Browsing by Author "Saastamoinen, Joni"
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Item Influence of the solute's molecular weight distribution on the spinnability of cellulose-ionic liquid solutions(Aalto University, 2011) Saastamoinen, Joni; Hummel, Michael; Lipponen, Sami; Biotekniikan ja kemian tekniikan laitos; Seppälä, JukkaThe main experimental objective of this thesis was to investigate the effect of cellulose's weight distribution on the dry-jet wet spinnability and shear rheological properties of cellulose-l-ethyl-3-methylimidazolium acetate (EMIMOAc) solution. Secondary object was to determine a relation between the spinnability and measured rheological properties of the spinnable solution. The objective of the literature part was to review the field of spinning of polymer solutions and melts in order to acquire knowledge about the theoretical perspective of the experimental objective. This review contains general information and qualitative theories (presented theories offer qualitative value) about the spinning process which could be elaborated on in order to improve future investigations in this field (e.g. which questions need to be answered). Different authors who have pursued investigations and theories in the field of spinning have different views about this topic. Because of the lack of empirical results of cellulosy-EMIMOAc solution spinning and universal theories about spinnability, quantitative expressions were not utilized in order to derive a connection between different steps of the experimental part. Derived relations were built on the order of magnitude ofdifferent parameters from MWD-, rheological and spinnability properties of the solutions which is rather qualitative approach to the main problem. For the experimental task four cellulose-EMIMOAc solutions of varying molar mass distribution were prepared for spinning trials keeping weight average molar mass of the cellulose constant. The spinnability of each solutioin was investigated by determining the maximum draw-ratios which still enable stable spinning of the solution without filament break-up. Each solution was characterized by frequency sweep with a rotational rheometer. A relation between the maximum draw-ratio and increased polydispersity index (PDI) was observed after the spinning trials with three different solutions. Although it is difficult to define the optimal spinning conditions for different test solutions, it could be concluded that the spinnability of a cellulose-EMIMOAc solution increases due to increased proportion of high molecular weight cellulose chains.Item Spontaanisti itsekorjautuvat materiaalit(2008) Saastamoinen, Joni; Turunen, Markus; Elektroniikan, tietoliikenteen ja automaation tiedekunta; Turunen, Markus
