Infrared spectroscopy cellulose

The acetyl content of cellulose acetate may be calculated by difference from the hydroxyl content, which is usually determined by carbanilation of the ester hydroxy groups in pyridine solvent with phenyl isocyanate [103-71-9J, followed by measurement of uv absorption of the combined carbanilate. Methods for determining cellulose ester hydroxyl content by near-infrared spectroscopy (111) and acid content by nmr spectroscopy (112) and pyrolysis gas chromatography (113) have been reported. 

The phase composition of glycine crystal forms during the drying step of a wet granulation process has been studied, and a model developed for the phase conversion reactions [88], X-ray powder diffraction was used for qualitative analysis, and near-infrared spectroscopy for quantitative analysis. It was shown that when glycine was wet granulated with microcrystalline cellulose, the more rapidly the granulation... 

Rossi et al. [30] evaluated rheologically mucins of different origin with polyacrylic acid and sodium carboxymethyl cellulose. The same group also reported a novel rheological approach based on a stationary viscoelastic test (creep test) to describe the interaction between mucoadhesive polymers and mucins [31,32]. Jabbari et al. [33] used attenuated total-reflection infrared spectroscopy to investigate the ehain interpenetration of polyaciylic acid in the mucin interface. 

A. Gupta, G.E. Peck, R.W. Miller and K.R. Morris, Influence of ambient moisture on the compaction behavior of microcrystalline cellulose powder undergoing uni-axial compression and roller compaction a comparative study using near-infrared spectroscopy, J. Pharm. Sci., 94(10), 2301-2313 (2005). 

Proof of grafting was presented through comparison of the solubilities of their saponified vinyl acetate and cellulose grafts and of the physical mixtures of the corresponding homopolymers. While from a cupriethyl-enediamin solution of the physical mixture pure cellulose is precipitated on acidification, the precipitate from the graft solution always contains constant amounts of polyvinyl alcohol, as proven by infrared spectroscopy. 

Vasiliu, Feldman, and Simionescu (67) grafted acrylonitrile onto cotton and poplar fluff cellulose which were ozonized before the grafting reaction. The authors characterized the graft copolymer by nitrogen analysis and by infrared spectroscopy and studied their behaviour towards acids, bases and swelling agents. 

Deters, and Huang (129) describe the formation of graft copolymers of cellulose triacetate and vinyl chloride in vibratory mill treatments. Through hydrolytic degradation of the triacetate backbone, they isolated the polyvinyl chloride side chains and characterized them by infrared spectroscopy and cryoscopic molecular weight determination. The length of the side chains has been found to be between 15 and 30 vinyl chloride units. 

Graft and block copolymers of cotton cellulose, in fiber, yam, and fabric forms, were prepared by free-radical initiated copolymerization reactions of vinyl monomers with cellulose. The properties of the fibrous cellulose-polyvinyl copolymers were evaluated by solubility, ESR, and infrared spectroscopy, light, electron, and scanning electron microscopy, fractional separation, thermal analysis, and physical properties, including textile properties. Generally, the textile properties of the fibrous copolymers were improved as compared with the properties of cotton products. 

Applications of ESR spectroscopy to investigations of free-radical initiated copolymerization reactions of cellulose with vinyl monomers have been reported (1, 2). NMR and infrared spectroscopy have been used to examine products obtained from degradation of cellulose copolymers to characterize the nature of the chemical bonds between cellulose and polyvinyl polymer (35, 42). Covalent bonds were indicated in most cases. 

The degradation of the cellulose fraction of the copolymer and subsequent recovery of the polyvinyl polymer have often been used to characterize the polymer. For example, cellulose may be acetylated and acid hydrolyzed to remove it from the copolymer. Then the recovered polymer can be dissolved, in solvent normally used for the polymer, and i the molecular weight of the polymer determined viscometrically (12, 42). As reported previously for polymers, such as polyacrylonitrile, a functional group on the polymer may be altered during the fractionating. These changes have been determined by infrared spectroscopy. For free-... 

Gustafsson, C. Nystrom, C. Lennholm, H. etal., Characteristics of hydroxypropyl methyl-cellulose influencing compactability and prediction of particle and tablet properties by infrared spectroscopy J. Pharm. Sci. 2003, 92, 460-470. 

O Brien and Hartman (26) studied the interface of a model system—epoxy resin, regenerated cellulose fibers—by attenuated total reflectance infrared spectroscopy. They compared spectra of the components to spectra of epoxy cured on cellulose and found for the mixture a diminished hydroxyl absorption (3,350 cm 1) and C-0 stretching (1,050 cm"1), and disappearance of the epoxy band (915 cm 1). From this they concluded that covalent bonding does occur between the epoxide groups and cellulose hydroxyls. 

Harbour JR, Hopper MA, Marchessault RH, Dobbin CJ, Anczurowski E (1985) Photoacoustic spectroscopy of cellulose, paper and wood J Pulp Pap Sci 11 J42-J47 Hauser M, Oelichmann J (1988) A critical comparison of solid sample preparation techniques in infrared spectroscopy Microchim Acta (Wien), Spec Issue, I 39-43 Hergert HL (1971) Infared spectra In Sarkanen KV, Ludwig CH (eds) Lignins Occurrence, formation, structure and reactions Wiley-Interscience, New York, 267-293 Hirschfeld T (1987) In McClure GL (ed) Computerized quantitative infrared analysis ASTM, Philadelphia, 169-179... 

From a study of 2,3-anhydro derivative of cellulose by infrared spectroscopy combined with the determination of the monosaccharide composition of the products of its acetylation and interaction with sodium methylate, we conclude that the mixed polysacdiaride synthesized contains glucose and 2,3-anhydromannose units. 

Studies of cellulose anhydro derivatives containing 2,3- and 3,6-anhydro rings by means of infrared spectroscopy (14,15) have made it possible to draw inferences about the nature of the conformational... 

Horlick G (1968) Introduction to Fourier transform spectroscopy. Appl Spectrosc 22 617-626 Kawamura L, Higuchi T (1964a) Comparative studies of milled wood lignins from different taxonomical origins by infrared spectroscopy. In Grenoble Symposium 1964, Chimie et biochimie de la lignine, de la cellulose et des hemicelluloses. Lcs Imprimeries Reunies de Chambery, Chambery, 439-456... 

The various functional groups were also identified by independent, chemical methods used in organic chemistry [38, 42]. Infrared spectroscopy has also been used for the identification of surface groups. In the beginning, the method suffered from the strong absorption of carbon materials, and poor spectra were obtained. Zawadzki used thin films of cellulose carbonized at 600° C to get acceptable transmission spectra [50], but it is debatable whether such chars are really representative for carbons. It was not possible to heat the cellulose chars... 

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