TEMPO-mediated oxidation has been reported to effectively convert C6 primary hydroxyl groups to carboxyl groups for better water-solubility. However, the pH decreases continuously during the oxidation process, and it is therefore difficult to maintain the stability of the reaction. The control of pH at a constant level throughout the oxidation process is a complicated task. The applicability of...

In this study, oxidized maltodextrins with a high concentration of carboxyl groups were produced using CuSO4 as catalyst and H2O2 an eco-friendly oxidant. Infrared spectroscopy, proton-nuclear magnetic resonance thermogravimetric analysis utilized to examine the structure properties maltodextrins. The reaction conditions optimized in terms oxidant content, temperature, pH, time. prepared maltod...

Carboxyl and carboxylate groups form important supramolecular motifs (synthons). Besides carboxyl cyclic dimers, carboxyl and carboxylate groups can associate through a single hydrogen bond. Carboxylic groups can further form polymeric-like catemer chains within crystals. To date, no exhaustive classification of these motifs has been established. In this work, 17 association types were identifi...

the effect of fiber surface modification on physical and mechanical properties of kraft pulp wasstudied with and without chitosan. first, the amount of carboxyl groups of kraft pulp at differentaddition levels (0, 2, 3, 4 and 6%) of hydrogen peroxide was determined by means of methylene bluetest. then, the samples containing the highest carboxyl groups were treated at ph=8.5 with chitosan at0.7...

Glutaraldehyde (GA) fixation of bioprosthetic tissue is a well adapted technique, with commercial products on the market for almost 40 years. Amine groups present in tissue react with GA to form different types of cross-links. An estimation of the degree of cross-linking of the tissue can be obtained by measuring the concentration of residual amine groups, which is frequently carried out with t...

Carboxylic acid groups were introduced onto thermomechanical pulp (TMP) long fiber surfaces by 2,2,6,6,tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation in the present study. The number of introduced carboxylic groups was closely related to the NaClO dosage, and more flexible fibers with lower curl and kink index were generated. Lignin was dissolved during the TEMPO-mediated oxida...