Jürgen Sartori

Novel paper sizing agents from renewables. Part 3: Emulsion stability and hydrolysis behavior compared to conventional sizes

Abstract The hydrolytic stability and sizing behavior of a new paper sizing agent based on renewable vegetable oils (maleated sunflower oil, high oleic: MSOHO) was compared to two conventional alkenyl succinic anhydride (ASA) specimens, a commercial sample, and a reagent-grade ASA sample. At various pH conditions as well as upon addition of Ca2+ ions, MSOHO was more stable than both ASA samples. This superior stability of MSOHO was also supported by zeta potential measurements over 1 week. Whereas for sizing of paper higher dosages of MSOHO were needed to gain certain water repellency as compared to the ASA samples, the addition of alum had a pronounced positive effect on the sizing efficiency of MSOHO. The higher stability of MSOHO made it possible to size with an MSOHO-starch emulsion that was aged for one day at room temperature, when conventional ASA-starch emulsion had long lost any sizing efficiency.

Novel paper sizing agents from renewables. Part 1: Preparation of a paper sizing agent derived from natural plant oils

Abstract Natural oils derived from linseed, rapeseed, soybean, and a special breed of sunflower were tested for the production of maleated fatty oils for paper sizing in the ene-reaction with maleic anhydride. All these maleated oils were subjected to a conventional sizing test proving their ability to hydrophobize handsheets. Natural oils having only monounsaturated fatty acid residues (oleic acid) in the triglycerides worked best by having lower product viscosity and higher yields. The optimized production procedure employs antioxidant addition, an increased maleic anhydride:triglyceride ratio of 4:1, as well as increased pressure to reduce undesired polymeric byproducts and to increase yield.

Novel Paper Sizing Agents Based on Renewables. Part 6: Sizing Properties of Maleated High Oleic Sunflower Oil

Abstract The sizing efficiency of maleated high oleic sunflower oil (MSOHO), a green reactive sizing agent, was studied in various sizing tests. MSOHO can be applied in the papermaking process according to protocols that are commonly used for the currently popular alkenyl succinic anhydride (ASA) sizing. While an adequate degree of sizing was reached with pure MSOHO, blends of MSOHO and fatty acid anhydride (FAA), another green sizing agent, gave even better results, coming close to the efficiency of pure ASA. Although both pure sizing agents - FAA as well as MSOHO - lack some efficiency when compared to ASA, blending those two sizing agents at an optimum ratio closes this gap with respect to ASA. This synergism was not caused by simply decreasing the viscosity of MSOHO. Blends of ASA-MSOHO and ASA-MSOHO-FAA were proposed for full-scale mill trials.

Novel paper sizing agents based on renewables. Part 4: Application properties in comparison to conventional ASA sizes

Abstract Reactive paper sizing agents, such as alkenyl succinic anhydride (ASA), provide hydrophobicity to paper. The reactive anhydride group of these reagents is highly susceptible to reaction with water and thus resistance against hydrolysis is of primary importance for their practical application. This study describes different application-relevant properties of recently developed sizing agents that are based on renewable vegetable oils including hydrolysis behavior, time-dependent sizing efficiency, and tendency to form deposits or foam. The novel sizing agents – maleated high oleic sunflower oil (MSOHO) and maleated rapeseed oil (MRSO) – are compared to conventional ASA as the state-of-the-art sizing agent. Although the reactive group is the same in all reagents, there are pronounced differences between the three reagents, with MSOHO showing the best performance, i.e., the slowest hydrolysis. This oil has a higher ratio of hydrophobic side chains that impede the water attack at the anhydride group. Also, the higher viscosity of MSOHO plays an important role in performance, because diffusion of water molecules into a MSOHO emulsion droplet is much slower than in the case of conventional ASA.

Alkaline degradation of model compounds related to beech xylan

Abstract To address the chemical behavior of beech xylan (O-acetyl-4-O-methyl-glucuronoxylan) under alkaline conditions, three model compounds, 2-O-methylxylobiose (1), aldobiouronic acid (4-O-methyl-α-D-glucopyranosyluronic acid-(1→2)-xylose, 2), and aldotriouronic acid (4-Omethyl-α-D-glucopyranosyluronic acid-(1→2)-β-D-xylopyranosyl-(1→4)-D-xylose, 3), were subjected to strong alkaline conditions equal to those used for the industrial production of viscose (18% NaOH, 43°C). Kinetics of the degradation of the model compounds were monitored by capillary electrophoresis in combination with pre-column derivatization. It was demonstrated that substitution at O-2 of the reducing xylose unit strongly retarded the alkaline degradation reactions (1 and 2). By isotopic labeling experiments and isolation of degradation products it was shown that under the pertinent conditions deprotonation at C-2 occurs, followed by epimerization to the respective lyxo derivative. Aldotriouronic acid 3 was degraded to 2 as an intermediate according to classical peeling pathways. Genuine degradation reactions and epimerization processes were distinguished.

Novel paper sizing agents from renewables. Part 2: Characterization of maleated high oleic sunflower oil (MSOHO)

Abstract Maleated oils derived from high oleic sunflower oil (MSOHO) have promising applications in paper sizing as a green alternative to conventional reactive sizing agents, such as alkenyl succinic anhydride. In this study, MSOHO was comprehensively characterized analytically by attenuated total reflection infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy with full resonance assignment, and mass spectrometry.

Novel paper sizing agents based on renewables. Part 5: characterization of maleated oleates by ozonolysis

Abstract Maleated high oleic sunflower oil (maleated SOHO, MSOHO) is a promising substitute for alkenyl succinic anhydrides (ASA) that are widely used as sizing agents for paper. The part of the MSOHO molecule that is believed to be responsible for adhesion of the molecule onto cellulose, i.e., the maleated oleic acid moiety, was separately prepared and analytically characterized. Structural analysis was completed by studies of the molecular fragments obtained upon ozonolysis. The interesting question of whether there was a preferential reactivity during the ene-reaction of maleic anhydride with oleates was answered in a way that the newly formed double bond was placed to either side with no apparent selectivity.