Photo-Oxidation of an IR Vulcanizate

1981 ◽  
Vol 54 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Shoichiro Yano
Keyword(s):  
Ir Spectra ◽  
Rate Constant ◽  
Wavelength Dependence ◽  
The Other ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Absorption Bands ◽  
Photo Oxidation ◽  
Other Hand ◽  
Uv And Ir Spectra

Abstract On irradiation with uv light, changes in uv and ir spectra were observed. In the uv spectrum, a minimum at 290 nm due to sulfur, dibenzothiazyl disulfide, and double bonds in the main chains disappeared initially by the consumption of them; but the minimum reappeared on further irradiation reflecting the formation of carbonyl groups. On the other hand, in the ir spectrum two absorption bands appeared at 1720 cm−1 (due to carbonyl groups) and 3450 cm−1 (due to hydroxyl groups). The latter band faded out suggesting the decomposition of hydroperoxides when the vulcanizate was kept in the dark after irradiation. From the findings of the wavelength dependence of photo-oxidation on uv and ir spectra, it was found that the degradation occurred below about 430 nm. However, investigation of the wavelength dependence of photo-oxidation by the measurement of the crosslink density gave the results that crosslinking reactions occurred below about 340 nm, scissions of C-C and polysulfide crosslinks between 340 and about 400 nm, and scissions of polysulfide crosslinks between 400 and 600 nm. These were confirmed by measurements of the dynamic modulus during irradiation. The relative modulus E′(t)/E′(0) increased on irradiation with light at 253.7 nm in a longer time region reflecting a crosslinking reaction. On the other hand, on irradiation with light above 330 nm, E′(t)/E′(0) decreased with time. Change in E′(t)/E′(0) could be represented by the equation of the first order reaction containing an exponential term and the rate constant was determined. The activation energy was calculated as 18.6 kcal/mole from the temperature dependence of the rate constant and agreed with that for scission of polysulfide crosslinks. The photodegradation of the IR vulcanizate occurred also on irradiation with visible light (> 430 nm), and the modulus decreased.

scholarly journals Effect of additional side groups on the vibrational frequencies of benzoquinone molecules

BIBECHANA ◽  
2016 ◽  
Vol 14 ◽  
pp. 66-76
Author(s):  
Nabin Kumar Raut ◽  
Hari Prasad Lamichhane
Keyword(s):  
Ir Spectra ◽  
Gas Phase ◽  
Vibrational Frequencies ◽  
The Other ◽  
Methyl Groups ◽  
Computational Investigation ◽  
Strongly Coupled ◽  
Solvent Phase ◽  
Other Hand

The present work enumerates detailed computational investigation into the IR spectra in gas phase and in solvent of 1, 4- Benzoquinone family (benzoquinone (BQ), duroquinone (DQ), plastoquinone (PQ), ubiquinone (UQ), and dimethoxy dimethyl benzoquinone (MQo)). In  the spectra of BQ, PQ, and DQ, we observed separate intense carbonyl (C=O) and C=C bands respectively around 1730 cm-1 (intense), 1645 cm-1 (weak). On the other hand, for UQ and MQo, three prominent bands around 1652, 1703, and 1733 cm-1 were observed, where two C=O modes were uncoupled but one of the carbonyl is strongly coupled with C=C vibrations. The additional methyl groups downshift the intense carbonyl bands and upshift C=C mode frequencies. The carbonyl modes further downshifted in the solvent phase calculation.BIBECHANA 14 (2017) 66-76

FT-IR Spectroscopic Study of 1,5-Pentanedithiol and 1,6-Hexanedithiol Adsorbed on NaA, CaA and NaY Zeolites

2005 ◽  
Vol 60 (8-9) ◽  
pp. 633-636 ◽  
Author(s):  
Nuri Öztürk ◽  
Çağrı Çırak ◽  
Semiha Bahçeli
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectra ◽  
Spectroscopic Study ◽  
The Other ◽  
Other Hand ◽  
Liquid Phases ◽  
Stretching Vibration ◽  
Ft Ir ◽  
Ir Spectroscopic ◽  
Nay Zeolites

The adsorption of 1,5-pentanedithiol (1,5-PDT) and 1,6-hexanedithiol (1,6-HDT) in liquid phases on NaA (or 4A-type), CaA (or 5A-type) and NaY zeolites has been studied by using infrared spectroscopy. From the IR spectra it is found that the peak positions of the symmetric as well as the antisymmetric modes of the methylene (CH2) groups are observed at almost the same band values for the title dithiolates adsorbed on the A-type and NaY zeolites. On the other hand, the weak SH stretching vibration, observed for all samples, can be attributed to the sulphure atoms of 1,5-PDT and 1,6-HDT coordinatively adsorbed on cationic sites of the zeolites.

FTIR STUDY ON MOLECULAR CONTAMINATION ON SURFACE OF OPTICAL MATERIALS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3860-3865 ◽  
Author(s):  
MASAHIRO KATOH ◽  
NOBUAKI OKANO ◽  
TOSHIHIDE HORIKAWA ◽  
TAHEI TOMIDA ◽  
NOBUNARI ITOH
Keyword(s):  
Ir Spectra ◽  
Optical Materials ◽  
Functional Group ◽  
The Other ◽  
Absorption Bands ◽  
Bending Vibration ◽  
Absorption Intensity ◽  
Stretching Vibration ◽  
Optical Disks ◽  
Molecular Contaminants

The IR spectra of the molecular contaminants on surface of optical materials were measured. The optical disks used were SiO 2, BK7 ( SiO 2 70%, B 2 O 3 10%, K 2 O 8%, N 2 O 8%), CaF 2, ZnSe and Al 2 O 3. N 2, O 2, H 2 O , and CO 2 were adopted as contamination gases. IR spectra of H 2 O (2.7kPa) on BK7 at 373K showed two absorption bands ( OH stretching vibration: around 4000cm-1-3500cm-1 and OH bending vibration: around 2000cm-1-1500cm-1). The absorption intensity decreased with a decrease in temperature and a new band (around 3250cm-1) appeared at 173K. The new band was attributed to phase transition of H 2 O . These phenomena were also observed on the other three discs, except for SiO 2. IR spectra of SiO 2 showed OH stretching band (3676cm-1). The absorption intensity decreased with a decrease in temperature. But two new bands (3720cm-1 and 3620cm-1) appeared under an atmosphere of N 2 (66.5kPa), O 2 (66.5kPa), H 2 O (2.7kPa) or CO 2 (0.7 or 13.3kPa). A similar phenomenon was also observed for BK7, which has OH group. These results suggested the functional group of SiOH interacted with contamination molecules.

Gradual H/D substitution in synthetic germanium bearing talcs: a method for infrared band assignment

Clay Minerals ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 365-374 ◽  
Author(s):  
F. Martin ◽  
S. Petit ◽  
O. Grauby ◽  
M. P. Lavie
Keyword(s):  
Ir Spectra ◽  
Spectral Shift ◽  
Hydroxyl Groups ◽  
Ir Absorption ◽  
Infrared Band ◽  
Absorption Bands ◽  
Band Assignment ◽  
Ir Bands

AbstractThe deuteration technique was used to assign unknown infrared (IR) bands of Ge-bearing talcs. Procedures to achieve partial or complete H/D replacement in synthetic Ge-bearing (Mg, Ni and Co)-talcs have been investigated. From the spectral shift of IR absorption bands in the 4000–300 cm-1 region resulting from the H-D substitution, the IR bands of vibrations of Ge-bearing talcs could be identified and synthetic Ge-bearing talcs showed significantly different IR spectra from those for Si-talcs. After deuteration of synthetic Ge-bearing talcs, the unknown bands were attributed either to hydroxyl groups or to Ge–O vibrations of the clay skeleton, and the spectra were interpreted fully.

scholarly journals COMPARATIVE INFRARED SPECTROSCOPIC STUDY OF NATURAL CA-AMPHIBOLES

2007 ◽  
Vol 40 (2) ◽  
pp. 984
Author(s):  
E. Theodosoglou ◽  
A. Koroneos ◽  
K. M. Paraskevopoulos ◽  
G. Christofides ◽  
L. Papadopoulou ◽  
...  
Keyword(s):  
Ir Spectra ◽  
Spectroscopic Study ◽  
Spectral Range ◽  
The Other ◽  
Mineral Species ◽  
Infrared Spectroscopic Study ◽  
Absorption Bands ◽  
Common Features ◽  
The Common ◽  
A Site

Powder IR spectra of natural Ca-amphiboles were studied in the spectral range 4000 to 400 cm'1. The examined samples are: actinolite, tremolite, Mg-hornblende and pargasite. According to their spectra all the minerals of the four species present common features at 3658-3660, 919, 683-687, 661-668, 505-513, 457-464 and 419 cm . Additionally to these bands, the spectra of the actinolites, tremolites and Mghornblendes present common characteristics at 3673, 1094-1098, 989-998, 951, 752-758 and 441-449 cm'1. Moreover, six absorption bands are shown in the spectra of the pargasites at 3690, 981-984, 931, 805-811, 734 and 696-698 cm'1, in addition to the common bands appeared in all Ca-amphiboles, which do not appear in the spectra of the actinolites, tremolites and Mg-hornblendes. The spectra of pargasites are remarkably different from the spectra of the other three mineral species. These discrepancies could be attributed to differences in the structure of pargasites relative to the other three species as well as to the occupancy of the A site especially with Na+.

IR spectra of methyltetrosides and their monomethyl ethers in the region of valence vibration of hydroxyl groups

1981 ◽  
Vol 46 (13) ◽  
pp. 3289-3293 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Valence Vibration ◽  
Hydroxyl Groups ◽  
Spectral Absorption ◽  
Absorption Bands ◽  
Intramolecular Hydrogen Bonds ◽  
Individual Bands ◽  
Intramolecular Hydrogen

IR Spectral absorption bands ν(OH) (3 700 to 3 400 cm-1) of the both anomers of methyl D-threofuranoside, methyl-D-erythrofuranoside, and their monomethyl ethers have been studied in dilute tetrachloromethane solution. For these 11 compounds positions and intensities of individual bands are discussed with respect to possible formation of intramolecular hydrogen bonds.

Hygroscopicity of resorcinol-formaldehyde resin and aqueous vinyl polymer-isocyanate resin in high humidity

Holzforschung ◽  
2005 ◽  
Vol 59 (3) ◽  
pp. 342-346 ◽  
Author(s):  
Junko Miyazaki ◽  
Takato Nakano
Keyword(s):  
Mechanical Properties ◽  
Adsorption Isotherms ◽  
The Other ◽  
Formaldehyde Resin ◽  
Hydroxyl Groups ◽  
High Humidity ◽  
Resorcinol Formaldehyde ◽  
Other Hand ◽  
Vinyl Polymer

Abstract The hygroscopicity and hygro-mechanical properties of the adhesives, resorcinol-formaldehyde (RF) resin and aqueous vinyl polymer-isocyanate (API) resin have been examined. Adsorption isotherms for cured RF and API resins with various degrees of crosslinking showed that the hygroscopicity of both resins decreased as the curing reactions proceeded, although the mechanisms for these decreases differed. In RF resins cured with a large amount of hardener, a highly crosslinked structure is formed, so swelling is limited by the network. Thus, the hygroscopicity of cured RF resins decreases due to the restricted swelling, while the number of hydroxyl groups, another source of hygroscopicity, are not changed by the curing. On the other hand, swelling in API resins cured with a large amount of hardener is not completely inhibited because of long segments between the crosslinks. The hygroscopicity of cured API resins is lowered as the curing extent increased, since this reaction decreases the number of hydroxyl groups.

Sodium Exchange in the Cytoplasm and Nucleus of Amphibian Oocytes

1974 ◽  
Vol 16 (2) ◽  
pp. 465-471
Author(s):  
T. J. CENTURY ◽  
S. B. HOROWITZ
Keyword(s):  
Low Temperature ◽  
Cell Surface ◽  
Rate Constant ◽  
Rana Pipiens ◽  
The Other ◽  
Cytoplasmic Fraction ◽  
Single Fraction ◽  
Ringer’S Solution ◽  
Other Hand ◽  
Sodium Exchange

Oocytes of Rana pipiens were incubated in 22Na-Ringer's solution and 22Na-23Na exchange in the nucleus and cytoplasm followed by low-temperature microdissection. Cytoplasmic sodium consists of 2 kinetic fractions: the larger (88%) slowly exchanging (t½ ∼ 2 days), and the smaller (12%) rapidly exchanging (t½ ∼ 53 min). Nuclear sodium consists of a single fraction whose concentration is similar and whose rate constant is identical with that of the rapidly exchanging cytoplasmic fraction. Our findings are consistent with a model of compartmentalization in which rapidly exchanging sodium is nearly uniformly distributed in the water of the nucleus and cytoplasm and its exchange limited by movement through the cell surface. On the other hand, slowly exchanging sodium is restricted to the cytoplasm, sorbed to or sequestered in some as yet unidentified cytoplasmic constituent.

scholarly journals Reactivity of T-Nb2O5 or H-Nb2O5 towards V2O5. Synthesis in the solid state and properties of V4Nb18O55

2009 ◽  
Vol 7 (2) ◽  
pp. 222-227 ◽  
Author(s):  
Piotr Tabero ◽  
Elzbieta Filipek ◽  
Mateusz Piz
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Solid State ◽  
Ir Spectra ◽  
Ir Spectrum ◽  
The Other ◽  
Other Hand ◽  
Structural Relations

AbstractThe IR spectrum of V4Nb18O55 has been compared with the IR spectra of selected niobates of known structures to show structural relations between these compounds. This comparison shows that V4Nb18O55 has crystal structure related to T-Nb2O5, W16Nb18O94 and Ba2NaNb5O15. On the other hand, reaction between V2O5 and H-Nb2O5 yields a solid solution of V2O5 in VNb9O25. It has been proposed two models of synthesized solid solution with formulas V1+xNb9-xO25 or V1+xNb9O25+5x/2.Independently of Nb2O5 polymorph, used for synthesis, the metastable compound VNbO5 cannot be synthesized in the solid state below 650°C

scholarly journals Study of Struvite Crystal Growth with The Addition of Tartaric Acid

2021 ◽  
Vol 328 ◽  
pp. 01003
Author(s):  
Dyah Suci Perwitasari ◽  
Sintha Soraya Santi ◽  
Stefanus Muryanto ◽  
J Jamari ◽  
AP Bayuseno
Keyword(s):  
Aqueous Solution ◽  
Crystal Growth ◽  
Tartaric Acid ◽  
Rate Constant ◽  
The Other ◽  
Molar Ratio ◽  
Other Hand ◽  
Constant Rate ◽  
Manufacture Industry ◽  
Crystal Mass

The purpose of this study was to study the growth of struvite crystals from the effect of adding tartaric acid additives to an aqueous solution containing Mg2+, NH4+, and PO43-with a molar ratio of 1:1:1. The results of the study, it was found that the more the concentration of tartaric acid additive was added, it got smaller the rate constant was. By decreasing the value of the constant rate, the growth of struvite crystals also decreased then the growth of struvite crystals became inhibited. On the other hand, struvite has the potential to be used as a fertilizer. The concentration of tartaric acid also had a significant effect on controlling the production of struvite. The optimum crystal mass was obtained at a concentration of 20 ppm tartaric acid, a temperature of 40oC and a stirrer rotation of 300 rpm so that it can be applied in manufacture industry of struvite fertilizer.

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