Search

Your search keyword '"Saraga, Federico"' showing total 16 results
Start Over Author "Saraga, Federico"
16 results on '"Saraga, Federico"'

6. New nitrogen-rich heterocycles for organo-modified bentonites as flame retardant fillers in epoxy resin nanocomposites

Author

Benelli, Tiziana, Mazzocchetti, Laura, D'Angelo, Emanuele, Lanzi, Massimiliano, Saraga, Federico, Sambri, Letizia, Franchini, Mauro Comes, and Giorgini, Loris

Subjects
Nanoparticles -- Usage, Fillers (Materials) -- Usage, Heterocyclic compounds -- Usage, Flame retardants -- Chemical properties -- Production processes, Engineering and manufacturing industries, Science and technology
Abstract

New flame retardant organo-modified bentonites, based on nitrogen-containing compounds were synthesized via an ion exchange process starting from pristine bentonite with acidified 6-(4-butylphenyl)-1,3,5-triazine-2,4-diamine (BFTDA) and 11-amino-N-(pyridine-2yl)undecanamide (APUA). The amount of nitrogen rich organic modifier in the obtained organoclays (Bento-BFTDA and BentoAPUA) determined by TGA is around 0.4 mmol/g for both samples. With the aim to study the effect of these additives on a commercial epoxy resin, nanocomposites containing 3 and 5 wt% of the nanofillers were prepared by solventless addition to the epoxy resin formulation. For the sake of comparison similar nanocomposites with plain unmodified bentonite were produced. The nanocomposite's thermo-mechanical properties of all the produced samples were measured and they resulted slightly improved or practically unaffected. Finally, when the flame behavior was assessed in the cone-calorimeter, an encouraging decrease of 17% in the peak heat released rate (pHRR) was obtained at 3 wt% loading level with Bento-APUA. These promising results suggest that the APUA modified organoclay, prepared with low cost reactants and mild reaction conditions, might efficiently act as a flame retardant., INTRODUCTION In the last century, polymeric materials have greatly changed the world we live in, joining or replacing traditional metallic and natural materials. Composite materials, in particular, took steel and [...]

Published
2017
Full Text
View/download PDF

9. Quantitative inspection of grain‐scale chemical inhomogeneities in high‐entropy AlB2‐type transition metal diborides.

Author

Monteverde, Frédéric, Saraga, Federico, Gaboardi, Mattia, Feng, Lun, Hilmas, Gregory, and Fahrenholtz, William

Subjects
*SYNCHROTRON radiation, *SOLID solutions, *CHEMICAL energy, *ELECTRON microscopy, *ANALYTICAL chemistry
Abstract

The chemical homogeneity of single phase high‐entropy AlB2‐type Ti‐Zr‐Hf‐Ta‐TM diboride (TM = Cr, V, W, Mo), as well as Ti‐Zr‐Hf‐Mo‐W solid solutions was investigated using a new method based on the comparative examination of information provided by electron microscopy and structural parameters. The study of the densification behavior was accomplished, and strong correlations among densification rate‐grain coarsening‐long range chemical randomization were found. High‐resolution synchrotron radiation X‐ray diffraction supported by grain‐scale chemical analyses by energy dispersive spectroscopy indicated that homogenization of the metals was incomplete, with direct impact on the refined lattice μ‐strain. The chemical inhomogeneity was on the same length scale as the grain size, which makes it hardly detectable by typical chemical mapping using energy dispersive spectroscopy. Based on this analysis, the resulting μ‐strain broadening is not an intrinsic property of the material, but strongly depends on its processing history. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

11. Anisotropic thermal expansion in high-entropy multicomponent AlB2-type diboride solid solutions

Author

Monteverde, Frédéric, Gaboardi, Mattia, Saraga, Federico, Feng, Lun, Fahrenholtz, William, and Hilmas, Gregory

Abstract

High-entropy (HE) ultra-high temperature ceramics have the chance to pave the way for future applications propelling technology advantages in the fields of energy conversion and extreme environmental shielding. Among others, HE diborides stand out owing to their intrinsic anisotropic layered structure and ability to withstand ultra-high temperatures. Herein, we employed in-situhigh-resolution synchrotron diffraction over a plethora of multicomponent compositions, with four to seven transition metals, with the intent of understanding the thermal lattice expansion following different composition or synthesis process. As a result, we were able to control the average thermal expansion (TE) from 1.3 × 10−6to 6.9 × 10−6K−1depending on the combination of metals, with a variation of in-plane to out-of-plane TE ratio ranging from 1.5 to 2.8.

Published
2023
Full Text
View/download PDF

12. Sintesi di nanoparticelle polimeriche basate su acido(D,L-lattico-co-glicolico) per applicazioni in nanomedicina

Author

Saraga, Federico, thesis supervisor: Comes Franchini, Mauro, Saraga, Federico, and thesis supervisor: Comes Franchini, Mauro

Abstract

Questo lavoro di tesi rientra nel progetto europeo SaveMe, al quale partecipa il gruppo di ricerca del dipartimento di chimica organica nel quale ho svolto l’attività di tirocinio. Obiettivo finale di tale progetto è la sintesi di nanoparticelle a base di PLGA (acido poli(D,L-lattico-co-glicolico)) superficialmente funzionalizzate con biomolecole, per l’impiego nel trattamento e nella diagnosi del cancro al pancreas. L’obiettivo da raggiungere nel primo anno di ricerca per il mio gruppo era la sintesi delle nanoparticelle centrali (core nanosystems). Nel presente lavoro sono quindi riportati i metodi di sintesi di polimeri derivati da PLGA e suoi copolimeri con PEG (polietilenglicole) aventi vari gruppi funzionali terminali: acidi idrossamici, amminici e acidi carbossilici. I polimeri sintetizzati sono stati caratterizzati tramite test colorimetrici qualitativi, 1H-NMR, 13C-NMR, spettrometria IR e TGA. Sono state sintetizzate nanoparticelle polimeriche (PNPs), con le tecniche Oil/Water (O/W) e nanoprecipitazione (NP), basate sui polimeri ottenuti, aventi quindi funzioni acide, idrossamiche ed amminiche sulla superficie. Su queste PNPs è stato effettuata una decorazione superficiale con nanoparticelle metalliche di maghemite (CAN-Maghemite). Le nanoparticelle polimeriche sono state caratterizzate tramite DLS e delle PNPs decorate sono state ottenute immagini TEM. Sono riportati inoltre i test di viabilità cellulare delle nanoparticelle ottenute.

13. Sintesi di nanoparticelle polimeriche basate su acido(D,L-lattico-co-glicolico) per applicazioni in nanomedicina

Author

Saraga, Federico, thesis supervisor: Comes Franchini, Mauro, Saraga, Federico, and thesis supervisor: Comes Franchini, Mauro

Abstract

Questo lavoro di tesi rientra nel progetto europeo SaveMe, al quale partecipa il gruppo di ricerca del dipartimento di chimica organica nel quale ho svolto l’attività di tirocinio. Obiettivo finale di tale progetto è la sintesi di nanoparticelle a base di PLGA (acido poli(D,L-lattico-co-glicolico)) superficialmente funzionalizzate con biomolecole, per l’impiego nel trattamento e nella diagnosi del cancro al pancreas. L’obiettivo da raggiungere nel primo anno di ricerca per il mio gruppo era la sintesi delle nanoparticelle centrali (core nanosystems). Nel presente lavoro sono quindi riportati i metodi di sintesi di polimeri derivati da PLGA e suoi copolimeri con PEG (polietilenglicole) aventi vari gruppi funzionali terminali: acidi idrossamici, amminici e acidi carbossilici. I polimeri sintetizzati sono stati caratterizzati tramite test colorimetrici qualitativi, 1H-NMR, 13C-NMR, spettrometria IR e TGA. Sono state sintetizzate nanoparticelle polimeriche (PNPs), con le tecniche Oil/Water (O/W) e nanoprecipitazione (NP), basate sui polimeri ottenuti, aventi quindi funzioni acide, idrossamiche ed amminiche sulla superficie. Su queste PNPs è stato effettuata una decorazione superficiale con nanoparticelle metalliche di maghemite (CAN-Maghemite). Le nanoparticelle polimeriche sono state caratterizzate tramite DLS e delle PNPs decorate sono state ottenute immagini TEM. Sono riportati inoltre i test di viabilità cellulare delle nanoparticelle ottenute.

14. Improved aero-thermal resistance capabilities of ZrB2-based ceramics in hypersonic environment for increasing SiC content

Author

Raffaele Savino, Anselmo Cecere, Frédéric Monteverde, Diletta Sciti, Federico Saraga, Stefano Mungiguerra, Mungiguerra, Stefano, Cecere, Anselmo, Savino, Raffaele, Saraga, Federico, Monteverde, Frédéric, and Sciti, Diletta

Subjects
Materials science, C. Thermodynamic diagrams, 020209 energy, General Chemical Engineering, Thermal resistance, Oxide, 02 engineering and technology, A. Ceramic, Corrosion, chemistry.chemical_compound, Tetragonal crystal system, C. High temperature corrosion, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Cubic zirconia, Ceramic, Composite material, A. Zirconium, B. SEM, Borosilicate glass, C. Oxidation, General Chemistry, 021001 nanoscience & nanotechnology, A. Ceramic, A. Zirconium, B. SEM, C. High temperature corrosion, C. Oxidation, C. Thermodynamic diagrams, chemistry, visual_art, Temperature jump, visual_art.visual_art_medium, 0210 nano-technology
Abstract

The effects of SiC content on aero-thermal resistance capabilities of ZrB2-xSiC-5Y2O3 ceramics (x = 5,10,15,18.5 vol%) in atmospheric re-entry environment were investigated, exposing four hot-pressed button-like specimens to an arc-heated plasma wind tunnel supersonic flow (enthalpy up to 20 MJ/kg). As x increased, the maximum steady-state surface temperature decreased. A 400 K-spontaneous temperature jump was observed on the ZrB2-5SiC-5Y2O3 front surface, with final temperature exceeding 2750 K. The oxide scale consisted in Y-stabilized tetragonal/cubic zirconia, borosilicate glass, and Y2Si2O7 in minor amount. SEM-EDS documented the microstructural differences for varying x, correlating the aero-thermal behavior, including the temperature jump, to borosilicate glass durability.

Published
2021
Full Text
View/download PDF

15. New nitrogen-rich heterocycles for organo-modified bentonites as flame retardant fillers in epoxy resin nanocomposites

Author

Federico Saraga, Loris Giorgini, Tiziana Benelli, Laura Mazzocchetti, Letizia Sambri, Massimiliano Lanzi, Emanuele D’Angelo, Mauro Comes Franchini, Benelli, Tiziana, Mazzocchetti, Laura, D'Angelo, Emanuele, Lanzi, Massimiliano, Saraga, Federico, Sambri, Letizia, COMES FRANCHINI, Mauro, and Giorgini, Loris

Subjects
chemistry.chemical_classification, Nanocomposite, Materials science, flame retardant, Polymers and Plastics, polymer, 02 engineering and technology, General Chemistry, Polymer, Epoxy, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Nitrogen rich, chemistry, visual_art, Materials Chemistry, visual_art.visual_art_medium, Composite material, 0210 nano-technology, Fire retardant
Abstract

New flame retardant organo-modified bentonites, based on nitrogen-containing compounds were synthesized via an ion exchange process starting from pristine bentonite with acidified 6-(4-butylphenyl)−1,3,5-triazine-2,4-diamine (BFTDA) and 11-amino-N-(pyridine-2yl)undecanamide (APUA). The amount of nitrogen rich organic modifier in the obtained organoclays (Bento-BFTDA and Bento-APUA) determined by TGA is around 0.4 mmol/g for both samples. With the aim to study the effect of these additives on a commercial epoxy resin, nanocomposites containing 3 and 5 wt% of the nanofillers were prepared by solventless addition to the epoxy resin formulation. For the sake of comparison similar nanocomposites with plain unmodified bentonite were produced. The nanocomposite's thermo-mechanical properties of all the produced samples were measured and they resulted slightly improved or practically unaffected. Finally, when the flame behavior was assessed in the cone-calorimeter, an encouraging decrease of 17% in the peak heat released rate (pHRR) was obtained at 3 wt% loading level with Bento-APUA. These promising results suggest that the APUA modified organoclay, prepared with low cost reactants and mild reaction conditions, might efficiently act as a flame retardant.

Published
2017

16. Organo-modified bentonites as new flame retardant fillers in epoxy resin nanocomposites

Author

Federico Saraga, Emanuele D’Angelo, Laura Mazzocchetti, Letizia Sambri, Mauro Comes Franchini, Loris Giorgini, Tiziana Benelli, Benelli, Tiziana, D'Angelo, Emanuele, Mazzocchetti, Laura, Saraga, Federico, Sambri, Letizia, Comes Franchini, Mauro, and Giorgini, Loris

Subjects
Thermogravimetric analysis, Materials science, Nanocomposite, Ion exchange, nanocomposite, Epoxy, organoclays, epoxy resin, Flame retardant, visual_art, Bentonite, visual_art.visual_art_medium, Organoclay, Composite material, Flammability, Fire retardant
Abstract

The present work deals with two organophilic bentonites, based on nitrogen-containing compounds: these organoclays were synthesized via an ion exchange process starting from pristine bentonite with 6-(4-butylphenyl)-1,3,5-triazine-2,4-diamine (BFTDA) and 11-amino-N-(pyridine-2yl)undecanamide (APUA) and then used for the production of epoxy-based flame retardant nanocomposites. The amount of organic modifier in the organoclays Bento-BFTDA and Bento-APUA was determined with a TGA analysis and is around 0.4mmol/g for both samples. The effect of the organoclays on a commercial epoxy resin nanocomposite’s thermo-mechanical and flammability properties was investigated. Composites containing 3wt% and 5wt% of the nanofillers were prepared by solventless addition of each organoclay to the epoxy resin, followed by further addition of the hardener component. For the sake of comparison a similar nanocomposite with the plain unmodified bentonite was produced in similar condition. The nanocomposites’s thermo-mechanical properties of all the produced samples were measured and they resulted slightly improved or practically unaffected. On the contrary, when the flame behaviour was assessed in the cone-calorimeter, an encouraging decrease of 17% in the peak heat released rate (pHRR) was obtained at 3wt% loading level with Bento-APUA. This is a promising result, assessing that the APUA modified organoclay might act as flame retardant.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results