The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Regenerated cellulosic fibres and comparative materials were studied in the hydrated state by low-resolution proton NMR. Experiments at variable pH and temperatures have shown that the shortened T 2 relaxation times of water within fully swollen cellulosic fibres are dominated by proton exchange with accessible cellulose hydroxyl groups. Proton exchange is accelerated by both acid and base...
Carbon-13 high-resolution solid-state NMR techniques have been invaluable in elucidating the structure of regenerated cellulosic materials. Studies of a range of fibres have shown systematic changes in chemical shifts, which can be related to the influences of physical processing or chemical modification. A constrained curve fitting method has been applied, where the C4 spectral envelope is represented...
Complementary isotherm and NMR-relaxation techniques have been used to characterise a controlled series of solvent-spun (lyocell) fibre samples, treated with a methylol-urea type resin. The incorporation of cross-links reduces overall fibre swelling, causing a loss of both large and small pores, a reduction of volume accessible to large dye molecules, and a reduction in the free energy of the dye...
Cellulose I, mainly as ramie or as Avicel microcrystalline cellulose, has been monitored by optical microscopy and by 13C CPMAS NMR, over the course of its dissolution in hot N-methylmorpholine N-oxide solvent. Its interaction with the near-solvent N-ethylmorpholine N-oxide and related non-solvents has also been investigated. NMR shows that N-methylmorpholine N-oxide partly converts crystalline cellulose...
Data from 3 J HCCH and 3 J HCOC couplings in 1,2-dimethoxyethane and bis-(2-methoxyethyl)ether, plus 3 J HCCH in poly(ethylene oxide), have been obtained in five solvents by iterative fitting. The resulting proportions of gauche rotamers are higher than previous estimates, and higher still after allowance...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.