EPR spectroscopy applied to the study of the TEMPO mediated oxidation of nanocellulose"

J. M. BUFFA; M.A.GRELA; ARANGUREN. MIRTA I.; V. MUCCI

CARBOHYDRATE POLYMERS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2016

0144-8617

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Buffa, María Alejandra Grela, Mirta I. Aranguren, VerónicaMucci, "EPR spectroscopy applied to the study of the TEMPO mediatedoxidation of nanocellulose".  Carbohydrate Polymers, 136, 744-749 (January 2016)  doi:10.1016/j.carbpol.2015.09.094&amp;lt;!-- /* Font Definitions */@font-face{font-family:Times;panose-1:2 0 5 0 0 0 0 0 0 0;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;}@font-face{font-family:Cambria;panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;}@font-face{font-family:Times-Roman;panose-1:0 0 0 0 0 0 0 0 0 0;mso-font-alt:Times;mso-font-charset:77;mso-generic-font-family:auto;mso-font-format:other;mso-font-pitch:auto;mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-parent:"";margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;margin-left:0cm;mso-pagination:widow-orphan;font-size:12.0pt;font-family:"Times New Roman";mso-ascii-font-family:Times;mso-fareast-font-family:Cambria;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Times;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}@page Section1{size:612.0pt 792.0pt;margin:72.0pt 90.0pt 72.0pt 90.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.Section1{page:Section1;}--&amp;gt;Twodifferent methods of pH control were used in the synthesis of2,2,6,6-tetramethylpiperidine-1- oxyl (TEMPO) oxidized cellulose nanocrystals (CNC) and thereaction kinetics and degree of oxidation were investigated. In method I the media pH was controlledby addition of NaOH solution.The effect of the oxidant concentration (sodium hypochloride, NaClO) on thefinal degree ofoxidation and cristallinity of the samples was investigated. Conditions forobtaining an optimum balancebetween high cristallinity and degree of oxidation were selected from thoseresults. In methodII, pH was fixed by using a buffer solution. Electron spin resonance (ESR)spectroscopy offereddirect information of the decay of TEMPO concentration under these conditions.The kinetics of thereaction was determined, finding a direct correlation between these results andthose corresponding to thedecay of the NaClO concentration and the advance of the CNC degree of oxidation. Differences foundbetween the two methods were analyzed.