Ehrung für Dissertation
Die Dissertation von Frau DI Elisabeth Lackinger „Novel ASA substitutes in paper sizing based on renewable raw materials“, angefertigt im CD-Labor „Advanced cellulose chemistry and analytics“ (Betreuer: T. Rosenau / A. Potthast), wurde mit dem Förderpreis 2011 der Österreichischen Papierindustrie ausgezeichnet.
Sizing agents are used in paper production to improve the paper’s resistance against penetration of water and thus to increase its printability and durability. Nowadays, alkenyl succinic anhydride (ASA) is the most commonly used paper sizing agent, it is fully based on petrochemical resources (olefins). It was the goal of the PhD thesis to develop a sizing agent based on vegetable oil that can replace the petrochemical sources. In addition, the novel saying agent was supposed to be produced according to a facile in a one-step synthesis, to have good application characteristics, and to provide sufficient sizing to paper at low dosages. Furthermore the new sizing agent should possibly be more stable against hydrolysis than conventional ASA, thus minimizing deposit formation at paper machines, and should be economically feasible.
Relevant sizing characteristics including sizing efficiency, viscosity, composition of fatty acid residues on the triglycerides, formation of by-products, and yield were studied for maleated linseed, rapeseed, soybean, and high oleic sunflower oil. The most promising product – maleated high oleic sunflower oil (MSOHO) – was then comprehensively analytically characterized including attenuated total reflection infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and a combination of ozone cleavage and pyrolysis gas chromatography.
As one criterion for the applicability of sizing agents is their hydrolytic stability, several methods were used to monitor this feature for the new MSOHO product in comparison with the well-established ASA size. A higher hydrolytic stability of MSOHO, especially in the presence of calcium ions, was confirmed, which reduces the risk of deposit formation in the paper mill. Another focus of this thesis was to optimize MSOHO’s sizing characteristics towards high efficiency comparable to that of ASA. The influence of fillers and auxiliary (aluminum sulphate) addition was investigated as well. Furthermore blending MSOHO with fatty acid anhydride, another green sizing agent, was a suitable way to reduce the viscosity of the agent significantly, and to raise its efficiency toward ASA levels.
In summary, in the framework of the thesis, a novel sizing agent was developed (Maleinated Sunflower Oil, High-Oleic, MSOHO) which is purely based on renewable resources. The novel agent meets all the above requirements. It performs comparable to ASA – in some aspects even better – and is practically as well as economically feasible as ASA substitute in large-scale paper production.
Figure: Paper sizing with maleated vegetable oil, production of maleated vegetable oil (3): monomaleation of glycerin trioleate (1) with maleic anhydride (2).