TY - JOUR
T1 - Quantification of cellulose nanowhiskers sulfate esterification levels
AU - Gu, Jin
AU - Catchmark, Jeffrey M.
AU - Kaiser, Edward Q.
AU - Archibald, Douglas D.
N1 - Funding Information:
This research was supported as part of The Center for LignoCellulose Structure and Formation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science under Award Number DE-SC0001090. SEM, XPS and XRD techniques were supported by the Pennsylvania State University Materials Research Institute Nanofabrication Lab and the National Science Foundation Cooperative Agreement No. ECS-0335765. The authors appreciate Dr. Alan Esker's suggestions on procedures for cellulose desulfation. Special thanks to Jing Guo who measured the specific surface area of CNWs. The authors are grateful to Dr. Ronald Wasco for assistance with CGA.
PY - 2013/2/15
Y1 - 2013/2/15
N2 - Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, combustion gas analysis and N2 adsorption were used to quantify the degree of desulfation of cellulose nanowhiskers (CNWs). CNWs were produced by hydrolyzing cotton cellulose with sulfuric acid or hydrochloric acid. Hydrochloric acid treatment did not result in any cellulose chemical modification. Hydrolysis using H2SO4 introduced sulfate groups onto the cellulose surface. Our results indicate that commercial cotton cellulose as received contained sulfur. The sulfur content of H 2SO4-prepared CNWs was higher than that exhibited by the original cellulose due to the esterification process. Two desulfation methods, acid-catalyzed and solvolytic desulfation, have been explored to remove the sulfate groups. Neither desulfation method examined removed the sulfate groups from H2SO4-prepared CNWs completely. An estimation of surface sulfate esterification levels was made based on a model of the cellulose structure and available surface area of CNWs. According to these models, more than one third of hydroxyl groups on the surface were substituted by sulfate.
AB - Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, combustion gas analysis and N2 adsorption were used to quantify the degree of desulfation of cellulose nanowhiskers (CNWs). CNWs were produced by hydrolyzing cotton cellulose with sulfuric acid or hydrochloric acid. Hydrochloric acid treatment did not result in any cellulose chemical modification. Hydrolysis using H2SO4 introduced sulfate groups onto the cellulose surface. Our results indicate that commercial cotton cellulose as received contained sulfur. The sulfur content of H 2SO4-prepared CNWs was higher than that exhibited by the original cellulose due to the esterification process. Two desulfation methods, acid-catalyzed and solvolytic desulfation, have been explored to remove the sulfate groups. Neither desulfation method examined removed the sulfate groups from H2SO4-prepared CNWs completely. An estimation of surface sulfate esterification levels was made based on a model of the cellulose structure and available surface area of CNWs. According to these models, more than one third of hydroxyl groups on the surface were substituted by sulfate.
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U2 - 10.1016/j.carbpol.2012.10.078
DO - 10.1016/j.carbpol.2012.10.078
M3 - Article
C2 - 23399223
AN - SCOPUS:84873604166
SN - 0144-8617
VL - 92
SP - 1809
EP - 1816
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
IS - 2
ER -