| 1. |
- Kisonen, Victor, et al.
(författare)
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Composite films of nanofibrillated cellulose and O-acetyl galactoglucomannan (GGM) coated with succinic esters of GGM showing potential as barrier material in food packaging
- 2015
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 50:8, s. 3189-3199
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Tidskriftsartikel (refereegranskat)abstract
- Nanofibrillated cellulose (NFC)-Norway spruce O-acetyl-galactoglucomannan (GGM) composite films were coated either with a novel succinic ester of GGM or with native GGM. NFC films were made for reference. The succinic ester of GGM was synthesised at low (GGM-Su1) and high (GGM-Su2) degree of substitution to obtain different level of water repellence. GGM and its succinic esters had good affinity with NFC substrate. This made it possible to implement the barrier functionality on the NFC network with the adequate mechanical properties. The coatings further enhanced the already excellent oxygen permeability properties, achieving 0.1 [(cm(3) A mu m)(m(2) kPa d)] as the lowest value with the NFC-GGM film double-coated with GGM-Su2. The films demonstrated pronounced stiffness by adding GGM to the NFC, as well as coating of GGM-Su2 on the NFC-GGM films at 0-90 % relative humidity. The films turned out to be impenetrable with grease even at high temperatures. NFC-GGM film with GGM-Su2 coating exhibited hydrophobic characteristics according to the water contact angle measurements. It was shown that adding 5.5 wt% of GGM to a NFC film and further 5.4 wt% of coating of GGM-Su or GGM on the film may highly enhance the feasibility of the biocomposites to be used for food packaging to replace typical oil-based non-biodegradable plastics currently used.
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| 2. |
- Rättö, Peter, et al.
(författare)
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Impact of different calendering strategies on barrier coating pick up
- 2023
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Ingår i: <em>TAPPICon 2023 - "Rock the Roll: Unleashing the Harmonies of the Paper Industry"</em>. - : TAPPI Press.
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Konferensbidrag (refereegranskat)abstract
- Paper was pre-calendered in a pilot scale configuration with a traditional soft nip calender and a metal belt calender. All calendering strategies reduced surface roughness and permeability of the samples, but different strategies affected the surface roughness and permeability differently. Six test points from the pilot calendered papers were chosen for laboratory coating studies. Uncalendered paper was included as reference samples. The calendered samples and the reference were pre-coated with a regular pigmented coating consisting of a GCC pigment and a SA latex. Both uncoated and pre-coated substates were barrier coated with a PVOH solution in one and two layers. The coating pick up was determined gravimetrically and the barrier properties were evaluated with TAPPI T454 grease resistance tests.
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| 3. |
- Rättö, Peter, et al.
(författare)
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Impact of different calendering strategies on barrier coating pickup
- 2023
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Ingår i: TAPPI Journal. - : TECH ASSOC PULP PAPER IND INC. - 0734-1415. ; 22:11, s. 665-673
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Tidskriftsartikel (refereegranskat)abstract
- Paper was pre-calendered in a pilot scale configuration with a traditional soft nip calender and a metal belt calender. All calendering strategies reduced surface roughness and permeability of the samples, but dif-ferent strategies affected the surface roughness and permeability differently. The metal belt calender seemed to have a larger effect on the large-scale variations compared to the soft nip calender.Six test points from the pilot calendered papers were chosen for laboratory coating studies. Uncalendered paper was included as reference samples. The calendered samples and the reference were pre-coated with a regular pig-mented coating consisting of a ground calcium carbonate (GCC) pigment and a styrene acrylate (SA) latex. Both uncoated and pre-coated substrates were barrier coated with a polyvinyl alcohol (PVOH) in one and two layers. The coating pickup was determined gravimetrically, and the barrier properties were evaluated with TAPPI Standard Test Method T 454 grease resistance test.All samples needed two PVOH coating layers to form a grease barrier. The uncalendered sheets showed the best results with one coating layer, but this was at the expense of a higher coating pickup compared to the calendered sheets. The barrier coating pickup could be reduced by a combination of high temperature metal belt calendering and pre-coating. The high temperature and long residence time in the nip enabled plasticization of the fibers. This led to an irreversible deformation, even after water application. This meant that the smoothness obtained during cal-endering would be less affected by water-induced roughening during the coating operation.Application: Most works on barrier research have previously focused on either coating formulations or coating processes. This work complements earlier research by demonstrating that the amount of required coating color can be reduced through an appropriate calendering strategy and use of pre-coating.
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| 4. |
- Valtakari, Dimitar, et al.
(författare)
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Planar fluidic channels on TiO2 nanoparticle coated paperboard
- 2016
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 31:2, s. 232-238
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Tidskriftsartikel (refereegranskat)abstract
- A new design for permanent, low-cost, and planar fluidic channels on TiO2 nanoparticle coated paperboard is demonstrated. Initially superhydrophobic TiO2 nanoparticle coatings can be converted to hydrophilic by ultraviolet (UVA) light, and fluidic channels can be generated. A simple water treatment after the UVA illumination converts the channels permanent when nanoparticles are removed from the illuminated and wetted areas as shown by water contact angle, FE-SEM, XPS, and ToF-SIMS analysis. This suggests new routes for inexpensive, easy to use point-of-care diagnostics based on planar fluidic channels.
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