Morphology of cellulose and oxidised cellulose in powder form

A series of 2,3-dialdehyde cellulose (DAC), sodium 2,3-dicarboxylate cellulose (NaDCC), and 2,3-dicarboxycellulose (DCC) (30,60,80, and 98% based on glucose monomer units) were prepared from commercial cellulose powder. The morphology of these powdered samples were investigated by scanning electron microscopy. The cellulose powder was found to be in the form of fibres having an aspect ratio of 14, and this value decreased for all the 30% oxidised derivatives, in agreement with wide-angle X-ray diffraction results (WAXRD). For DAC and NaDCC, the SEM of higher derivatives (60% oxidation and above) did not show presence of discrete fibres, but for all the DCC derivatives, the SEM showed discrete fibres. The surface effects seen in SEM are not apparent in WAXRD spectra, offering a new insight into the physical form of the oxidised cellulose samples. (C) 2002 Elsevier Science Ltd. All rights reserved.