| 1. |
- Lappalainen, Timo, et al.
(författare)
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Foam forming revisited. Part II. Effect of surfactant on the properties of foam-formed paper products
- 2014
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 29:4, s. 689-699
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Tidskriftsartikel (refereegranskat)abstract
- This article focuses on the properties of paper samples made using foam-laid technology. The effects of three surfactants, namely sodium dodecyl sulphate (SDS), sodium alkyl ether sulphate (SAES), and linear chain alkyl polyglucoside (C8/C10-Gluc), on properties of foam formed paper samples were studied, using chemithermo-mechanical (CTMP) spruce pulp and bleached kraft pulp. The results show that the type of surfactant used in foam forming has significant effects on the mechanical properties and quality of paper. In the presence of ionic polymers, the charge of surfactant has a significant effect on the formation of the paper sample. It was also shown that at AKD dosages ≥ 3 kg/t, the water absorbency of water formed paper samples was greater than that of foam-formed samples made using C8/C10-Gluc. Foam-forming also produced greater dryness after forming and wet-pressing than the water forming method. The type and dosage of surfactant had a significant impact on dewatering. Filler retention of foam-formed samples was significantly higher when using a non-ionic surfactant instead of an anionic surfactant. The effect of the strength additive (cationic starch) in increasing the strength of foam-formed samples was less in the presence of anionic surfactants than with non-ionic surfactants.
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| 2. |
- Mira, Isabel C., et al.
(författare)
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Foam forming revisited Part I. Foaming behaviour of fibre-surfactant systems
- 2014
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Ingår i: Nordic Pulp & Paper Research Journal. - : SPCI. - 0283-2631 .- 2000-0669. ; 29:4, s. 679-688
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Tidskriftsartikel (refereegranskat)abstract
- The foaming properties of typical chemithermo-mechanical (CTMP) and kraft pulp paper making formulations in the presence of a series of surfactants were investigated using a lab-scale foaming set up. Foamability, foam stability, and bubble size distribution of the generated foam-fibre systems were measured. The foaming behaviour of the fibre/surfactant systems was found to be dependent on the surfactant concentration. Foams fulfilling the target requirements of air content (ca. 65% v/v air) and average bubble size (25 to 75 μm in radius) were obtained with all the seven surfactants tested. Three of the surfactants were found to allow for a rapid foaming in the system, namely sodium dodecyl sulphate (SDS), a commercial mixture of alkyl and ethoxylated alkyl sulphates, (MixSAES) and a commercial mixture of short chain alkyl glucosides (C8/C10Gluc). The rapid foaming is believed to be an intrinsic property of mixtures of surfactants with the right molecular structures and in the right proportion with respect to each other. On the other hand, the minimum surfactant concentrations required to reach the target foam volumes were lowest for surfactants with an anionic character. Further, the type of pulp fibre and the presence of GCC in the surfactant/pulp formulation were found to have very little effect on the foaming performance of the suspensions.
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| 3. |
- Oksanen, Antti, et al.
(författare)
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Improving Wet Web Runnability and Paper Quality by an Uncharged Polysaccharide
- 2011
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Ingår i: J BIOBASED MATER BIO. - : American Scientific Publishers. - 1556-6560. ; 5:2, s. 187-191
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Tidskriftsartikel (refereegranskat)abstract
- The effects of xyloglucan addition on wet web strength, drying tension and end product quality of bleached birch kraft pulps were examined with laboratory trials. Specific xyloglucan dosages were applied onto wet fibre networks by spraying. Laboratory sheets were prepared of never-dried and once-dried birch pulps. Wet sheet strength and drying characteristics were analysed using diverse analytical instruments. Structural, strength and surface properties of dry sheet samples were tested according to standard methods. Wet web strength and tension holding potential of test samples increased with the addition of xyloglucan, which is an indication of better wet web runnability. Xyloglucan also increased the drying tension. Besides enhanced runnability, xyloglucan treatment was also found to improve end product quality by improving smoothness and dry strength properties, and decreasing air permeability. Results indicate that xyloglucan treatment has greater strengthening potential with once-dried chemical pulp, whereas the effect with never-dried pulp was smaller. Never-dried fibre has high natural bonding ability when once-dried fibres re-swelling and thus bonding ability has deteriorated in drying process. Therefore, xyloglucan seems to have potential especially in recovering the strength properties of pulp with hornified cell walls, such as in recycled pulp. In general, these results can be exploited in paper and board machines for tailoring fibre networks for different product grades or special functional products.
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| 4. |
- Salminen, Kristian, et al.
(författare)
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Foam forming-the effects of surfactant type on characteristics of fiber-foam suspension and properties of formed fiber network
- 2014
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Ingår i: Paper Conference and Trade Show, PaperCon 2014. - : TAPPI Press. - 9781510801288 ; , s. 758-765
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Konferensbidrag (refereegranskat)abstract
- The properties and behavior of pure aqueous foams have been quite extensively studied. On the other hand, very little is known about the chemical interactions between foaming agents and paper/board making raw materials in aqueous fiber-foam suspensions. The objective of this examination was to increase the understanding of basic mechanisms affecting fiber-foam suspension. In particular, gaining understanding of the chemical interactions between foaming agents and paper/board making raw materials was of great interest. The foaming behavior of pulp formulations in the presence of three anionic and four non-ionic foaming aids was tested with a tailor-made foaming test environment. Foaming aids for testing were chosen based on their reported good foaming properties, environmental safety, and availability as bulk chemicals, as well as their insensitivity to changes in temperature and pH within limits relevant to the foam forming process. Foam formed hand sheets with different furnish recipes were made and tested to evaluate the effect of the three selected foaming agents (selected based on their foaming characteristics) on the formation and retention processes, the technical properties of the hand sheets, and the performance of other chemicals used in paper/board manufacturing in the presence of the foaming aids. Additionally, the potential of utilizing the selected foaming aids in practical foam forming of paper or board was verified in a small-scale pilot trial. The results obtained in these laboratory and pilot-scale studies showed that the type and amount of foaming aids used have significant effects on foam properties, filler retention, sizing, dewatering, bulk, and mechanical properties of the fiber network. In fact, the selection of the foaming aid and its interaction with other wet end additives seems to be one of the key factors affecting the processability and quality of foam formed products.
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