Photoconductance of Organic Polymers

Myl'nikov, V. S.

doi:10.1070/rc1974v043n10abeh001868

Cited by 13 publications

(3 citation statements)

References 9 publications

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“…PVA exhibits a strong hydrophilic and hydrogen bonding characteristic due to its hydroxyl groups, thus it is able to form cross linked hydrogels . Polyvinyl alcohol as a polymer with side groups has also been used to prepare conjugated polymers such as polyacetylene (PA) which are types of polymers with long conjugated double bonds and have spectacular properties and used in the areas of optical, electrical, magnetic and, in recent years, photo‐catalysis fields …”

Section: Introductionmentioning

confidence: 99%

The investigation of thermal decomposition pathway and products of poly(vinyl alcohol) by TG‐FTIR

Taghizadeh

Yeganeh

Rezaei

2015

J of Applied Polymer Sci

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A generalized form of a semiquantitative method has been developed based on the multilinear least-squares regression technique applied on the entire FTIR absorbance spectrum of a gaseous mixture to determine components concentration. Thermal degradation of poly(vinyl alcohol) samples with high, PVA(98), and low degree of hydrolysis, PVA(80), has been investigated by TG-FTIR simultaneous analysis performed in an inert atmosphere. Analysis of gaseous products was carried out using a routine developed in Matlab and this routine returns the product concentration with a reasonable RMS error. The correlation coefficients of the original mixture spectrum with the mixed output were obtained at some specific peak temperatures using irAnalysis software. The first process is the loss of physically adsorbed water which followed by two main processes of thermal degradation. In spite of the similarity of evolved gaseous products, two samples showed some differences in components concentrations identified in the volatile mixture. Acetaldehyde has been identified as the main volatile product in the first thermal degradation step of PVA(98) and PVA(80). The second major degradation product of PVA(80) is acetic acid due to presence of more residual acetate group while 2-butenal have been identified for PVA(98). Water was mainly produced in the first stage of thermal degradation of PVA(98) while it was identified in the first and second stages for PVA(80). This might be attributed to existence of a competition between water and residual acetate group for elimination that postpones the complete elimination of OH group to the second degradation stage.

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Section: Introductionmentioning

confidence: 99%

The investigation of thermal decomposition pathway and products of poly(vinyl alcohol) by TG‐FTIR

Taghizadeh

Yeganeh

Rezaei

2015

J of Applied Polymer Sci

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“…When such photoreactive moieties are inserted in macromolecular systems, materials having the mechanical properties typical of polymers but structurally modifiable by light absorption can be obtained.1,2 These materials are particularly valuable for possible practical applications in high-speed compact memory devices,1 in photoconductors,3 and in solar energy conversion. 3 In addition, the insertion of photochromic moieties in the main or side chain of macromolecules is very attractive for the investigation of their primary and secondary structure, and of the possible conformational changes consequent of lightinduced structural modifications.4 '8 In this context, polymers containing side-chain azobenzene4"6,9 and stil-bene7,8,10 groups, which undergo trans -* cis isomerization by light irradiation, were very useful. Furthermore, the insertion of chiral co-units in such polymeric systems opens the possibility for studying the conformation of the above macromolecules in solution by circular dichroism (CD) measurements.11,12 By this technique poly(L-glutamates) containing side-chain stilbene7 or azobenzene4"6 chromophores have been recently shown to undergo an -helix -* random coil conformational transition photoinduced by the trans -*• cis isomerization of the photochromic groups.…”

Section: Introductionmentioning

confidence: 99%

“…Figure3. UV (---) and CD (-) spectra in the 350-250-nm region of poly(MtA-co-VS) with 41.0 mol % VS units in chloroform solution at 25 °C.…”

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confidence: 99%

Optically active polymers containing side-chain trans-stilbene chromophores directly bound to the backbone: synthesis and characterization of copolymers of (-)-menthyl acrylate with trans-4-vinylstilbene

Altomare¹,

Carlini²,

Panattoni³

et al. 1984

Macromolecules

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Optically active copolymers of (-)-menthyl acrylate (MtA) with trons-4-vinylstilbene (VS) were prepared by radical initiation over a wide range of composition. Reactivity ratios, evaluated for both comonomers, indicate that VS exhibits a higher reactivity than MtA. Average sequence lengths of the co-units and their distribution in the macromolecules were also evaluated by statistical calculations. Chiroptical properties of the side-chain trons-stilbene chromophores, combined with data of composition and distribution of monomeric units as well as UV and fluorescence measurements, suggest that the copolymer macromolecules assume conformations in solution of a prevailing single chirality due to steric effects.

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Poly(carbon suboxide): A photosensitive paramagnetic ladder polymer

Yang

Snow

Haubenstock

et al. 1978

J. Polym. Sci. Polym. Chem. Ed.

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Carbon suboxide was found to give, on photo‐ and thermal‐polymerization, a photosensitive paramagnetic polymer. Studies of the kinetics of the ESR signal growth accompanying the polymerization process complement documented results obtained from monitoring the rate of polymer production and monomer disappearance. The spin concentration of the polymer increases with higher reaction temperature, reaching 2 × 1019 spin/g at a polymerization temperature of 105°C. The paramagnetism of poly(carbon suboxide) follows the Curie—Weiss law. Relaxation behavior at room temperature and g values for the spin systems have been obtained. The 105°C polymer shows a Weiss constant equal to 17°K and an extremely narrow ESR line width, ca. 10 mG, at 5°K. The 13C coupling constant from the selectively labeled polymer indicates π‐electron delocalization over the ladder polymer. The polymer paramagnetism can be further reversibly enhanced by visible light irradiation. The steady‐state concentration of the photo‐ESR signal is proportional to the square root of incident light intensity, with a quantum yield at room temperature for charge accumulation equal to 5% at an incident light level of 1015 photons/sec‐cm2. Fluorescence and excitation spectra of the soluble fraction of poly(carbon suboxide) are presented together with the quantum yield. The polymer has also been found to be an effective photopolymerization initiator at wavelengths longer than 340 nm.

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Photoconductance of Organic Polymers

Cited by 13 publications

References 9 publications

The investigation of thermal decomposition pathway and products of poly(vinyl alcohol) by TG‐FTIR

The investigation of thermal decomposition pathway and products of poly(vinyl alcohol) by TG‐FTIR

Optically active polymers containing side-chain trans-stilbene chromophores directly bound to the backbone: synthesis and characterization of copolymers of (-)-menthyl acrylate with trans-4-vinylstilbene

Poly(carbon suboxide): A photosensitive paramagnetic ladder polymer

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