1. Rheological Properties of Highly Refined Cellulose:
Carboxymethylcellulose (CMC) Mixtures compared to
other commercially available Fibres.
Deepa Agarwal & Tim J. Foster
Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD,UK.
INTRODUCTION:
 Rheological properties are one of the key characteristics which influence a
wide range of commercial applications. E.g. food applications, cosmetics,
pharmaceuticals and paints & composites.
 These properties depend on the starting material and the process used to
make a product. One of such material is highly refined cellulose and this
poster investigate some aspects of its rheological properties.
OBJECTIVE:
This study focused on understanding the rheological properties of rehydrated
highly refined cellulose (HRC) (source: Spruce): carboxymethyl cellulose (CMC)
mixtures in comparison with other commercially available fibres like fruit fibres,
micro-crystalline cellulose (MCC) and bacterial cellulose.
METHODS & MATERIALS:
Materials: HRC (softwood: Spruce, never dried), HRC:CMC (Dry: flakes &
Powder) for comparison fruit fibers (CF-AQ, CF100, CF300), MCC, MCC+CMC and
bacterial cellulose were studied.
Analysis Methods: Oscillation (Amplitude & frequency sweeps) and Rotational
measurements were produced by using Anton Paar MCR - 301 Rheometer. Light
microscopy was performed by Olympus BX5 microscopy.
Graph 2: Complex Viscosity v/s Strain of various
cellulosic fibres at 1% w/w concentration.
Graph 1: Frequency sweeps of HRC and HRC:CMC 1%
w/w suspensions.
Similar viscoelastic behavior was observed with other cellulosic fibres. Both HRC & HRC:CMC suspensions showed very high
gel strength (complex viscosity) followed by bacterial cellulose (graph 2). It was also observed that HRC showed highest
elastic behavior whereas MCC showed least (graph 3). Finally, both fruit fibres and MCC suspensions show phase separation
compared all other materials (figure 2) which can be explained by the difference in network formation (graph 3).
Graph 3: 2D graph showing Tanδ at breakdown strain for
different cellulosic fibers.
CONCLUSIONS:
 Highly refined cellulose (HRC):Carboxyl methyl cellulose (CMC) suspensions are very stable and tends to shows gel-like
behaviors (G’>G”) with little dependency on frequency.
 Shear-thinning behavior with no sign of Thixotropy.
 Fruit Fibers i.e. CF-AQ+, CF100, MCC showed sign of phase separation .
 Viscosity trend: (Highest) HRC > Bacterial Cell > HRC:CMC > CFAQ+ > CF100>MCC:CMC (lowest).
References:
1. Henriksson, M., Henriksson, G., Berglund, L. A., & Lindstrom, T. (2007). An environmentally friendly method for enzyme-assisted preparation of
microfibrillated cellulose (MFC) nanofibers. European Polymer Journal, 43, (pp. 3434–3441).
2. Iotti M., Gregersen Ø. W., Moe S., Lenes M. (2011). Rheological studies of Microfibrillar cellulose water dispersions. J Polym Environ, 19, (pp. 137-145).
3. Copyright© The Benjamin/Cummings Publishing Co.,Inc,from Campbell’s Biology, 4th edition.
Acknowledgement: Sincere thanks Oslofjordfond, Norway for funding this study.
RESULTS & DISCUSSION:
Rheological properties showed that both HRC & HRC:CMC suspensions have gel-
like behavior (G’ > G”) at wide range of concentrations with little dependency on
frequency (graph 1). This can be explained by the network formed by
entanglement or intermolecular fibre-bonding of highly refined cellulose fibres
(HRC’s) in suspensions in comparison to other shorter fibres (figure 1).
Figure 2: 1% w/w water suspension of different cellulose fibres
comparison with HRC & HRC:CMC after 24hours of storage at room
temperature
CF100
HRC:CMC
Figure 1: Light microscopy
images of 1% w/w suspensions
with Congo-red dye.