| Autor: |
Moore Ii JP; Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR 72701, USA., Dachavaram SS; Department of Pharmaceutical Sciences College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA., Bommagani S; Department of Pharmaceutical Sciences College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA., Penthala NR; Department of Pharmaceutical Sciences College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA., Venkatraman P; Material Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA., Foster EJ; Material Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA.; Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T1Z3, Canada., Crooks PA; Department of Pharmaceutical Sciences College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA., A Hestekin J; Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR 72701, USA. |
| Abstrakt: |
The 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation of cellulose, when mediated with Oxone ® (KHSO 5 ), can be performed simply and under mild conditions. Furthermore, the products of the reaction can be isolated into two major components: Oxone ® -mediated TEMPO-oxidized cellulose nanomaterials Form I and Form II (OTO-CNM Form I and Form II). This study focuses on the characterization of the properties of OTO-CNMs. Nanoparticle-sized cellulose fibers of 5 and 16 nm, respectively, were confirmed through electron microscopy. Infrared spectroscopy showed that the most carboxylation presented in Form II. Conductometric titration showed a two-fold increase in carboxylation from Form I (800 mmol/kg) to Form II (1600 mmol/kg). OTO-CNMs showed cellulose crystallinity in the range of 64-68% and crystallite sizes of 1.4-3.3 nm, as shown through XRD. OTO-CNMs show controlled variability in hydrophilicity with contact angles ranging from 16 to 32°, within or below the 26-47° reported in the literature for TEMPO-oxidized CNMs. Newly discovered OTO-CNM Form II shows enhanced hydrophilic properties as well as unique crystallinity and chemical functionalization in the field of bio-sourced material and nanocomposites. |
