TEMPO-mediated oxidation of oat β-d-glucan and its influences on paper properties
Introduction
Bonding between cellulosic fibers is known to play a critical role in meeting the strength requirements of paper products (Page, 1969). Though the strength of paper also depends on the strength of the component fibers, the inter-fiber bonds frequently can be considered as the “weak link” in a paper structure (Helle, 1963, Howard and Jowsey, 1989). Kraft pulp fibers suffer a reduction in their bonding ability when they are recycled (Weise and Paulapuro, 1996, Hubbe et al., 2007). Further demands are placed on paper's inter-fiber bonding ability due to increasing levels of mineral fillers (Shen, Song, Qian, & Liu, 2009), and also a gradual trend toward reduction in the mass per unit area of various paper and paperboard products (Nahrath, 2004, Kerman et al., 2009, Li et al., 2012).
It is well known that paper's inter-fiber bonding strength can be increased by addition of certain water-soluble polyelectrolytes such as cationic starch or acrylamide copolymers; these products are added as solutions to the fibrous slurry before formation of the sheet (Hubbe, 2006). It has been shown that related beneficial effects can be achieved by the addition of hemicellulose products as dry-strength agents (Denis et al., 2003, Suurnäkki et al., 2003, Bai et al., 2012). Hemicelluloses serve as a natural bonding agent when they are a component in ordinary kraft pulp fibers. Thus, it has been shown that excessive removal of hemicellulose, as in the case of overly aggressive “pre-extraction” treatments, can lead to paper that exhibits relatively low inter-fiber bond strength (Oksanen et al., 1997, Al-Dajani and Tschirner, 2008, Yoon and Van Heiningen, 2008).
Another approach that can be used to enhance the strength of paper is chemical modification. It has been shown, for example, that the dry strength properties of paper can be enhanced by TEMPO-mediated oxidation of bleached hardwood kraft fibers (Song & Law, 2010). The treatment was found to benefit not only the strength of paper made from never-dried fibers, but it also had a beneficial effect on recycled paper made from the same fibers. Best results were obtained when the oxidation of the fiber surfaces was carried out before the initial drying of the fibers.
The present work concerns the possible usage of a bonding agent prepared from a hemicellulose-rich byproduct of oat processing, a β-d-glucan product. The authors surmised that a more effective dry-strength additive could be prepared from a commercially available β-d-glucan-rich product by subjecting it to TEMPO-mediated oxidation (Isogai & Kato, 1998). In other words, the natural polysaccharide product was subjected to a form of oxidation that mainly affects the C6 position on the accessible glucopyranose units of the polysaccharide, leaving the polyelectrolyte chains and other OH groups largely unaffected. The increased anionic charge of the treated β-d-glucan product was intended to allow the material to be dissolved more readily in water, which is one criterion for selection of promising candidate materials to be evaluated as dry-strength agents (Hubbe, 2006). The additional negatively charged carboxylate groups also provide more handles by which the polyelectrolytes later can be retained during the papermaking process (Linke, 1968). The described approach was used for the first time as a strengthening system for papermaking.
Section snippets
Materials
Oat β-d-glucan was obtained from the Biovelop Company, Kimstad, Sweden. The molecular weight of the β-d-glucan was 1,300,000 Da. The compositional data were as follows: 32–35% of dietary fiber (soluble β-d-glucan), 34–37% of total dietary fiber, 54–56% of carbohydrate (maltodextrin), 2.5–3.5% of protein, 3–4% of ash, and 0.5–1% of fat. Kraft pulp of loblolly pine was prepared under the following laboratory conditions: liquor ratio 1:4.5, alkali dosage 19%, sulfidity 25%, and an H-Factor of 180.
Molecular weight of oxidized β-d-glucan
The viscosity data for the oxidized oat β-d-glucan are presented in Table 1. As shown, the viscosity values were decreased by 8.7%, 42.4%, and 64.4%, respectively, compared with the original β-d-glucan after thermal treatment, oxidation treatment (30 min), and alkali treatment. The decreases in viscosity values for oxidized oat β-d-glucan increased with increasing time of oxidation. These results indicate that the conditions of thermal treatment, oxidation, and alkali treatment were sufficient
Conclusions
The following main conclusions may be drawn from this study:
- 1.
Oxidized β-d-glucan prepared by TEMPO-mediated oxidation was effective in improving paper physical properties. Tensile index and folding endurance were increased by 36.0% and 125.4%, respectively, when the oxidized time was 30 min. Oxidation was confirmed by FTIR and elemental analyses.
- 2.
The dosage of oxidized β-d-glucan played the most important role in papermaking. Tensile index, burst index, and folding endurance of handsheets
Acknowledgements
Dr. Xianliang Song was supported in this work by Beijing Forestry University and China Scholarship Council. The authors also thank North Carolina State University for providing laboratory facilities for much of the described research.
References (29)
- et al.
Extraction and characterization of β-d-glucan from oat for industrial utilization
International Journal of Biological Macromolecules
(2010) - et al.
Influences of configuration and molecular weight of hemicelluloses on their paper-strengthening effects
Carbohydrate Polymers
(2012) - et al.
Acetylation of wheat straw hemicelluloses in N,N-dimethylacetamide/LiCl solvent system
Industrial Crops and Products
(1999) - et al.
Acetylation and characterization of spruce (Picea abies) galactoglucomannans
Carbohydrate Research
(2010) - et al.
Pre-extraction of hemicelluloses and subsequent kraft pulping: Part 1: Alkaline extraction
TAPPI Journal
(2008) Bonding of cellulose surfaces
- et al.
Seed storage hemicelluloses as wet-end additives in papermaking
Carbohydrate Polymers
(2003) Some aspects of fibre strength and fibre bondings in sulphate and sulphite paper
Svensk Papperstidning
(1963)- et al.
Effect of cationic starch on the tensile strength of paper
Journal of Pulp and Paper Science
(1989) - et al.
What happens to cellulosic fibers during papermaking and recycling? A review
Bioresources
(2007)
Bonding between cellulosic fibers in the absence and presence of dry-strength agents – A review
Bioresources
Preparation of polyuronic acid from cellulose by TEMPO-mediated oxidation
Cellulose
Structural analysis of water-soluble and -insoluble beta-glucans of whole-grain oats and barley
Carbohydrate Polymers
First operational experience with the high efficiency synthetic dry strength agents
Wochenblatt für Papierfabrikation
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