Infrared Spectroscopy

Barnes, R. B.; Gore, R. C.

doi:10.1021/ac60025a003

Cited by 16 publications

(11 citation statements)

References 89 publications

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“…The intense absorption at 6.1 ,u is attributed to the carbonyl group, which usually absorbs at 5.76 to 5.84 microns but is displaced to longer wav elength in nylon 66 and amides in general probably as a re6ult of interaction between the carbonyl and imine groups [42]. The intense absorption at 6.46 ,u may result from N-H bending and could cause a harmonic effect at 3.2 ,u. The doublet band at 6.8 and 7.05 ,u has been observed in diallyl adipate [45]. This pair of bands may b e connected with CH2 deformations, such as -CH2 -and =CH 2 [42].…”

Section: (B) Pyrolysismentioning

confidence: 95%

“…A band at 7.3 Jk is attributed, in some cases, to -CH 3 deformation. Single bond stretching might absorb in this region, and the band has b een observed in diallyl adipate [45]. Thompson and Torkington [42] claim that in polyamides "much of the absorp tion between 8.34 and 5.88 Jk must be due to vibrations of the -C-CO -NH -C-part of the structure" .…”

Section: (B) Pyrolysismentioning

confidence: 99%

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Mechanism of the degradation of polyamides

Achhammer¹,

Reinhart²,

Kline³

1951

J. RES. NATL. BUR. STAN.

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Films of polyamides were exposed to heat, ultraviolet radiant energy, and different atmospheric conditions. The degradation products were collected in some cases and analyzed by mass spectrometric techniques. The unexposed and exposed specimens were examined by the following techniques to obtain information concerning the changes in chemical and physical structure of the polymer: infrared absorption, ultraviolet absorption , viscosity of solutions, measurement of dielectric constant and dissipation factor, photomicrography, X-ray diffraction, electron microscopy, electron diffraction, and effect of organic liquids. In addition, pyrolysis studies were made and some physical properties were determined. The results of the investigation show clearly that no single method gives a complete picture but that the results from several of the methods give an insight into the mechanism of degradation of poly ami des.Polyamide molecules are relatively unaffected by exposure to moderate temperature (60 0 C). However, loss of water and other volatile materials may cause changes in physcial properties. The effects of exposure to ultraviolet radiant energy are more pronounced, and degradation of the polyamide molecule occurs with accompanying loss of water and other volatile materials that act as plasticizers.The results of this inves tigation show that the general course of the degradation of polyamides is as follows :1. The polymer mol ecules break at the C -N bond of the peptide group creating smaller polymer molecules with the same unit of chemical structure. The fragments broken out are evolved as carbon dioxide, carbon monoxide, water, and hydrocarbons.2. The degree of crystallinity or local order changes, including alterations in hydrocarbon packing, dipole rearrangement, and hydrogen bridging.3. The amount of strongly bound water and/or organic liquids changes. These materials are probably bound by hydrogen bridging to the oxygen of the peptide group. They act as plasticizers for the polyamides. r. IntroductionOne of the major problems facing the plastics industry is the degradation of some plastics when exposed to certain service conditions. This problem has been investigated extensively by accelerated tests involving one or more physical properties. While empirical investigations of this type give information of value, they yield little or no information on the basic changes in the material. As a result, the value of the information now aVi),ilable is not only limited, but in too many instances the information cannot be used to predict behavior in actual service [1).1 The physical changes observed during degradation may result from (1) changes in the chemical structure of the plastic material, and (2) loss or changes in the compounding ingredients. The logical method of attack is to determine the specific chemical reactions involved in the degradation of the plastic and how these reactions are affected by the intensity of the conditions encountered.The degradation of the plastic type of polyamides was investigated as p...

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Section: (B) Pyrolysismentioning

confidence: 95%

Section: (B) Pyrolysismentioning

confidence: 99%

Mechanism of the degradation of polyamides

Achhammer¹,

Reinhart²,

Kline³

1951

J. RES. NATL. BUR. STAN.

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“…Literally hundreds of papers have appeared in the literature in which the influence of hydrogen bonding on specific absorption 1naxima has been recorded (4,34,35,63). Infrared data on hydrogen bonds in organic and inorga nic compounds and mixtures have been profuse.…”

Section: Part Tl\0: Infrared Spectroscopic Study Of the Nature Ofmentioning

confidence: 99%

Inner-Complex Compounds of Alicyclic Vicdioximes

Voter¹,

Banks²

1951

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The need for a water-soluble vic-dioxime as an analytical reagent for nickel(II) and palladium(II) ions has long been evident. Thus, a preparation and investigation of some alicyclic vic-dioximes as possible watersoluble reagents was undertaken. Secondly, in order to obtain a better understanding of the structure of the inner-complex compounds that the vic-dioximes form with certain ions, an infrared spectroscopic study of the nature of the hydrogen bonds in these inner-complex compounds was made.

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“…As the frequ ency and . intensity of this absorption are normally influenced by the adjacent molecular structure [6,7], ketonic, aldehydic, and carbox-ylic carbonyl groups of oxidized celluloses might reasonably be expected to absorb at different wavelengths.…”

Section: Introductionmentioning

confidence: 99%

“…This law states that log 10/1= ked, where 10 and I are the intensities, respectively, of the radiant energy of a given wavelength falling upon and passing through the sample, k is an absorption coefficient characteristic of the sample, c is a concentration, and d is the cell thickness. In the analysis of discontinuous solids, such as the oxidized celluloses, the necessity for measuring cell thickness is usually avoided by the addition of a properly chosen solid reference material in a fixed ratio to the total sample [7,10]. Spectrophotometric measurements on mixtures of the reference material with samples containing varying and known amounts of the component of interest supply the data required for the construction of a working curve to be used in the analysis of unlmowns.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric determination of carboxyl in cellulose

Forziati¹,

Rowen²,

Plyler³

1951

J. RES. NATL. BUR. STAN.

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A m ethod that uses the intensity of the absorption of the oxidized cell uloses at 5.S microns as a measure of their carboxyl content is d escribed. The analyses are canied out on mineral oil slurries of 1:1 mixtures of fine ly divided polystyrene and cellulose. The absorption of the polystyrene at 6.2 microns is used as a reference band, t hus obviating the necessity of accurately controlling the thickness of the absorption cell. The method gives results that agree fairly well with those obtained by the calcium acetate method and can be used to detect a s little as 0.1 millimole of carboxyl per gram of cellulose.

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Infrared Spectroscopy

Cited by 16 publications

References 89 publications

Mechanism of the degradation of polyamides

Mechanism of the degradation of polyamides

Inner-Complex Compounds of Alicyclic Vicdioximes

Spectrophotometric determination of carboxyl in cellulose

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