Abstract
Viscosity measurement is a reasonable and useful routine
characterization and quality control measurement for
fibril cellulose production. The method is based on vane
geometry, which is widely accepted as a convenient way of
testing viscous, polydisperse materials. The method is
particularly advantageous for testing samples that are
significantly heterogeneous or that could slip when
tested with conventional, smooth spindle geometries such
as plate or coaxial cylinder. Viscosity describes a
suspension's internal resistance to flow. The higher the
fibrillation degree of the fibril cellulose, the more
internal friction is formed. In fibrillated celluloses,
the size, the aspect ratio and the amount of fibrils are
known to affect the viscosity. The routine viscosity
procedure includes specified rotational speeds of a
spindle from 0.5rpm to 100rpm. The apparent yield stress
can also be measured during the same measurement. The
measuring is performed for a sample volume of 250ml at a
controlled temperature of 20°C ± 1°C. The repeatability
of the Brookfield method is fairly good and the method
has been found to be suitable for charactetization of
various types of fibril cellulose samples. Because of
different nature of unmodified and chemically modified
fibril cellulose samples, the method has been fine-tuned
for these two sample categories. The viscosity
measurement described here has been unified within
several laboratories and the same measurement procedure
is now in routine use for characterization and quality
control of fibril cellulose. In the future,
commensurable characterization methods are needed in
order to compare results between different laboratories
worldwide. Based on these experiences we endeavour to get
this method for standardization.
| Original language | English |
|---|---|
| Title of host publication | International Conference on Nanotechnology 2013 |
| Publisher | TAPPI Press |
| Pages | 840-848 |
| ISBN (Print) | 978-1 -5108-1568-1 |
| Publication status | Published - 2013 |
| MoE publication type | A4 Article in a conference publication |
| Event | 2013 Tappi International Conference on Nanotechnology for Renewable Materials - Stockholm, Sweden Duration: 24 Jun 2013 → 27 Jun 2013 |
Conference
| Conference | 2013 Tappi International Conference on Nanotechnology for Renewable Materials |
|---|---|
| Country/Territory | Sweden |
| City | Stockholm |
| Period | 24/06/13 → 27/06/13 |
Keywords
- fibril cellulose
- characterization
- viscosity