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Papers by maurizio veronelli
Environmental Advances, 2021
Due to the Covid-19 pandemic, the use of disposable face masks has been adopted worldwide as a pr... more Due to the Covid-19 pandemic, the use of disposable face masks has been adopted worldwide as a precautionary measure to slow down the transmission of the virus. This has determined an unprecedented rise in the production of these protective equipments, and unfortunately to a new form of environmental contamination due to the improper disposal. To provide a preliminary estimation of the release of microfibers by a surgical mask dumped in the marine environment, we carried out artificial weathering experiments. Results indicated that a single surgical mask submitted to 180 hours UV-light irradiation and vigorous stirring in artificial seawater may release up to 173,000 fibers/ day. Moreover, SEM and micro-FTIR analysis carried out onto surgical masks collected from Italian beaches highlighted the same morphological and chemical degradation signature observed in the masks subjected to the artificially weathering experiments, confirming the risks of a similar microfiber release into the marine environment.
Acta Polymerica
Chain‐length‐dependent π electron delocalization is analyzed in pristine oligofurans and polyfura... more Chain‐length‐dependent π electron delocalization is analyzed in pristine oligofurans and polyfuran by means of Fourier transform Raman spectroscopy. Neutral polyfuran shows a large frequency dispersion with conjugation length and it has not yet reached saturation at the level of the hexamer. In spite of such a large π electron delocalization the polymer seems to show an unexpectedly good stability in air at room temperature. Regio‐defined poly(2,5‐difurans) could be good candidates for technological developments.
Acta Polymerica
The photoinduced infrared spectra of stretch-oriented polyhexylthiophene and polyoctylthiophene a... more The photoinduced infrared spectra of stretch-oriented polyhexylthiophene and polyoctylthiophene are reported as a function of the polarization both of the pump light and of the probe IR beam. There is no change in the intensity of photoinduced IR absorption due to the polarization of the pump; however, the spectra show parallel dichroism when the probe is polarized. The experimental results are analyzed on the basis of the “effective conjugation coordinate” theory (ECC).
Synthetic Metals, 1993
We present absolute FT Raman intensity measurements on polyenic systems of various chain lengths ... more We present absolute FT Raman intensity measurements on polyenic systems of various chain lengths in order to assess the validity of a semiclassical model, recently proposed, which stresses the importance of the nuclear contribution to the non linear optical response of a conjugated molecule in a static field, and relates the nuclear contribution to ~ to the Raman intensities.
Polymer Degradation and Stability, 1999
A series of PVC samples were thermally dehydrochlorinated under nitrogen. The amount of HCl was m... more A series of PVC samples were thermally dehydrochlorinated under nitrogen. The amount of HCl was monitored and nine samples with increasing quantity of liberated HCl were obtained (from 0.03 to 2.0% of elimination of HCl, where 100% indicates the theoretically total removal of HCl from PVC). These samples were characterised with Raman and UV±Vis spectroscopy. Subsequently, the dehydrochlorinated resins were subjected to accelerated weathering with UV-B lamps and the kinetics of formation of the photoproducts were followed with FTIR spectroscopy, in order to study the in¯uence of the presence of conjugated sequences on the photooxidation of PVC. The results show that the presence of conjugated sequences into the thermally degraded PVC samples (Raman spectroscopy indicates the presence of long conjugated sequences already at dehydrochlorination rates lower than 0.01%) does not in¯uence either the mechanism or the kinetics of the photooxidation of the PVC chains. The mechanism of photooxidation is discussed.
Journal of Raman Spectroscopy, 1995
ABSTRACT Micro resonance Raman spectra of a series of synthetic carotenoids and of a large number... more ABSTRACT Micro resonance Raman spectra of a series of synthetic carotenoids and of a large number of bird's feathers which contain various kinds of carotenoids were analysed on the basis of the effective conjugation coordinate (ECC) theory. The data obtained on parrots provide the first structural data on the chemical nature of the pigments embedded in their feathers, and show that these pigments are unmethylated polyene molecules. Data on the molecular orientation of the carotenoids and on the presence of different pigments in the same feather are presented and discussed.
Journal of Elastomers and Plastics, 2000
The Journal of Chemical Physics, 1993
The main feature of β,β’-bridge–α,α’-bithienyls is that their conformation is controlled by the b... more The main feature of β,β’-bridge–α,α’-bithienyls is that their conformation is controlled by the bridge length. This class of molecules could be useful for the understanding of the intra and intermolecular processes which determine the conductivity of the corresponding polymers. In this work we have recorded and studied (i) the electronic spectra of the monomers, (ii) the vibrational spectra (IR, Raman λexc=514 nm, FT–Raman λexc=1064 nm) of the monomers and polymers in the pristine state, (iii) the IR spectra of the doped polymers, and (iv) the IR spectra (probe) of the polymers photoinduced by visible light (pump). The interpretation of the spectra is made in terms of the ‘‘effective conjugation coordinate’’ theory. Poly(cyclopentabithiophene) P(T+1) has the largest π-electron delocalization with a wide distribution of conjugation lengths. In poly(cycloheptabithiophene) P(T+3) π electrons are highly localized, while an intermediate situation is observed in poly(dihydrobenzobithiophene) P(T+2). The various aspects of intra and intermolecular hopping of charge carriers are discussed.
The Journal of Chemical Physics, 1994
ABSTRACT Oligopyrroles with increasing chain length and polypyrroles were recently synthesized wi... more ABSTRACT Oligopyrroles with increasing chain length and polypyrroles were recently synthesized with new chemical methods. In this paper, we analyze their infrared and Raman spectra. The spectra can be nicely interpreted in terms of recent theoretical concepts of vibrational dynamics of polyconjugated systems. The spectra thus become a tool for deriving information on the structure of these materials.
The Journal of Chemical Physics, 1991
Acta Polymerica
Infrared spectrum of photoexcited polyfuran attempts have been reported on the synthesis of polyf... more Infrared spectrum of photoexcited polyfuran attempts have been reported on the synthesis of polyfuran Recently neutral PFu has been prepared by electroreduction of 2,s-dibromofuran by using Ni(bipy)32' as a catalyst
Environmental Advances, 2021
Due to the Covid-19 pandemic, the use of disposable face masks has been adopted worldwide as a pr... more Due to the Covid-19 pandemic, the use of disposable face masks has been adopted worldwide as a precautionary measure to slow down the transmission of the virus. This has determined an unprecedented rise in the production of these protective equipments, and unfortunately to a new form of environmental contamination due to the improper disposal. To provide a preliminary estimation of the release of microfibers by a surgical mask dumped in the marine environment, we carried out artificial weathering experiments. Results indicated that a single surgical mask submitted to 180 hours UV-light irradiation and vigorous stirring in artificial seawater may release up to 173,000 fibers/ day. Moreover, SEM and micro-FTIR analysis carried out onto surgical masks collected from Italian beaches highlighted the same morphological and chemical degradation signature observed in the masks subjected to the artificially weathering experiments, confirming the risks of a similar microfiber release into the marine environment.
Acta Polymerica
Chain‐length‐dependent π electron delocalization is analyzed in pristine oligofurans and polyfura... more Chain‐length‐dependent π electron delocalization is analyzed in pristine oligofurans and polyfuran by means of Fourier transform Raman spectroscopy. Neutral polyfuran shows a large frequency dispersion with conjugation length and it has not yet reached saturation at the level of the hexamer. In spite of such a large π electron delocalization the polymer seems to show an unexpectedly good stability in air at room temperature. Regio‐defined poly(2,5‐difurans) could be good candidates for technological developments.
Acta Polymerica
The photoinduced infrared spectra of stretch-oriented polyhexylthiophene and polyoctylthiophene a... more The photoinduced infrared spectra of stretch-oriented polyhexylthiophene and polyoctylthiophene are reported as a function of the polarization both of the pump light and of the probe IR beam. There is no change in the intensity of photoinduced IR absorption due to the polarization of the pump; however, the spectra show parallel dichroism when the probe is polarized. The experimental results are analyzed on the basis of the “effective conjugation coordinate” theory (ECC).
Synthetic Metals, 1993
We present absolute FT Raman intensity measurements on polyenic systems of various chain lengths ... more We present absolute FT Raman intensity measurements on polyenic systems of various chain lengths in order to assess the validity of a semiclassical model, recently proposed, which stresses the importance of the nuclear contribution to the non linear optical response of a conjugated molecule in a static field, and relates the nuclear contribution to ~ to the Raman intensities.
Polymer Degradation and Stability, 1999
A series of PVC samples were thermally dehydrochlorinated under nitrogen. The amount of HCl was m... more A series of PVC samples were thermally dehydrochlorinated under nitrogen. The amount of HCl was monitored and nine samples with increasing quantity of liberated HCl were obtained (from 0.03 to 2.0% of elimination of HCl, where 100% indicates the theoretically total removal of HCl from PVC). These samples were characterised with Raman and UV±Vis spectroscopy. Subsequently, the dehydrochlorinated resins were subjected to accelerated weathering with UV-B lamps and the kinetics of formation of the photoproducts were followed with FTIR spectroscopy, in order to study the in¯uence of the presence of conjugated sequences on the photooxidation of PVC. The results show that the presence of conjugated sequences into the thermally degraded PVC samples (Raman spectroscopy indicates the presence of long conjugated sequences already at dehydrochlorination rates lower than 0.01%) does not in¯uence either the mechanism or the kinetics of the photooxidation of the PVC chains. The mechanism of photooxidation is discussed.
Journal of Raman Spectroscopy, 1995
ABSTRACT Micro resonance Raman spectra of a series of synthetic carotenoids and of a large number... more ABSTRACT Micro resonance Raman spectra of a series of synthetic carotenoids and of a large number of bird's feathers which contain various kinds of carotenoids were analysed on the basis of the effective conjugation coordinate (ECC) theory. The data obtained on parrots provide the first structural data on the chemical nature of the pigments embedded in their feathers, and show that these pigments are unmethylated polyene molecules. Data on the molecular orientation of the carotenoids and on the presence of different pigments in the same feather are presented and discussed.
Journal of Elastomers and Plastics, 2000
The Journal of Chemical Physics, 1993
The main feature of β,β’-bridge–α,α’-bithienyls is that their conformation is controlled by the b... more The main feature of β,β’-bridge–α,α’-bithienyls is that their conformation is controlled by the bridge length. This class of molecules could be useful for the understanding of the intra and intermolecular processes which determine the conductivity of the corresponding polymers. In this work we have recorded and studied (i) the electronic spectra of the monomers, (ii) the vibrational spectra (IR, Raman λexc=514 nm, FT–Raman λexc=1064 nm) of the monomers and polymers in the pristine state, (iii) the IR spectra of the doped polymers, and (iv) the IR spectra (probe) of the polymers photoinduced by visible light (pump). The interpretation of the spectra is made in terms of the ‘‘effective conjugation coordinate’’ theory. Poly(cyclopentabithiophene) P(T+1) has the largest π-electron delocalization with a wide distribution of conjugation lengths. In poly(cycloheptabithiophene) P(T+3) π electrons are highly localized, while an intermediate situation is observed in poly(dihydrobenzobithiophene) P(T+2). The various aspects of intra and intermolecular hopping of charge carriers are discussed.
The Journal of Chemical Physics, 1994
ABSTRACT Oligopyrroles with increasing chain length and polypyrroles were recently synthesized wi... more ABSTRACT Oligopyrroles with increasing chain length and polypyrroles were recently synthesized with new chemical methods. In this paper, we analyze their infrared and Raman spectra. The spectra can be nicely interpreted in terms of recent theoretical concepts of vibrational dynamics of polyconjugated systems. The spectra thus become a tool for deriving information on the structure of these materials.
The Journal of Chemical Physics, 1991
Acta Polymerica
Infrared spectrum of photoexcited polyfuran attempts have been reported on the synthesis of polyf... more Infrared spectrum of photoexcited polyfuran attempts have been reported on the synthesis of polyfuran Recently neutral PFu has been prepared by electroreduction of 2,s-dibromofuran by using Ni(bipy)32' as a catalyst