Eye imaging technology provides opportunities in biotechnology
In his doctoral thesis, M.Sc. Sanna Haavisto, studied the flow properties of aqueous microcellulose suspensions. Optical coherence tomography, an imaging technology commonly used in medical eye imaging, was applied in a new way in his study. The measurement methods developed in the doctoral thesis can also be used to develop the material properties of microfibrillated celluloses, for example in textile innovations.
Microfibrillated cellulose is obtained by grinding cellulose fibres into a finely divided material of the micrometer range. An even finer material of microfibrillated cellulose is nanofibrillated cellulose. Thanks to various treatment techniques, micro and nanofibrillated cellulose can be transformed into materials that are very hard and flexible, transparent and translucent.
As potential ingredients for new biological materials and high-end products, micro and nanofibrillated celluloses are considered one of the most promising materials in the bio-economy. One of the applications awaiting a breakthrough is that of textile fibres, which are produced from these micro or nano-cellulosic materials. Currently, there are several textile innovations in Finland that are based on excellence in the pulp and paper industry.
In industrial scale applications, it is important to understand the properties of the material and the flow of the raw material. Aqueous suspensions of microfibrillated cellulose are very complex and, to date, particularly poorly known for their flow properties. According to Sanna Haavisto, this is due to the limited availability of appropriate measurement methods.
Measurement methods can also be used to develop the material properties of microfibrillated celluloses.
Haavisto's doctoral thesis shows how the fine structure of microfibrillated cellulose and its complex flow phenomena can be observed and measured. Optical coherence tomography is well suited to studying the flow properties of microfibrillated cellulose, even under conditions similar to those of industrial processing. According to Haavisto, the most important result of the doctoral thesis was the link between the boundary layer behaviour and the observed flow behaviour.
"Flow phenomena important for treatment occur in the immediate vicinity of the flow channel wall, i.e. in the boundary layer, which cannot be measured for microfibrillated cellulose by commonly used methods. Traditional measurement methods can even provide misleading information," explains Haavisto.
The measurement methods developed in the doctoral thesis can also be used to develop the material properties of microfibrillated celluloses. It should be noted that the method is not limited to the study of microcellulosic structures, but is applicable to a wide variety of materials.
