the effect of bleaching with sodium hypochlorite, as one of the most important parameters in obtaining optimal alpha cellulose pulp from cotton linter was studied. in this respect, unbleached cotton linter pulp was prepared from parchin chemical industry co., bleached by hea sequence in ph=9, 11 and 13; and then its chemical structures properties such as alpha cellulose, degree of polymerizatio...

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...