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  • 11
    Digitale Medien
    Digitale Medien
    Photochemical behavior of poly(organophosphazenes). X. Photo-cross-linking phenomena in poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene] (1992)
    Springer
    Journal of inorganic and organometallic polymers and materials 2 (1992), S. 329-344 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene] ; photochemical behavior ; solution ; solid state ; photo-cross-linking
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The synthesis and photochemical behavior both in solution and in the solid state of poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene] is described. The main reaction of this material under illumination with light of a wavelength longer than 340 nm is the intramolecular abstraction of an hydrogen atom by the excited benzophenone substituent from the 4-isopropylphenoxy moiety geminally substituted on the same phosphorus of the phosphazene chain. In this way highly reactive radical species are produced which induce very efficient photo-cross-linking of the phosphazene copolymer and insolubilization. The efficiency of this process in the solid state is examined in view of the potential application of this material as a polyphosphazene-based negative photoresist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00777250
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  • 12
    Digitale Medien
    Digitale Medien
    Photochemistry and photophysics of poly(organophosphazenes) and related compounds: A review. II. Bimolecular reactions (1994)
    Springer
    Journal of inorganic and organometallic polymers and materials 4 (1994), S. 95-142 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes) ; bimolecular reactions ; photochemistry ; photophysics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In the second part of this review we highlight the bimolecular reactions (hydrogen abstraction, and energy or electron transfer) that take place in the photochemistry of poly(organophosphazenes). Both inter-molecular interactions (i.e. between excited free chromophores and ground state groups attached to the phosphazenes, or between excited phosphazene substituents and external quenchers) and intra-molecular processes (i.e. between excited and ground state groups geminally attached to the same phosphorus or supported to different phosphorus along the polyphosphazene skeleton) are exploited. Suggestions are given on the possible practical application of these reactions in different photochemical domains, e.g. heterogeneous-phase photosensitization, photocrosslinking, photoconductivity, microelectronics, light-induced radical polymerization of vinyl monomers, etc.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01036538
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  • 13
    Digitale Medien
    Digitale Medien
    Photochemical Behavior of Poly(Organophosphazenes). 15. Light-Induced Cross-Linking of [(4-Benzoylphenoxy) x (Methoxyethoxyethoxy)2 − x ] Phosphazene Copolymers (1998)
    Springer
    Journal of inorganic and organometallic polymers and materials 8 (1998), S. 67-88 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes) ; photochemical behavior ; light-induced cross-linking ; poly[bis(methoxyethoxyethoxy)phoshazene] ; benezophenone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The synthesis of a new, highly photosensitive, phosphazene copolymer containing an almost-equimolecular quantity of benzophenone and methoxyethoxyethoxy substituents is reported in this paper, together with the photochemical behavior of this material when irradiated in film both in oxygen and in an argon atmosphere. It has been detected that the photoreactivity of the phosphazene material strongly depends on the light absorption process by the benzophenone moieties, whose selective excitation predominantly brings about an intramolecular hydrogen abstraction reaction from the ethylene oxide units, thus producing highly reactive phosphazene macroradicals. The coupling reactions of these species results in the complete cross-linking of the polyphosphazene substrate and in its total insolubilization. Moreover, the influence of molecular oxygen on the overall photochemical process of the benzophenone/ethyleneoxide-substituted phosphazene copolymer is investigated. The implications of the light-induced reticulation process in the controlled insolubilization of poly[ bis (methoxyethoxyethoxy)phosphazene] are also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022411205861
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  • 14
    Digitale Medien
    Digitale Medien
    Thermosetting Resins and Azo Dyes Based on Phosphazenes (1999)
    Springer
    Journal of inorganic and organometallic polymers and materials 9 (1999), S. 133-150 
    Details
    ISSN: 1572-8870
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this paper we report the preparation of new, phosphazene-based, phenol/formaldehyde thermosetting resins and azo dyes as obtained by carrying out electrophilic substitution reactions of formaldehyde and diazotized aromatic amines, respectively, on free hydroxylic group-containing aryloxy phosphazenes. The synthesis of these last substrates by reacting methoxylated phenoxy and naphthoxy-substituted cyclo and polyphosphazenes with BBr3 under hydrolytic conditions is also described. The reported products were characterized by IR, UV, 1H and 31P {1H} NMR spectroscopy, and by thermogravimetric analysis. Their possible applications as polymeric matrices for the preparation of fiber-reinforced composite materials or as photographic dyes is also envisaged.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1021654910340
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  • 15
    Digitale Medien
    Digitale Medien
    Phosphazene-bound Rose Bengal: A novel photosensitizer for singlet oxygen generation (1991)
    Springer
    Journal of inorganic and organometallic polymers and materials 1 (1991), S. 389-395 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes) ; cyclophosphazenes ; Rose Bengal ; photosensitization ; singlet oxygen ; oxidation ; heterogeneous phase photosensitizer ; 1,3-diphenyl-isobenzofuran
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this paper we report the synthesis and the characterization of cyclo- and polyphosphazenes supporting Rose Bengal. These substrates are suitable for the photosensitized generation of singlet oxygen, both in homogeneous and in heterogeneous phase. The efficiency of1O2 production has been measured in homogeneous solution using, as photosensitizer, the cyclophosphazene-bound Rose Bengal and considering, as testing reaction, the oxidation of 1,3-diphenylisobenzofuran; it was found comparable to that of free Rose Bengal in the same experimental conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00702501
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  • 16
    Digitale Medien
    Digitale Medien
    XPS and DSC Studies of Solution Cast Polystyrene/Poly(organophosphazene) Blends. II. Polystyrene/Poly(4-phenoxyphenoxy)phosphazene (2000)
    Springer
    Journal of inorganic and organometallic polymers and materials 10 (2000), S. 61-72 
    Details
    ISSN: 1572-8870
    Schlagwort(e): polyphosphazene ; polystyrene ; blends ; XPS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Blends of polystyrene (PS) with poly(4-phenoxyphenoxy)phosphazene (PPA) were studied by differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). A third component, poly(2,6-dimethyl-1,4-phenylene ether) (PPE), was added to improve the compatibility. While DSC and XPS reveal that PS and PPA are incompatible, the presence of PPE increases the compatibility between the two polymers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009408624132
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  • 17
    Digitale Medien
    Digitale Medien
    XPS and DSC Studies of Solution Cast Polystyrene/Poly(organophosphazene) Blends. I. Polystyrene/Poly(phenoxy)phosphazene (2000)
    Springer
    Journal of inorganic and organometallic polymers and materials 10 (2000), S. 23-38 
    Details
    ISSN: 1572-8870
    Schlagwort(e): polyphosphazene ; polystyrene ; blends ; X-ray photoelectron spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Blends of polystyrene (PS) with poly(phenoxy)phosphazene (PPN) were studied by differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). A third component, poly(2,6-dimethyl-1,4-phenylene ether) (PPE), was added with the aim of increasing compatibility of the blends. T g values did not vary in the PS/PPN blends, indicating that the components are substantially incompatible. The addition of PPE did not change the situation much even though some compatibility between PPN and PPE was detected. XPS on the cast films showed that only PPN was present at the surface. The surface composition of the blends was found to be dependent on the preparation technique.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009452331855
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  • 18
    Digitale Medien
    Digitale Medien
    Photochemistry and photophysics of poly(organophosphazenes) and related compounds: A review. I. Monomolecular processes (1994)
    Springer
    Journal of inorganic and organometallic polymers and materials 4 (1994), S. 1-29 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes) ; monomolecular processes ; photochemistry ; photophysics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this review we report an outline of the synthesis, UV-Vis spectral characterization, and light-induced reactivity in monomolecular processes of poly(organophosphazenes). The photoreactivity of phosphazene polymers, both in solution and in solid state, strongly depends on the nature of the chromophore attached to the phosphorus atoms of the inorganic −P=N − backbone. In fact, polyphosphazenes not bearing mobile hydrogen atoms in the side moieties undergo, in the first excited singlet state, homolytic eleavage of the bonds connecting the substituents to the inorganic backbone: free radicals of the substituents and phosphazene macroradicals are formed. Moreover, for polyphosphazenes containing labile hydrogens in the side groups, C–H bond scission takes place with the formation of free hydrogens and radicals located in the phosphazene substituents. From these species degradation or crosslinking of the macromolecules will follow according to the experimental conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00684025
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  • 19
    Digitale Medien
    Digitale Medien
    Photochemistry and photophysics of poly(organophosphazenes) and related compounds: A review. III. Applicative aspects (1994)
    Springer
    Journal of inorganic and organometallic polymers and materials 4 (1994), S. 205-236 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes) ; photochemistry ; photophysics ; photochromism ; azobenzene ; spiropyran ; light-induced grafting ; photo-stabilizers ; photoinitiators
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In the third part of this review we report some applicative aspects of poly(organophosphazenes) in photochemical fields. In particular, the possible application of phosphazene polymers that contain azobenzene or spiropyran residues as photochromic macromolecules is outlined; the light-induced grafting of organic, carbon-backboned polymers onto polyphosphazene matrices, as a method of modifying both surface and bulk properties of these materials, is highlighted; and the potential application of cyclophosphazenes as photo-stabilizers for commercial organic polymers or as photoinitiators for radical polymerization of vinyl monomers is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00683716
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  • 20
    Digitale Medien
    Digitale Medien
    Grafting reactions onto poly(organophosphazenes). VIII. Grafting kinetics, surface properties, thermal and dynamic mechanical characterization of phosphazene grafted copolymers containing poly(vinyl acetate) and poly(vinyl alcohol) (1996)
    Springer
    Journal of inorganic and organometallic polymers and materials 6 (1996), S. 195-220 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Poly(organophosphazenes): grafting kinetics ; polyvinylacetate ; polyvinylalcohol ; surface analysis ; thermomechanical characterization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this paper we report the light-induced grafting kinetics of vinyl acetate onto three poly(organophosphazene) films, i.e., poly[bis(4-methylphenoxy) phosphazene], poly[bis(4-ethylphenoxy)phosphazene], and poly[bis(4-secbutylphenoxy)phosphazene], and the characterization of the poly(organophosphazene)-g-poly-vinylacetate materials and the poly(organophosphazene)-g-poly-vinylalcohol copolymers, derived from hydrolysis of the previous ones. The reactivity of poly(organophosphazenes) was found to be directly dependent on the different crystallinity content. The modification of the surface properties was studied by SEM analysis and DCA measurements. The higher the grafting pereentage, the higher the roughness of surface and the lower the receeding contact angle. DSC analysis revealed that the crystallizability of poly(organophosphazene)-g-poly-vinylacetate decreases as the grafting percentage increases. Finally, DMTA measurements confirmed the presence of polyvinylacetate after grafting and its disappearance and the simultaneous increase in thermomechanical stability after hydrolysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01057747
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