New cellulose crystallinity estimation method that differentiates between organized and crystalline phases

Umesh P Agarwal; Sally A Ralph; Richard S Reiner; Carlos Baez

doi:10.1016/j.carbpol.2018.03.003

New cellulose crystallinity estimation method that differentiates between organized and crystalline phases

Carbohydr Polym. 2018 Jun 15:190:262-270. doi: 10.1016/j.carbpol.2018.03.003. Epub 2018 Mar 5.

Authors

Umesh P Agarwal¹, Sally A Ralph², Richard S Reiner², Carlos Baez²

Affiliations

¹ Fiber and Chemical Sciences Research, USDA FS, Forest Products Laboratory, 1 Gifford Pinchot Drive, Madison, WI, 53726-2398, United States. Electronic address: uagarwal@fs.fed.us.
² Fiber and Chemical Sciences Research, USDA FS, Forest Products Laboratory, 1 Gifford Pinchot Drive, Madison, WI, 53726-2398, United States.

PMID: 29628247
DOI: 10.1016/j.carbpol.2018.03.003

Abstract

A new method is proposed for estimation of cellulose crystallinity (CrI) based on 93 cm^-1 Raman band in spectra of cellulose I materials. In this method (93-Raman), CrI was determined based on regression that was developed using the ratios of peak-heights of the 93 and 1096 cm^-1 Raman bands (I₉₃/I₁₀₉₆). For calibration purposes, a set of eight samples, all derived from cotton microcrystalline cellulose Whatman CC31 were selected. When the peak intensity ratios (I₉₃/I₁₀₉₆) were plotted against the calculated CrIs of the calibration set samples, the plot showed an excellent linear correlation (R² = 0.9888). The 93-Raman method was used to estimate crystallinities of a number of cellulose materials including poplar wood samples that were hydrothermally treated at various temperatures. The wood 93-Raman CrI data showed that the method is able to differentiate between organized and crystalline phases of cellulose, a capability lacking in many other CrI estimation methods.

Keywords: Cellulose crystallinity; Crystalline; Hydrothermal; Low frequency; Organized; Raman spectroscopy; Wood.

Published by Elsevier Ltd.