rio de Janeiro Brazil Innovation in Polymer Engineering (PIEP) University of Minho Guimares Portugal

The recent global spread of the pandemic underscores the necessity of seeking new materials effective against microorganisms. Nanotechnology offers avenues for developing multifunctional materials. In this study, alpha-titanium phosphate (α-TiP) nanoparticles were synthesized and treated with silver salt to enhance their antimicrobial properties. The physicochemical characteristics and antimicrobial activity were evaluated. It was revealed by X-ray diffraction analysis that the structural integrity of α-TiP was influenced by ethylenediamine and silver ions. Distinct degradation profiles for each chemical modification were shown by thermogravimetric analysis. Infrared spectroscopy detected shifts and new absorption peaks in the spectra depending on the type of modification. Energy dispersive spectroscopy confirmed the disaggregation of α-TiP galleries following the addition of silver salt, which increased their effectiveness against microorganisms. Notably, only the sample treated with silver ions exhibited antimicrobial action. Antimicrobial activity was tested against the bacteria of medical importance Escherichia coli, Salmonella Enteritidis, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Listeria momocytogenes and the yeast Candida albicans. All microorganisms were inhibited by sample containing silver. Minor inhibition was observed against the Gram-positive bacteria L. monocytogenes and Bacillus cereus, while the greatest inhibition occurred against the fungus (yeast) C. albicans. The results revealed a potential application of the nanoparticles for control of microorganisms in public health.

关键词： Titanium Phosphate Silver Nitrate Antimicrobial Action

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Zinc and Silver Salts-Containing Lamellar Titanium Phosphate: A Multifunctional Filler

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Materials Sciences and Applications 2022年第6期13卷 366-388页

作者： Enzo Erbisti Garcia gerson alberto valencia albitres Daniela França Silva Freitas Danielle Mattos Mariano Luis Cláudio Mendes Universidade Federal do Rio de Janeiro Instituto de Macromoléculas Professora Eloisa Mano Avenida Horácio Macedo Rio de Janeiro Brazil

Zinc and silver compounds have been studied because they have ultraviolet light barrier properties and bactericidal action, respectively. Materials with multifunctional characteristics have been sought to produce polymeric nanocomposites. In this work, the chemical modification of titanium phosphate (TiP) was carried out through a route with successive intercalations. TiP was synthesized and consecutively pre-expanded with ethylamine and pyromellitic acid. Then it was modified with zinc acetate and silver nitrate. The final product was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, wide-angle X-ray diffractometry, field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and thermogravimetry. Infrared revealed dislocation and appearance of bands according to the intercalating agent. Inorganic salts interfered in the crystallization and melting processes of pyromellitic acid. Vanishing of the TiP hkl plane and variation and appearance of new crystallographic planes at low diffraction angles induced intercalation. SEM showed agglomerated structures. New thermal degradation events at higher temperatures endorsed the formation of zinc and silver carboxylate salts. We concluded that a new miscellaneous and multifunctional matter was achieved.

关键词： Titanium Phosphate Intercalation Pyromellitic Acid Zinc Acetate Silver Nitrate Ethylamine

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Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

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Materials Sciences and Applications 2023年第6期14卷 346-361页

作者： Danielle Mattos Mariano Daniela França Silva Freitas gerson alberto valencia albitres Luis Claudio Mendes Maria Ines Bruno Tavares Instituto de Macromoléculas Professora Eloisa Mano Centro de Tecnologia Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm-1 due to the formation of ionic specie PO? +NH3-[C-(H)(CH3)-CH2-O-(C-(H)(CH3)-CH2-O)8-(CH2-CH2-O-CH3)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.

关键词： Lamellar Zirconium Phosphate Jeffamine Nano-Zinc Oxide Intercalation

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Nanocellulose: Effect on Thermal, Structural, Molecular Mobility and Rheological Characteristics of Poly(Butylenes Adipate-Co-Butylene Terephthalate) Nanocomposites

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Materials Sciences and Applications 2022年第4期13卷 249-277页

作者： gerson alberto valencia albitres Francisco Pereira Araujo Junior Daniela França Silva Freitas Danielle Mattos Mariano Maria Ines Bruno Tavares Luis Claudio Mendes Universidade Federal do Rio de Janeiro Instituto de Macromoléculas Professora Eloisa Mano Rio de Janeiro Brazil

The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this work aimed to study the effect of adding nanocellulose (nCE) with 1, 3, and 5 wt.% on poly(butylene adipate-co-butylene terephthalate) (PBAT). Thermal, structural, relaxometric, and rheological assessments were carried out. Quantitative evaluation of PBAT copolymer by high field NMR revealed 56.4 and 43.6 m.% of the butylene adipate and butylene terephthalate segments, respectively. WAXD measurement on the deconvoluted diffraction patterns identified that nCE was a mixing of Cellulose I and Cellulose II polymorph structures. At any composition, nanocellulose interfered with the PBAT crystallisation process. Also, a series of new PBAT crystallographic planes appeared as a function of nanocellulose content. PBAT hydrogen molecular relaxation varied randomly with nanocellulose content and had a strong effect on the hydrogen relaxation. PBAT cold crystallisation and melting temperatures (Tcc and Tm) were almost unchangeable. Although Tcc did not change during polymer solidification from PBAT molten state, the sample’s degree of crystallinity varied with composition through the transcrystallization phenomenon. Nanocomposite thermal stability decreased possibly owing to the catalytic action of sulfonated amorphous cellulose chains. For the sample with 3 wt.% of nanocellulose, the highest values of complex viscosity and storage modulus were achieved.

关键词： Nanocellulose Poly(Butylene Adipate-Co-Butylene Terephthalate) Molecular Relaxation Nanocomposite

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