The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform
Jeanluc Gardette - One of the best experts on this subject based on the ideXlab platform.
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influence of water on the photooxidation of khj Phenoxy Resins 1 mechanisms
Polymer Degradation and Stability, 2011Co-Authors: Yassine Malajati, Sandrine Therias, Jeanluc GardetteAbstract:Abstract This study is devoted to the influence of water on the mechanisms of photooxidation of anticorrosion coatings based on epoxy Resins used in extremely aggressive media like the marine environment. The two principal environmental parameters to be considered are sunlight (UV-light) and water. It is important to understand the role of these two environmental parameters on the ageing of epoxy anticorrosion coatings. On the basis of the effect of photooxidation on the molecular structure under “dry” conditions, water was introduced into the ageing process with either alternating cycles of irradiation/immersion in water or simultaneously by irradiation of the polymer in water. The presence of water had two effects on the photodegradation of PKHJ ® Phenoxy resin; the first one was on the degradation of the main photoproduct (phenyl formates) formed during irradiation through a hydrolysis reaction leading to the release of formic acid. The second effect consisted of an increase in the photooxidation rate by the formation of photo-initiators.
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photo oxidation of Phenoxy Resins at long and short wavelengths i identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—I. Identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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photo oxidation of Phenoxy Resins at long and short wavelengths ii mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—II. Mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
Agnes Rivaton - One of the best experts on this subject based on the ideXlab platform.
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photo oxidation of Phenoxy Resins at long and short wavelengths i identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—I. Identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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photo oxidation of Phenoxy Resins at long and short wavelengths ii mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—II. Mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
Laurent Moreau - One of the best experts on this subject based on the ideXlab platform.
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photo oxidation of Phenoxy Resins at long and short wavelengths i identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—I. Identification of the photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Phenoxy resin films were exposed to radiation of long wavelengths (λ > 300 nm) and short wavelength (λ = 254 nm). The products resulting from the photo-oxidation of Phenoxy resin have been identified by means of various techniques such as Fourier transform infra-red spectroscopy and ultraviolet spectrophotometry, chemical derivatization reactions and physical treatments, and mass spectrometry. Results show that phenyl formate end-groups are the main oxidation products that accumulate in films photo-oxidized at long wavelengths; no phenyl formate structures have been found under short-wavelength exposure.
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photo oxidation of Phenoxy Resins at long and short wavelengths ii mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
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Photo-oxidation of Phenoxy Resins at long and short wavelengths—II. Mechanisms of formation of photoproducts
Polymer Degradation and Stability, 1997Co-Authors: Agnes Rivaton, Laurent Moreau, Jeanluc GardetteAbstract:Abstract Products resulting from the photo-oxidation of Phenoxy resin were identified and reported in the preceding paper; mechanisms that account for formation of the photoproducts are proposed in the present paper. Results show that the dominant photo-oxidative pathway is a photo-induced oxidation implying hydroperoxidation. In the first steps of the oxidation induced by long wavelengths (λ > 300 nm), the main reactions involve the methylene groups in the α position to the ether groups. Photo-unstable hydroperoxides are transformed into phenyl formate end-groups. By contrast, no phenyl formate end-groups have been found under short-wavelength exposure (λ = 254 nm); it is believed that hydrogen abstraction of hydroperoxides formed in α positions to ether is more likely to occur than the anticipated homolysis.
Yassine Malajati - One of the best experts on this subject based on the ideXlab platform.
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influence of water on the photooxidation of khj Phenoxy Resins 1 mechanisms
Polymer Degradation and Stability, 2011Co-Authors: Yassine Malajati, Sandrine Therias, Jeanluc GardetteAbstract:Abstract This study is devoted to the influence of water on the mechanisms of photooxidation of anticorrosion coatings based on epoxy Resins used in extremely aggressive media like the marine environment. The two principal environmental parameters to be considered are sunlight (UV-light) and water. It is important to understand the role of these two environmental parameters on the ageing of epoxy anticorrosion coatings. On the basis of the effect of photooxidation on the molecular structure under “dry” conditions, water was introduced into the ageing process with either alternating cycles of irradiation/immersion in water or simultaneously by irradiation of the polymer in water. The presence of water had two effects on the photodegradation of PKHJ ® Phenoxy resin; the first one was on the degradation of the main photoproduct (phenyl formates) formed during irradiation through a hydrolysis reaction leading to the release of formic acid. The second effect consisted of an increase in the photooxidation rate by the formation of photo-initiators.
Sandrine Therias - One of the best experts on this subject based on the ideXlab platform.
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influence of water on the photooxidation of khj Phenoxy Resins 1 mechanisms
Polymer Degradation and Stability, 2011Co-Authors: Yassine Malajati, Sandrine Therias, Jeanluc GardetteAbstract:Abstract This study is devoted to the influence of water on the mechanisms of photooxidation of anticorrosion coatings based on epoxy Resins used in extremely aggressive media like the marine environment. The two principal environmental parameters to be considered are sunlight (UV-light) and water. It is important to understand the role of these two environmental parameters on the ageing of epoxy anticorrosion coatings. On the basis of the effect of photooxidation on the molecular structure under “dry” conditions, water was introduced into the ageing process with either alternating cycles of irradiation/immersion in water or simultaneously by irradiation of the polymer in water. The presence of water had two effects on the photodegradation of PKHJ ® Phenoxy resin; the first one was on the degradation of the main photoproduct (phenyl formates) formed during irradiation through a hydrolysis reaction leading to the release of formic acid. The second effect consisted of an increase in the photooxidation rate by the formation of photo-initiators.