Excitation Spectra of Heat-Treated Poly(vinyl Alcohol) Film

Maruyama, Kei; Akahoshi, Hiroshi; Kobayashi, Michio; Tanizaki, Yoshié

doi:10.1246/cl.1983.1863

Cited by 9 publications

(7 citation statements)

References 4 publications

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“…The formation of the conjugated polyene structures in the thermal degradation of PVC and PVA is mainly via dehydrochlorination [21][22][23][24][25][26][27][28][29][30][31][32] and dehydration [33][34][35] , respectively. The effects of the preirradiation on the conjugated structure formation observed in this work are believed to be related to the radiation-induced structure changes on the polymer chains as well as the generated small molecular products.…”

Section: Discussionmentioning

confidence: 99%

Radiation effects on the thermal degradation of poly(vinyl chloride) and poly(vinyl alcohol)

Zhao

Yamamoto

Tagawa

1998

J. Polym. Sci. A Polym. Chem.

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Radiation effects on the formation of conjugated double bonds in the thermal degradation of poly(vinyl chloride) (PVC) and poly(vinyl alcohol) (PVA) were investigated. Thin films of PVC and PVA were either irradiated with γ‐rays at ambient temperature (pre‐irradiation) and then subjected to thermal treatment, or irradiated at elevated temperatures (in situ irradiation). An extensive enhancement of the thermal degradation was observed for the pre‐irradiation of the PVC films, which was more effective than the effect of the in situ irradiation at the same absorption dose. For the PVA degradation, however, the effect of the in situ irradiation was larger than that of the pre‐irradiation. The results were explained and related mechanisms were discussed based on radiation‐induced chemical reactions and their individual contributions to the thermal degradation behaviors of the two polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3089–3095, 1998

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Section: Discussionmentioning

confidence: 99%

Radiation effects on the thermal degradation of poly(vinyl chloride) and poly(vinyl alcohol)

Zhao

Yamamoto

Tagawa

1998

J. Polym. Sci. A Polym. Chem.

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“…While the ultraviolet absorption provides only very indistinct evidence of the chromophores which cause the yellow discoloration-the only prominent mid-ultraviolet peak at 280nm may derive not from the discolored polymer but from a non-ionic surfactant containing a benzene ring-the increase of absorption across a broad wavelength region and the evidence of a series of absorption peaks occurring at regular intervals suggest a similarity to the chromophores which are produced in vinyl polymers such as polyvinyl alcohol (PVOH) [17,18] and polyvinyl chloride (PVC) [19]. In these other polymers, discoloration arises from 'polyene' structures, carbon chains containing conjugated double bonds (alternating single and double carboncarbon bonds in sequence along the chain).…”

Section: Discussionmentioning

confidence: 99%

“…Strong fluorescence of these polyene chromophores has been noted in studies of PVOH [17,18] and, because of the importance of these polyene structures in biological vision systems, the absorption and fluorescence properties of these compounds have been studied in great detail. It has been found that the fluorescence can only occur in moderate-length chromophores with four to eight double bonds (including the terminal carbonyl) having an unusual ordering of lowlying excited states [21][22][23][24][25].…”

Section: Discussionmentioning

confidence: 99%

The natural and accelerated aging of an acrylic artists' medium

Whitmore¹,

Colaluca²

1995

Studies in Conservation

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Changes in appearance and in the chemical and mechanical properties of films of Liquitex acrylic gloss medium, a commercial artists' medium based on an acrylic polymer dispersion, have been studied during natural aging in the dark and in accelerated thermal and light exposure tests. In dark storage at room temperature and humidity, the films acquire a haze and slight yellow discoloration in a few weeks, while the tensile properties stabilize only after film formation has progressed for about 50 days. Crosslinking seems to occur slowly at room temperature, causing the film to become only partially soluble in benzene and butanone, although the extent of this crosslinking does not seem to cause difficulty in film removal even after extended heat aging. The resistance of this polymer material to photochemical degradation by near-ultraviolet light is very high. Exposure of these films to near-ultraviolet light causes very slow scission and oxidation of the polymer, producing a gradual increase in solubility and hardness; severely degraded films suffer a sudden loss of tensile strength.

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“…This dependence often derives from restrictions on the transport of reagents to within short distances from a surface or interface in a material. A classic effect is the yellowing of many polymers [2][3][4][5][6][7][8][9][10][11][12][13] under exposure to UV radiation. This process occurs efficiently in zones of a material in which oxygen concentrations are low or negligible, at depths of tens or hundreds of micrometers below the surface.…”

Section: Introductionmentioning

confidence: 99%

“…In poly(vinyl chloride) (PVC) [2][3][4][5][6][7][8][9] and related polymers such as poly(vinyl alcohol) (PVA) [10][11][12] and poly(vinyl acetate) (PVAc), 13 when thin films are subjected to thermal or UV photo-degradation, yellowing arises from the for-mation of poly(ene) chains of structure -(CHϭCH) n -. As degradation proceeds, the chain length n increases from 2-4 through 12 units or greater, 7,12 producing increased visible wavelength absorption in sub-surface zones.…”

Section: Introductionmentioning

confidence: 99%

Depth Profiling of the Optical Absorption Coefficient in Ultraviolet-Degraded Poly(Vinylchloride) Films by Dual Beam Light Profile Microscopy

Power

Nepotchatykh

2005

Appl Spectrosc

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Dual beam laser light profile microscopy (LPM) was applied in this work to the depth mapping of the optical absorption coefficient in photo-degraded poly(vinyl chloride) films. Depth profiles followed the absorption coefficient of a conjugated polyene photoproduct at visible wavelengths in photolyzed films of approximately 200 mum thickness. Both continuous and layered (separable laminate) films were studied. The absorption coefficient profiles reconstructed from photo-degraded thin films showed the classic concentration profiles seen in the literature for PVC degraded in the presence of oxygen and nitrogen atmospheres. In the case of single thin layers with continuous properties, the depth profiles were smooth and regular with minimum spatial noise. In the LPM of laminate structures, more optical anomalies were present because of the multiply interfacial structures that appeared in both the images and the reconstructed depth profiles. Notwithstanding, it was possible to profile the optical absorption coefficient at a level of error comparable to standard microtome methods. The latter was determined by comparing the LPM results to a destructive layer-by-layer analysis performed in parallel on the imaged materials. The dual beam LPM method should be generally useful for establishing polyene concentration profiles in industrial materials produced by photochemical, thermal, and chemical degradation mechanisms.

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Excitation Spectra of Heat-Treated Poly(vinyl Alcohol) Film

Abstract: Among species of general structure (\( \llap–CH=CH \llap–)\)n produced in the heat-treated PVA substrate, the existence of polyene systems with n=2 to 5 were successfully confirmed by means of the excitation spectra and the Lewis–Calvin’s plot.

Cited by 9 publications

References 4 publications

Radiation effects on the thermal degradation of poly(vinyl chloride) and poly(vinyl alcohol)

Radiation effects on the thermal degradation of poly(vinyl chloride) and poly(vinyl alcohol)

The natural and accelerated aging of an acrylic artists' medium

Depth Profiling of the Optical Absorption Coefficient in Ultraviolet-Degraded Poly(Vinylchloride) Films by Dual Beam Light Profile Microscopy

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