Concetto Puglisi - Academia.edu (original) (raw)

Papers by Concetto Puglisi

Research paper thumbnail of Molecular Weight Determination and Structural Analysis in Polydisperse Polymers by Hyphenated Gel Permeation Chromatography/Matrix-Assisted Laser Desorption Ionization—Time of Flight Mass Spectrometry

International Journal of Polymer Analysis and Characterization, Mar 1, 1997

Research paper thumbnail of Synthesis and characterization of poly(ether ketone)/poly(ether sulfone) alternating and sequential copolymers by electrophilic reactions

Macromolecular Chemistry and Physics, Mar 1, 1996

Bis(b-naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of b-naphthol with 2,6-difluorob... more Bis(b-naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of b-naphthol with 2,6-difluorobenzonitrile in N-methyl-2-pyrrolidone (NMP) in the presence of KOH and K 2 CO 3. Poly(ether ketone ether ketone ketone)(PEKEKK) /poly(ether ether ketone ketone) (PEEKK) copolymers containing naphthalene and pendant cyano groups were obtained by electrophilic Friedel-Crafts polycondensation of terephthaloyl chloride (TPC) with varying mole proportions of 4,4 0-diphenoxybenzophenone (DPOBP) and 2,6-bis(b-naphthoxy)benzonitrile (BNOBN) using 1,2dichloroethane (DCE) as solvent and NMP as Lewis base in the presence of anhydrous AlCl 3. The resulting polymers were characterized by various analytical techniques, such as FTIR, DSC, TG, and WAXD. The results indicated that the crystallinity and melting temperature of the polymers decreased with increase in concentration of the BNOBN units in the polymer, the glass transition temperature of the polymers increased with increase in concentration of the BNOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 536 C in N 2 atmosphere. The copolymers have good resistance to acidity, alkali, and organic solvents. Because of the melting temperature (T m) depression with increase in the BNOBN content in the reaction system, the processability of the resultant coplymers could be effectively improved. V

Research paper thumbnail of Application of size exclusion chromatography matrix-assisted laser desorption/ionization time-of-flight to the determination of molecular masses in polydisperse polymers

Rapid Communications in Mass Spectrometry, May 15, 1998

ABSTRACT The determination of molecular mass (MM) data for polydisperse polymers by size exclusio... more ABSTRACT The determination of molecular mass (MM) data for polydisperse polymers by size exclusion chromatography matrix assisted laser desorption/ionization time-of-flight (SEC/MALDI-TOF) involves the fractionation of samples through an analytical SEC. Selected fractions are then analysed by MALDI-TOF and the mass spectra of these nearly monodisperse samples allow the determination of Mn and Mw averages. To test the reliability of the molecular mass estimates by the SEC/MALDI-TOF method, a sample of polymethylmethacrylate (PMMA), two samples of polydimethylsiloxane (PDMS), and four samples of copolyesters, all polydisperse, were analysed. The results show that the molecular mass values of PMMA fractions obtained by MALDI-TOF are coincident with those obtained using the SEC calibration plots obtained with anionic PMMA standards. In the case of the two polydimethylsiloxanes (PDMS1 and PDMS2: linear and cyclic, respectively), two slightly differing SEC calibration plots were obtained, reflecting the different structures of the polymer chains of the two samples. The SEC traces of four copolyesters were obtained in tetrahydrofuran and CHCl3. Data on MM, MM distribution solvent effects and copolymer composition are reported. © 1998 John Wiley & Sons, Ltd.

Research paper thumbnail of Synthesis and Characterization of Linear Hyperbranched PBA Block Copolymers, as Potential Polymeric Plasticizers

V INTERNATIONAL CONFERENCE ON TIMES OF POLYMERS (TOP) AND COMPOSITES, 2010

Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a on... more Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a one-pot synthesis procedure and well characterized by MALDI-TOF mass spectrometry, H-NMR and SEC tools, to obtain reliable information on its chemical composition and molar mass distribution.

Research paper thumbnail of An innovative approach for the chemical structural characterization of poly(styrene 4-vinylpyridine) copolymers by matrix-assisted laser desorption/ionization time of flight mass spectrometry

Journal of Applied Polymer Science, Aug 29, 2018

ABSTACT: Poly(styrene-co-4-vinylpyridine) random copolymers with different molar composition were... more ABSTACT: Poly(styrene-co-4-vinylpyridine) random copolymers with different molar composition were synthesized by nitroxidemediated controlled-radical polymerization using 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) as a mediator. We record the matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) spectra under various conditions, and we find (at last) that they show mostly intact ions [using 2(-4-hydroxyphenylazo-)benzoic acid as MALDI matrix]. Spectra are highly resolved, and thus they allow for the determination of all end-groups, even some less-abundant ones. Spectra are dominated by intact "dormant" copolymer chains terminated with TIPNO at one end and with (4-Bromo-phenyl)ethyl group (starting fragment) at the other one. Applying the mass analysis of copolymers (MACO) statistical model to the spectra, we show that the MACO/MALDI-TOF mass spectrometry (MS) analysis can be successfully applied to copolymers having a difference between the mass of the comonomers as small as 1 g mol −1 (the styrene and 4-vinylpyridine units are 104.15 and 105.15 g/mol, respectively), which results in overlapping isotopic patterns. The results are accurate: chemical composition evaluated by means of MS agrees with that calculated by 1 H-nuclear magnetic resonance, for all copolymers investigated. This analytical method allows to extract detailed information on the composition of the copolymer samples and their structure. Glass transition temperatures of copolymers were also determined by differential scanning calorimetry.

Research paper thumbnail of Molecularly imprinted polymer for selective adsorption of diclofenac from contaminated water

Chemical Engineering Journal, Jul 1, 2019

Abstract The presence of pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) ... more Abstract The presence of pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) in the aquatic environment represents a worldwide threat. NSAIDs are considered “emerging contaminants” of water since the traditional methods are not designed to efficiently remove them. Aiming to overcome the limits of the conventional wastewater treatment plants, we propose molecularly imprinted polymers (MIPs) as valid tools for selective adsorption and removal of these drugs from water. In particular, in this work, we have prepared diclofenac-selective MIP by a simple bulk polymerization process. After the characterization of the synthetized polymers, the binding abilities were evaluated in detail through the adsorption of diclofenac in aqueous solution and compared with the abilities of a corresponding non-imprinted polymer used as a reference. Thanks to the imprinting effect, the prepared MIP adsorbs with extreme selectivity its template molecule, i.e. the diclofenac. This effect was evaluated by testing the adsorption abilities towards different drugs, such as acetylsalicylic acid and trimethoprim. In addition, MIP reusability was demonstrated after a simple regeneration step. The strength of this work is due to the low cost synthesis of MIP and to its optimal performance of molecular recognition in water, differentially from many of the traditional MIPs, usually used with organic solvent. Such peculiarities make the material potentially applicable for water treatment on a large scale.

Research paper thumbnail of Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 1. End group and molar mass determination

Rapid Communications in Mass Spectrometry, Nov 30, 1999

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fra... more The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses. The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2. The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones. In agreement with theory, the ratio (M(cycle)/M(linear))(Ve) at a fixed elution volume was found to be 1.22, independent of the molar mass values. Copyright 1999 John Wiley & Sons, Ltd.

Research paper thumbnail of Separation and characterization of cyclic sulfides formed in the polycondensation of dibromoalkanes with aliphatic dithiols

Macromolecules, Nov 1, 1986

MS and GPC analyses are used to identify the cyclic oligomers formed in the polycondensation reac... more MS and GPC analyses are used to identify the cyclic oligomers formed in the polycondensation reactions of aromatic dithiols and dibromoalkanes leading to ar'omatic-aliphatic polysulfides. A correlation exists between the two sets of data obtained by these techniques. Mass spectra of the cyclic oligomers formed in the polymerization reactions are reported.

Research paper thumbnail of Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 2. Self-association due to phenol end groups

Rapid Communications in Mass Spectrometry, Nov 30, 1999

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fra... more The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses. The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2. The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones. In agreement with theory, the ratio (M(cycle)/M(linear))(Ve) at a fixed elution volume was found to be 1.22, independent of the molar mass values. Copyright 1999 John Wiley & Sons, Ltd.

Research paper thumbnail of Mechanism of thermal degradation of polyurethanes. Effect of ammonium polyphosphate

Macromolecules, Aug 1, 1984

The various pathways of degradation of polyurethane based on MDI and propoxylated trimethylol pro... more The various pathways of degradation of polyurethane based on MDI and propoxylated trimethylol propane were studied from the analysis of degradation gases sampled at various temperatures during the heating rise. From the beginning of degradation (25OOC) to 40O0C, we suggest that the main mechanism is the fracture of the polyurethane molecule into primary amine, carbon dioxide, and propenyl ether, the last leading to propene. Beyond this temperature, the mechanism may be reduced to a depolymerization process followed by radical breakdown of the polyol chain and by stripping and rearrangement of simple radicals, all of these giving the gaseous species obtained.

Research paper thumbnail of Molecular and Structural Characterization of Polydisperse Polymers and Copolymers by Combining MALDI-TOF Mass Spectrometry with GPC Fractionation

Macromolecules, Nov 1, 1995

Octafunctionalized spherosilsesquioxanes (Q 8 M 8 H), decorated with Si−H functions, could be use... more Octafunctionalized spherosilsesquioxanes (Q 8 M 8 H), decorated with Si−H functions, could be used to design, by coupling via hydrosilylation with α-methoxy-ω-undecenyl poly(ethylene oxide)s (PEOs), organic− inorganic nanocomposite structures. 1 H, 13 C, and 29 Si NMR; size exclusion chromatography; and Fourier transfrom infrared spectroscopy were used to follow the grafting reaction and determine the molar mass and the functionality of the different species. Hybrid star-shaped poly(ethylene oxide)s of precise molar mass and functionality could be isolated by fractional precipitation of the raw reaction product. Absolute molar masses of the purified star-shaped PEOs, calculated with the assumption of a functionality of 8, were comparable when measured by light scattering in methanol and by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Small-angle X-ray scattering was employed to determine their molecular and structural characteristics, representing the versatility and innovative aspect to this study. Both differential scanning calorimetry and optical microscopy were utilized to elaborate and analyze the thermal properties and crystallization, respectively, of the hybrid stars. Further ongoing work is being carried out currently to investigate and foresee the use of longer PEO branches onto the core.

Research paper thumbnail of Polyetherimide

John Wiley & Sons, Inc. eBooks, Nov 30, 2011

ABSTRACT

Research paper thumbnail of Exchange Reaction Mechanisms in the Reactive Extrusion of Condensation Polymers

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Oct 6, 2017

Research paper thumbnail of Surface evolution of polycarbonate/polyethylene terephthalate blends induced by thermal treatments

Applied Surface Science, 2003

Bisphenol-A polycarbonate (PC) and polyethyleneterephthalate (PET) blends are known to undergo, u... more Bisphenol-A polycarbonate (PC) and polyethyleneterephthalate (PET) blends are known to undergo, upon thermal treatment (melt mixing), exchange reactions leading to the formation of copolymers having a ®nal structure that is also affected by consecutive reactions involving CO 2 and ethylene carbonate losses. In this work we followed the evolution of the surface composition of this system during the melt mixing at 270 8C, both with and without catalysts, by means of time-of-¯ight secondary ion mass spectroscopy (ToF-SIMS). The static SIMS spectra obtained at different treatment times show the appearance of peaks related to newly formed structures and also the modi®cation of the relative intensities of peaks characteristic of both the initial constituents of the blend. From the variation of the relative intensities of peaks related to the bisphenol-A unit of PC and to the phthalate structure of PET, it is shown that after the ®rst stages of melt mixing the surface is PC enriched and that with the progressive formation of a random copolymer the phthalate units increase their concentration at the surface of the system. Hence, as ®nal result of the melt mixing process, the surface composition tends to re¯ect the relative amount of the repeating units in the bulk.

Research paper thumbnail of Polymer Blends Based on 1-Hexadecyl-3-methyl Imidazolium 1,3-Dimethyl 5-Sulfoisophthalate Ionic Liquid: Thermo-Mechanical, Surface Morphology and Antibacterial Properties

Polymers, Feb 16, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Bioaccumulation of trace elements in the sandhopper Talitrus saltator (Montagu) from the Ionian sandy coasts of Sicily

Ecotoxicology and Environmental Safety, Jul 1, 2016

The Ionian beaches of Sicily are of particular ecological interest because they include the basin... more The Ionian beaches of Sicily are of particular ecological interest because they include the basin of the largest active volcano in Europe and hosts both sites subject to natural protection constraints, as well as important industrial settlements. Consequently, the possibilities for these areas to become polluted are numerous. The sandhopper Talitrus saltator has proven to be a good bioindicator of contamination by numerous trace metals on some European coasts. Nevertheless, no data are available for the populations inhabiting the shores of the southern Mediterranean. Now, as metal accumulation has been shown to vary intraspecifically, the aim of this study was to evaluate trace metal accumulation in adults of T. saltator inhabiting Ionian coastal areas of Sicily and make an assessment of natural and anthropogenic metal pollution of this strip of coast. We also extended our survey to As, Co, Mo, Se, Sn and V never investigated before in this species. Significant differences in metal concentration among sites were found in both sand samples and amphipod tissues. The highest metal content was observed near the mouth of Simeto, the longest river of Sicily which collects waters coming from the volcanic territory of Mount Etna. The bioaccumulation of Cd, Cu, Hg and Zn in T. saltator is fully confirmed; it is also proven for As and Mo and assumed for Cr, Fe, Mn and V. Our outcomes let us to evaluate the prevailing influence of telluric contamination of the Ionian sandy shores of Sicily by trace metals. We also come to the conclusion that in the northern sites, pollution originates from volcanic emission while anthropogenic influence prevails in the southern ones.

Research paper thumbnail of The ground beetle Parallelomorphus laevigatus is a potential indicator of trace metal contamination on the eastern coast of Sicily

Ecotoxicology and Environmental Safety, 2017

Carabids are generally considered to be non-specialized predators, and they have been considered ... more Carabids are generally considered to be non-specialized predators, and they have been considered useful ecological indicators. They can play a key role in clarifying the route of contaminants in food webs because they are predators of small invertebrates and, in turn, part of the diet of several vertebrates. The Mediterranean species Parallelomorphus laevigatus, which so far has not been studied from an ecotoxicological point of view, is an excellent ecological indicator in sandy coastal environments. We investigated the accumulation of trace elements in Ionian populations of P. laevigatus and evaluated the transfer of metal through the food chain of the coastal ecosystem. We analyzed 15 metals, including 11 essential metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V and Zn) and four toxic metals (As, Cd, Hg and Pb). Significant differences were found in metal concentration in animal tissues among sites. Our results support the existence of defense mechanisms for the studied species. High values of As, Cd, Cr, Pb, Ni, and Hg detected in the beetles from the control site can be explained by both the emission sources from the nearby industrial plants and the intense agricultural activity. The present paper shows increasing Hg concentrations in the simplified trophic web of sandy beaches and confirms the capability of this pollutant to biomagnify. Moreover, the high value of biomagnification factor (BMF) points to the severe pollution level in this protected area.

Research paper thumbnail of Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with size-exclusion chromatographic fractionation for structural characterization of synthetic aliphatic copolyesters

Rapid Communications in Mass Spectrometry, Feb 7, 2006

We report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF... more We report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and off‐line coupling of size‐exclusion chromatography with MALDI‐TOFMS analysis (SEC/MALDI‐TOFMS) methods for the detailed characterization of poly[(R,S)‐3‐hydroxybutyrate‐co‐L‐lactic acid], P[(R,S)‐3HB‐co‐LA], and poly[(R,S)‐3‐hydroxybutyrate‐co‐ε‐caprolactone], P[(R,S)‐3HB‐co‐CL], copolymer samples which are expected to be used in special medical application as scaffolds for cartilage and soft tissue engineering. The novel copolyesters contained randomly distributed (R,S)‐3‐hydroxybutyrate structural units, were synthesized by transesterification of the corresponding homopolymers, i.e. atactic poly[(R,S)‐3‐hydroxybutyrate], a‐PHB, and poly(L‐Lactide) (PLLA) or poly(ε‐caprolactone) (PCL), respectively. The MS methods used for the characterization of the resulting polydisperse copolyester samples were supported by classical methods (NMR, SEC). The structures of individual copolyester macromolecules, including end‐group chemical structures, were established using initially MALDI‐TOFMS and then SEC/MALDI‐TOFMS. The compositions of the copolyesters were determined by two methods, namely based on 1H NMR and MALDI‐TOF spectra. The two sets of values showed good agreement. The sequence distribution was determined using the signal intensities of individual copolyester macromolecules, which appeared in MALDI‐TOF mass spectra. Furthermore, sequence analysis gave information about the degree of transesterification. The copolyesters synthesized, with only one exception, were demonstrated to be almost random, which implies that the ester‐ester exchange was close to completion. Copyright © 2006 John Wiley & Sons, Ltd.

Research paper thumbnail of Packaging effects on highly nutritional value beverage obtained by a mix of typical sicilian fruits in accelerated storage

Food Packaging and Shelf Life

Research paper thumbnail of Full Recycling and Re-Use of Bio-Based Epoxy Thermosets: Chemical and Thermomechanical Characterization of the Recycled Matrices

Polymers

High performances of thermosets deriving from their covalent intermolecular cross-link bonds resu... more High performances of thermosets deriving from their covalent intermolecular cross-link bonds result in their low recyclability hindering the full exploitation of a truly circular approach for cured thermosets. In this experimental work, the recyclability of a bio-based fully recyclable epoxy resin using a mild chemical recycling process was demonstrated. The recycled polymer obtained was fully characterized to ascertain its structure and properties. MALDI (Matrix-Assisted Laser Desorption/Ionization), GPC (Gel Permeation Chromatography) and NMR (Nuclear Magnetic Resonance) spectroscopy to determine the chemical structure of the recycled polymer were used. The thermomechanical properties of the cured virgin network and of the recycled product obtained were measured by DSC (Differential Scanning Calorimetry) and DMA (Dynamic Mechanical Analysis). Thermogravimetric analysis of the recycled polymer was also performed. The recycled polymer was transformed into a polyurethane by reacting ...

Research paper thumbnail of Molecular Weight Determination and Structural Analysis in Polydisperse Polymers by Hyphenated Gel Permeation Chromatography/Matrix-Assisted Laser Desorption Ionization—Time of Flight Mass Spectrometry

International Journal of Polymer Analysis and Characterization, Mar 1, 1997

Research paper thumbnail of Synthesis and characterization of poly(ether ketone)/poly(ether sulfone) alternating and sequential copolymers by electrophilic reactions

Macromolecular Chemistry and Physics, Mar 1, 1996

Bis(b-naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of b-naphthol with 2,6-difluorob... more Bis(b-naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of b-naphthol with 2,6-difluorobenzonitrile in N-methyl-2-pyrrolidone (NMP) in the presence of KOH and K 2 CO 3. Poly(ether ketone ether ketone ketone)(PEKEKK) /poly(ether ether ketone ketone) (PEEKK) copolymers containing naphthalene and pendant cyano groups were obtained by electrophilic Friedel-Crafts polycondensation of terephthaloyl chloride (TPC) with varying mole proportions of 4,4 0-diphenoxybenzophenone (DPOBP) and 2,6-bis(b-naphthoxy)benzonitrile (BNOBN) using 1,2dichloroethane (DCE) as solvent and NMP as Lewis base in the presence of anhydrous AlCl 3. The resulting polymers were characterized by various analytical techniques, such as FTIR, DSC, TG, and WAXD. The results indicated that the crystallinity and melting temperature of the polymers decreased with increase in concentration of the BNOBN units in the polymer, the glass transition temperature of the polymers increased with increase in concentration of the BNOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 536 C in N 2 atmosphere. The copolymers have good resistance to acidity, alkali, and organic solvents. Because of the melting temperature (T m) depression with increase in the BNOBN content in the reaction system, the processability of the resultant coplymers could be effectively improved. V

Research paper thumbnail of Application of size exclusion chromatography matrix-assisted laser desorption/ionization time-of-flight to the determination of molecular masses in polydisperse polymers

Rapid Communications in Mass Spectrometry, May 15, 1998

ABSTRACT The determination of molecular mass (MM) data for polydisperse polymers by size exclusio... more ABSTRACT The determination of molecular mass (MM) data for polydisperse polymers by size exclusion chromatography matrix assisted laser desorption/ionization time-of-flight (SEC/MALDI-TOF) involves the fractionation of samples through an analytical SEC. Selected fractions are then analysed by MALDI-TOF and the mass spectra of these nearly monodisperse samples allow the determination of Mn and Mw averages. To test the reliability of the molecular mass estimates by the SEC/MALDI-TOF method, a sample of polymethylmethacrylate (PMMA), two samples of polydimethylsiloxane (PDMS), and four samples of copolyesters, all polydisperse, were analysed. The results show that the molecular mass values of PMMA fractions obtained by MALDI-TOF are coincident with those obtained using the SEC calibration plots obtained with anionic PMMA standards. In the case of the two polydimethylsiloxanes (PDMS1 and PDMS2: linear and cyclic, respectively), two slightly differing SEC calibration plots were obtained, reflecting the different structures of the polymer chains of the two samples. The SEC traces of four copolyesters were obtained in tetrahydrofuran and CHCl3. Data on MM, MM distribution solvent effects and copolymer composition are reported. © 1998 John Wiley & Sons, Ltd.

Research paper thumbnail of Synthesis and Characterization of Linear Hyperbranched PBA Block Copolymers, as Potential Polymeric Plasticizers

V INTERNATIONAL CONFERENCE ON TIMES OF POLYMERS (TOP) AND COMPOSITES, 2010

Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a on... more Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a one-pot synthesis procedure and well characterized by MALDI-TOF mass spectrometry, H-NMR and SEC tools, to obtain reliable information on its chemical composition and molar mass distribution.

Research paper thumbnail of An innovative approach for the chemical structural characterization of poly(styrene 4-vinylpyridine) copolymers by matrix-assisted laser desorption/ionization time of flight mass spectrometry

Journal of Applied Polymer Science, Aug 29, 2018

ABSTACT: Poly(styrene-co-4-vinylpyridine) random copolymers with different molar composition were... more ABSTACT: Poly(styrene-co-4-vinylpyridine) random copolymers with different molar composition were synthesized by nitroxidemediated controlled-radical polymerization using 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) as a mediator. We record the matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) spectra under various conditions, and we find (at last) that they show mostly intact ions [using 2(-4-hydroxyphenylazo-)benzoic acid as MALDI matrix]. Spectra are highly resolved, and thus they allow for the determination of all end-groups, even some less-abundant ones. Spectra are dominated by intact "dormant" copolymer chains terminated with TIPNO at one end and with (4-Bromo-phenyl)ethyl group (starting fragment) at the other one. Applying the mass analysis of copolymers (MACO) statistical model to the spectra, we show that the MACO/MALDI-TOF mass spectrometry (MS) analysis can be successfully applied to copolymers having a difference between the mass of the comonomers as small as 1 g mol −1 (the styrene and 4-vinylpyridine units are 104.15 and 105.15 g/mol, respectively), which results in overlapping isotopic patterns. The results are accurate: chemical composition evaluated by means of MS agrees with that calculated by 1 H-nuclear magnetic resonance, for all copolymers investigated. This analytical method allows to extract detailed information on the composition of the copolymer samples and their structure. Glass transition temperatures of copolymers were also determined by differential scanning calorimetry.

Research paper thumbnail of Molecularly imprinted polymer for selective adsorption of diclofenac from contaminated water

Chemical Engineering Journal, Jul 1, 2019

Abstract The presence of pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) ... more Abstract The presence of pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) in the aquatic environment represents a worldwide threat. NSAIDs are considered “emerging contaminants” of water since the traditional methods are not designed to efficiently remove them. Aiming to overcome the limits of the conventional wastewater treatment plants, we propose molecularly imprinted polymers (MIPs) as valid tools for selective adsorption and removal of these drugs from water. In particular, in this work, we have prepared diclofenac-selective MIP by a simple bulk polymerization process. After the characterization of the synthetized polymers, the binding abilities were evaluated in detail through the adsorption of diclofenac in aqueous solution and compared with the abilities of a corresponding non-imprinted polymer used as a reference. Thanks to the imprinting effect, the prepared MIP adsorbs with extreme selectivity its template molecule, i.e. the diclofenac. This effect was evaluated by testing the adsorption abilities towards different drugs, such as acetylsalicylic acid and trimethoprim. In addition, MIP reusability was demonstrated after a simple regeneration step. The strength of this work is due to the low cost synthesis of MIP and to its optimal performance of molecular recognition in water, differentially from many of the traditional MIPs, usually used with organic solvent. Such peculiarities make the material potentially applicable for water treatment on a large scale.

Research paper thumbnail of Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 1. End group and molar mass determination

Rapid Communications in Mass Spectrometry, Nov 30, 1999

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fra... more The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses. The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2. The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones. In agreement with theory, the ratio (M(cycle)/M(linear))(Ve) at a fixed elution volume was found to be 1.22, independent of the molar mass values. Copyright 1999 John Wiley & Sons, Ltd.

Research paper thumbnail of Separation and characterization of cyclic sulfides formed in the polycondensation of dibromoalkanes with aliphatic dithiols

Macromolecules, Nov 1, 1986

MS and GPC analyses are used to identify the cyclic oligomers formed in the polycondensation reac... more MS and GPC analyses are used to identify the cyclic oligomers formed in the polycondensation reactions of aromatic dithiols and dibromoalkanes leading to ar'omatic-aliphatic polysulfides. A correlation exists between the two sets of data obtained by these techniques. Mass spectra of the cyclic oligomers formed in the polymerization reactions are reported.

Research paper thumbnail of Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 2. Self-association due to phenol end groups

Rapid Communications in Mass Spectrometry, Nov 30, 1999

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fra... more The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses. The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2. The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones. In agreement with theory, the ratio (M(cycle)/M(linear))(Ve) at a fixed elution volume was found to be 1.22, independent of the molar mass values. Copyright 1999 John Wiley & Sons, Ltd.

Research paper thumbnail of Mechanism of thermal degradation of polyurethanes. Effect of ammonium polyphosphate

Macromolecules, Aug 1, 1984

The various pathways of degradation of polyurethane based on MDI and propoxylated trimethylol pro... more The various pathways of degradation of polyurethane based on MDI and propoxylated trimethylol propane were studied from the analysis of degradation gases sampled at various temperatures during the heating rise. From the beginning of degradation (25OOC) to 40O0C, we suggest that the main mechanism is the fracture of the polyurethane molecule into primary amine, carbon dioxide, and propenyl ether, the last leading to propene. Beyond this temperature, the mechanism may be reduced to a depolymerization process followed by radical breakdown of the polyol chain and by stripping and rearrangement of simple radicals, all of these giving the gaseous species obtained.

Research paper thumbnail of Molecular and Structural Characterization of Polydisperse Polymers and Copolymers by Combining MALDI-TOF Mass Spectrometry with GPC Fractionation

Macromolecules, Nov 1, 1995

Octafunctionalized spherosilsesquioxanes (Q 8 M 8 H), decorated with Si−H functions, could be use... more Octafunctionalized spherosilsesquioxanes (Q 8 M 8 H), decorated with Si−H functions, could be used to design, by coupling via hydrosilylation with α-methoxy-ω-undecenyl poly(ethylene oxide)s (PEOs), organic− inorganic nanocomposite structures. 1 H, 13 C, and 29 Si NMR; size exclusion chromatography; and Fourier transfrom infrared spectroscopy were used to follow the grafting reaction and determine the molar mass and the functionality of the different species. Hybrid star-shaped poly(ethylene oxide)s of precise molar mass and functionality could be isolated by fractional precipitation of the raw reaction product. Absolute molar masses of the purified star-shaped PEOs, calculated with the assumption of a functionality of 8, were comparable when measured by light scattering in methanol and by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Small-angle X-ray scattering was employed to determine their molecular and structural characteristics, representing the versatility and innovative aspect to this study. Both differential scanning calorimetry and optical microscopy were utilized to elaborate and analyze the thermal properties and crystallization, respectively, of the hybrid stars. Further ongoing work is being carried out currently to investigate and foresee the use of longer PEO branches onto the core.

Research paper thumbnail of Polyetherimide

John Wiley & Sons, Inc. eBooks, Nov 30, 2011

ABSTRACT

Research paper thumbnail of Exchange Reaction Mechanisms in the Reactive Extrusion of Condensation Polymers

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Oct 6, 2017

Research paper thumbnail of Surface evolution of polycarbonate/polyethylene terephthalate blends induced by thermal treatments

Applied Surface Science, 2003

Bisphenol-A polycarbonate (PC) and polyethyleneterephthalate (PET) blends are known to undergo, u... more Bisphenol-A polycarbonate (PC) and polyethyleneterephthalate (PET) blends are known to undergo, upon thermal treatment (melt mixing), exchange reactions leading to the formation of copolymers having a ®nal structure that is also affected by consecutive reactions involving CO 2 and ethylene carbonate losses. In this work we followed the evolution of the surface composition of this system during the melt mixing at 270 8C, both with and without catalysts, by means of time-of-¯ight secondary ion mass spectroscopy (ToF-SIMS). The static SIMS spectra obtained at different treatment times show the appearance of peaks related to newly formed structures and also the modi®cation of the relative intensities of peaks characteristic of both the initial constituents of the blend. From the variation of the relative intensities of peaks related to the bisphenol-A unit of PC and to the phthalate structure of PET, it is shown that after the ®rst stages of melt mixing the surface is PC enriched and that with the progressive formation of a random copolymer the phthalate units increase their concentration at the surface of the system. Hence, as ®nal result of the melt mixing process, the surface composition tends to re¯ect the relative amount of the repeating units in the bulk.

Research paper thumbnail of Polymer Blends Based on 1-Hexadecyl-3-methyl Imidazolium 1,3-Dimethyl 5-Sulfoisophthalate Ionic Liquid: Thermo-Mechanical, Surface Morphology and Antibacterial Properties

Polymers, Feb 16, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Bioaccumulation of trace elements in the sandhopper Talitrus saltator (Montagu) from the Ionian sandy coasts of Sicily

Ecotoxicology and Environmental Safety, Jul 1, 2016

The Ionian beaches of Sicily are of particular ecological interest because they include the basin... more The Ionian beaches of Sicily are of particular ecological interest because they include the basin of the largest active volcano in Europe and hosts both sites subject to natural protection constraints, as well as important industrial settlements. Consequently, the possibilities for these areas to become polluted are numerous. The sandhopper Talitrus saltator has proven to be a good bioindicator of contamination by numerous trace metals on some European coasts. Nevertheless, no data are available for the populations inhabiting the shores of the southern Mediterranean. Now, as metal accumulation has been shown to vary intraspecifically, the aim of this study was to evaluate trace metal accumulation in adults of T. saltator inhabiting Ionian coastal areas of Sicily and make an assessment of natural and anthropogenic metal pollution of this strip of coast. We also extended our survey to As, Co, Mo, Se, Sn and V never investigated before in this species. Significant differences in metal concentration among sites were found in both sand samples and amphipod tissues. The highest metal content was observed near the mouth of Simeto, the longest river of Sicily which collects waters coming from the volcanic territory of Mount Etna. The bioaccumulation of Cd, Cu, Hg and Zn in T. saltator is fully confirmed; it is also proven for As and Mo and assumed for Cr, Fe, Mn and V. Our outcomes let us to evaluate the prevailing influence of telluric contamination of the Ionian sandy shores of Sicily by trace metals. We also come to the conclusion that in the northern sites, pollution originates from volcanic emission while anthropogenic influence prevails in the southern ones.

Research paper thumbnail of The ground beetle Parallelomorphus laevigatus is a potential indicator of trace metal contamination on the eastern coast of Sicily

Ecotoxicology and Environmental Safety, 2017

Carabids are generally considered to be non-specialized predators, and they have been considered ... more Carabids are generally considered to be non-specialized predators, and they have been considered useful ecological indicators. They can play a key role in clarifying the route of contaminants in food webs because they are predators of small invertebrates and, in turn, part of the diet of several vertebrates. The Mediterranean species Parallelomorphus laevigatus, which so far has not been studied from an ecotoxicological point of view, is an excellent ecological indicator in sandy coastal environments. We investigated the accumulation of trace elements in Ionian populations of P. laevigatus and evaluated the transfer of metal through the food chain of the coastal ecosystem. We analyzed 15 metals, including 11 essential metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V and Zn) and four toxic metals (As, Cd, Hg and Pb). Significant differences were found in metal concentration in animal tissues among sites. Our results support the existence of defense mechanisms for the studied species. High values of As, Cd, Cr, Pb, Ni, and Hg detected in the beetles from the control site can be explained by both the emission sources from the nearby industrial plants and the intense agricultural activity. The present paper shows increasing Hg concentrations in the simplified trophic web of sandy beaches and confirms the capability of this pollutant to biomagnify. Moreover, the high value of biomagnification factor (BMF) points to the severe pollution level in this protected area.

Research paper thumbnail of Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with size-exclusion chromatographic fractionation for structural characterization of synthetic aliphatic copolyesters

Rapid Communications in Mass Spectrometry, Feb 7, 2006

We report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF... more We report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and off‐line coupling of size‐exclusion chromatography with MALDI‐TOFMS analysis (SEC/MALDI‐TOFMS) methods for the detailed characterization of poly[(R,S)‐3‐hydroxybutyrate‐co‐L‐lactic acid], P[(R,S)‐3HB‐co‐LA], and poly[(R,S)‐3‐hydroxybutyrate‐co‐ε‐caprolactone], P[(R,S)‐3HB‐co‐CL], copolymer samples which are expected to be used in special medical application as scaffolds for cartilage and soft tissue engineering. The novel copolyesters contained randomly distributed (R,S)‐3‐hydroxybutyrate structural units, were synthesized by transesterification of the corresponding homopolymers, i.e. atactic poly[(R,S)‐3‐hydroxybutyrate], a‐PHB, and poly(L‐Lactide) (PLLA) or poly(ε‐caprolactone) (PCL), respectively. The MS methods used for the characterization of the resulting polydisperse copolyester samples were supported by classical methods (NMR, SEC). The structures of individual copolyester macromolecules, including end‐group chemical structures, were established using initially MALDI‐TOFMS and then SEC/MALDI‐TOFMS. The compositions of the copolyesters were determined by two methods, namely based on 1H NMR and MALDI‐TOF spectra. The two sets of values showed good agreement. The sequence distribution was determined using the signal intensities of individual copolyester macromolecules, which appeared in MALDI‐TOF mass spectra. Furthermore, sequence analysis gave information about the degree of transesterification. The copolyesters synthesized, with only one exception, were demonstrated to be almost random, which implies that the ester‐ester exchange was close to completion. Copyright © 2006 John Wiley & Sons, Ltd.

Research paper thumbnail of Packaging effects on highly nutritional value beverage obtained by a mix of typical sicilian fruits in accelerated storage

Food Packaging and Shelf Life

Research paper thumbnail of Full Recycling and Re-Use of Bio-Based Epoxy Thermosets: Chemical and Thermomechanical Characterization of the Recycled Matrices

Polymers

High performances of thermosets deriving from their covalent intermolecular cross-link bonds resu... more High performances of thermosets deriving from their covalent intermolecular cross-link bonds result in their low recyclability hindering the full exploitation of a truly circular approach for cured thermosets. In this experimental work, the recyclability of a bio-based fully recyclable epoxy resin using a mild chemical recycling process was demonstrated. The recycled polymer obtained was fully characterized to ascertain its structure and properties. MALDI (Matrix-Assisted Laser Desorption/Ionization), GPC (Gel Permeation Chromatography) and NMR (Nuclear Magnetic Resonance) spectroscopy to determine the chemical structure of the recycled polymer were used. The thermomechanical properties of the cured virgin network and of the recycled product obtained were measured by DSC (Differential Scanning Calorimetry) and DMA (Dynamic Mechanical Analysis). Thermogravimetric analysis of the recycled polymer was also performed. The recycled polymer was transformed into a polyurethane by reacting ...