Cotton cellulose spectra

Figure 7. Changes in ESR spectra of cotton cellulose mechanoradicals. Key a, initial spectrum observed at 77 K immediately after milling for 4 h at 298 K b, cotton cellulose after milling was contacted with methyl methacrylate and warmed at 298 K for 2 min c, 5 min d, 10 min recorded at 77 K.

A series of eight THPOH-NH3 treated fabrics was examined. The spectra of the untreated cotton, the treated cotton, and the difference spectrum obtained subtracting the untreated cellulose spectrum from that of the treated fabric as obtained on the FTIR are shown In Figure 2. It Is very difficult to distinguish the 1655... 

Finally, the spectrum of the Cladophora cellulose which survived the strong acid hydrolysis closely resembled the cotton hydrocellulose spectrum except that the resolution was much better in the former spectrum. A contrast in resolution is consistent with a difference in the average lateral dimensions for the crystallites this difference is corroborated by electron microscopy. The close similarity of multiplet relative intensities in these two samples, in spite of their different crystallite surface-to-volume ratios verifies that surface resoncinces cire not determining the apparent multiplet intensities, particularly, for the 88-92 ppm region of the C l resonance. 

Figure 6b shows the spectrum of the crystalline component of cotton soaked in H OCwater content=161%), which was obtained by Torchia s pulse sequence(27,28). The delay time between two ir/2 pulses in the pulse sequence was set to be 100 s. As is clearly seen, the spectrum shown in Figure 6b reflects the components corresponding to the downfield sharp lines of C4 and C6 carbons in the whole spectrum shown in Figure 6a. A similar crystalline spectrum was obtained by others(29) using almost the same technique. On the other hand. Figure 6c indicates the spectrum of the noncrystalline component of the cotton cellulose, which was obtained by subtracting the spectrum of the crystalline component shown in Figure 6b from the whole spectrum shown in Figure 6a. This spectrum evidently corresponds to the components associated with the upfield broad resonances of C4 and C6 carbons.

Figure 29 Stackplot spectra of medieval parchment vellum from cantoral No. 3 in the Biblioteca at Valladolid the spectrum of the repaired vellum indicates no proteinaceous features and a clear match with the cellulose spectrum from a natural cotton boll. Wave-number region 2700-...

FT-Raman has been used as an alternative to TG techniques to determine filler content in HDPE/ CaC03 composites and provides comparable results [400]. As most pigments (apart Ifom carbon-black) and glass are poor Raman scatterers, in principle Raman spectra are obtainable Ifom these samples without removal of the fillers or difficult sample preparation. Conventional visible Raman spectroscopy has failed in attempting to analyse dyesmffs. Conventional Raman spectra of dyed textiles tend to be dominated by the (fluorescent) spectrum of the dye [401]. Consequently, FT-Raman spectroscopy may be a more useful tool for direct observation of low levels of dyestuffs in polymeric materials. Indeed, by using NIR excitation dramatic improvements in the Raman spectra of these dyes can be achieved [392]. FT-Raman was quite useful for the discrimination of differently dyed cotton-cellulose fabrics with the bifunctional reactive dye Cibacron C, provided that the interpretation was facilitated by chemometrics [402]. Schrader et al. [403] have used FT-Raman spectra to distinguish non-destructively the main dye components in historical textiles. Bourgeois et al. [401] have successfully used FT-Raman in the characterisation of... 

Figure 7.2 Solid-state NMR spectrum of initial (a] and amorphized (b] cotton cellulose.

Vertical surface collectors can readily provide information on relative drift (e.g., the amount of drift from one field trial compared to another). However, it is difficult to obtain absolute data unless the precise collection characteristics are known for the droplet size spectrum at the point of spray collection, wind speed and air turbulence intensity. " The SDTF conducted studies in wind tunnels to compare the collection efficiency of different types of drift collector used in its field studies. These studies showed that collection efficiency on strings was several orders of magnitude higher for 0.8-mm diameter cotton string than for 2-mm diameter polyethylene line and vertical o -cellulose strips or squares. The higher collection efficiency for the cotton... 

A new, crystalline modification termed cellulose-x has been reported. It is obtained by treating cotton or wood pulp with concentrated hydrochloric acid at room temperature, or, in a particularly pure form, by the use of phosphoric acid at 50°. A definite interpretation of the structure cannot be given at present, but x-ray results indicate that a unit cell having the same dimensions as that of the high-temperature form of cellulose [cellulose IV (unit-cell dimensions a = 8.12, 6 = 10.3, c = 7.99 A. /8 = 90°) 2 is the most probable one, but having the pyranose rings of the central chain displaced by half a D-glucose residue with respect to the corner chains. The infrared spectrum lies between those of cellulose II and cellulose IV. 

Figure 3 The CCP/MAS spectrum of cotton linters. The horizontal bars indicate the spectral ranges of the corresponding sites in the anhydroglucose monomer unit of cellulose.

Figure 9 raises an Important question concerning crystalline polymorphy in the native celluloses. The hypothesis that higher plant celluloses like cotton and ramie are crystalline composites was suggested, in part, by the outer doublet and the sharper central feature of the Cl resonance in spectrum 9A. However, comparison of spectra 9A and 9C shows the central peak at Cl to be less intense at 200s compared with 1 ms, while the shape of the crystalline resonance at C4 remains constant. Since carbons C1-C5 relax at very nearly the same rates (32) in a T experiment, it is very likely that the signals for each of these carbons in... 

For most textile uses, a DS <1 is desirable. Cyanoethylation can impart a wide variety of properties to the cotton fabric, such as rot resistance, heat and acid resistance, and receptivity to acid and acetate dyes. Acrylonitrile and acrylonitrile polymers (qv) has also been radiation-pol5unerized onto cotton with a °Co source. Microscopical examination of ultrathin sections of the product shows that the location of the polymer is within the fiber (120). Examination of the ir spectrum of cotton-containing polymerized acrylonitrile indicates that grafliing occurs at the hydroxyl site of the cellulose (121). Another monomer grafted onto cellulose by irradiation is styrene polymers (qv). Chemical properties, mechanisms, and textile properties of these grafted poisoners of cellulose have been summarized... 

---