02102nas a2200229   4500008004100000022001400041245010400055210006900159260009900228300001200327490000700339520126100346653001301607653002501620653001801645653001501663653000801678653001001686100002101696700002301717856013201740       2008                        eng d  a0144-861700aMorphological study of heavy metal complexes of chitosan and crosslinked chitosans by SEM and WAXRD0 aMorphological study of heavy metal complexes of chitosan and cro  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcMAR  a698-7020 v713 a<p>Metal complexes of salts of Hg, Cu, Cd, Pb, Zn, and Mn with chitosan and crosslinked chitosans were prepared, and their morphologies were studied using scanning electron microscopy and wide angle X-ray diffraction. The metal ions which were specifically and strongly complexed to the amino functions of chitosans, like Hg, showed smooth surface morphology inspite of large number of ions complexed (372 mg/g of chitosan). The presence of metal ions on the surface of the chitosans could be detected with decrease in metal ion binding, in the following sequence Hg &gt; Cu &gt; Cd &gt; Zn &gt; Pb &gt; Mn. Particularly in the case of Pb ions, the presence of these ions is clearly seen on the surface of the polymer by SEM. The number of ions of Mn complexed on the polymers was too few (5 mg/g of chitosan) to be visible. SEM of Hg and Cu complexes do not show the ``holes'' observed in the crosslinked polymers as they bind specifically to amino groups of chitosan, but for Cd, Zn, Mn, and Pb complexes, these ``holes'' are clearly visible. These results are also in agreement with the morphologies studied by WAXRD. The metal complexation data for each of these metal ions was also in the same sequence. (c) 2007 Elsevier Ltd. All rights reserved.</p>10aChitosan10aCrosslinked chitosan10ametal complex10aMorphology10aSEM10aWAXRD1 aTrimukhe, K., D.1 aVarma, Anjanikumar  uhttps://library.ncl.res.in/content/morphological-study-heavy-metal-complexes-chitosan-and-crosslinked-chitosans-sem-and-waxrd-002266nas a2200229   4500008004100000022001400041245015400055210006900209260009900278300001200377490000800389520136000397653002101757653001401778653001801792653000801810653001001818100002501828700003501853700002301888856012501911       2014                        eng d  a0144-861700aSupramolecular transitions in native cellulose-I during progressive oxidation reaction leading to quasi-spherical nanoparticles of 6-carboxycellulose0 aSupramolecular transitions in native celluloseI during progressi  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcNOV  a615-6230 v1133 a<p>Cellulose-I swells considerably in phosphoric acid, and converts to amorphous cellulose via a cellulose-II transition state. Controlled oxidation of cellulose-I to 6-carboxycellulose (6CC) using HNO3-H3PO4-NaNO2 oxidation system led to the selective production of 6CC's of varying carboxyl contents (1.7-22%) as well as various shapes and sizes (macro-sized fibrils of several micron length and/or spherical nanoparticles of 25-35 nm), depending on the reaction conditions. 6CC's having less than 14% carboxyl content were largely in cellulose-II form (WAXRD values in-between cellulose I and cellulose II), whereas at 14-22% the 6CC's were largely amorphous; only trace crystallinity was observed at 19% and 22% carboxyl 6CC. Spherical nanoparticles retained a high degree of crystallinity having cellulose-I structure, whereas the macro-sized fibrils were largely converted to cellulose-II structure. Analysis by WAXRD as well as by CP-MAS C-13 NMR studies gave similar conclusions. Reduced molecular weight with progressive oxidation, including presence of oligomers, was also evident from an increase in the reducing-end carbon peak at similar to 92 ppm. For high oxidation levels (&gt;14%) the NMR 92-96 ppm peaks disappeared on extracting with dilute alkali, due to soluble oligomers being removed. (C) 2014 Elsevier Ltd. All rights reserved.</p>10aCarboxycellulose10acellulose10aNanoparticles10aNMR10aWAXRD1 aSharma, Priyanka, R.1 aRajamohanan, Pattuparambil, R.1 aVarma, Anjanikumar  uhttps://library.ncl.res.in/content/supramolecular-transitions-native-cellulose-i-during-progressive-oxidation-reaction-0