| 1. |
- Cairns, Mathew J., et al.
(författare)
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Tetraethylorthosilicate-containing barrier dispersion coatings-Mechanism of action
- 2020
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Ingår i: Progress in organic coatings. - : Elsevier. - 0300-9440 .- 1873-331X. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the use of tetraethylorthosilicate (TEOS) as a silica precursor for water barrier poly(styrenebutadiene) latex dispersion coating applications. The TEOS is adsorbed at the surface interface by the latex particles in the aqueous dispersion due to the hydrophobic nature of the surface and the TEOS. It then undergoes hydrolysis and condensation to the silica phase in the interstitial sites in the partially dry close-packed polymer structure. The fully cured film exhibits a greater degree of coalescence than films prepared from the unmodified latex binder. Large discrete silica particles are not formed within the cured film; rather the films contain homogenous silica dispersion with a probable particle size no larger than 10 nm. This higher degree of coalescence results in improvements in water vapour barrier performance from 121 - 20 g m(-2) d(-1), with direct water barrier performance (Cobb 120 s) improving from 25 to < 2 g m(-2), compared to the silica-free film.
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| 2. |
- Hashemzehi, Mozhgan, et al.
(författare)
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A Comprehensive Review of Nanocellulose Modification and Applications in Papermaking and Packaging : Challenges, Technical Solutions, and Perspectives
- 2022
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Ingår i: BioResources. - : NC State University. - 1930-2126. ; 7:2, s. 3718-3780
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Tidskriftsartikel (refereegranskat)abstract
- The increasing usage of petroleum-based compounds has prompted numerous environmental concerns. Consequently, there has been a steady rise in research on the synthesis of useful materials from natural sources. Paper technologists are seeking environmentally acceptable dry end and wet end additives. Among the bio-based resources available, nanocellulose is a popular sustainable nanomaterial additive in the paper industry because of its high strength, high oxygen barrier performance, low density, great mechanical properties, and biocompatibility. NC’s extensive hydroxyl groups provide a unique possibility to dramatically modify the hydrophilicity and charge of the surface in order to improve their potential applications in the paper industry. The current paper reviews two series of surface modifications, each with various subcategories, depending on why modified nanocellulose is added in the paper production: to improve barrier properties or to improve mechanical properties of packaging materials. The methods presented in this study use the minimum amount of chemically hazardous solvents to have the least impact on the environment. This review focuses on modifications of nanocellulose and their subsequent application in the papermaking. The knowledge and the discussion presented in this review will form a literature source for future use by various stakeholders and the sustainable paper manufacturers.
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| 3. |
- Idris, Alamin, et al.
(författare)
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A review on predictive tortuosity models for composite films in gas barrier applications
- 2022
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Ingår i: JCT Research. - : Springer. - 1547-0091 .- 2168-8028. ; 19, s. 699-716
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Tidskriftsartikel (refereegranskat)abstract
- Different types of impermeable fillers are usually incorporated into polymeric coating film to enhance the gas barrier properties. For instance, impermeable fillers are commonly used in barrier coating due to their larger surface, which in turn serve as barrier inclusions restricting the penetrant gas to diffuse through a longer tortuous pathway. Modeling gas transport in barrier coating can help determine the shelf-life of packaged food and reduce product development resources and time. In this paper, related tortuosity-based models corresponding to different filler geometries are outlined. This review emphasizes the emerging trends in modeling the tortuous pathway and the respective relative permeability model to predict the gas barrier performance in composite films used for barrier coating applications. We review models incorporating a range of factors, including different shapes, geometries, angular orientations, alignments, randomness in distribution, stacking, interspacing, and the polydispersity of fillers. The approaches employed to develop the tortuosity-based phenomenological models starting with simplified filler geometry and orientations to more complex morphological features of the composite films are elaborated.
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| 4. |
- Idris, Alamin, et al.
(författare)
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Oxygen Barrier Performance of Poly (Vinyl Alcohol) Coating Films with Different Induced Crystallinity and Model Predictions
- 2021
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 11, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The presence of the crystalline regions in poly(vinyl alcohol) coating films acts as barrier clusters forcing the gas molecules to diffuse in a longer pathway in the amorphous region of the polymer, where diffusivity and solubility are promoted in comparison. Evaluating the influence of crystalline regions on the oxygen barrier property of a semi-crystalline polymer is thus essential to prepare better coating films. Poly(vinyl alcohol) coating films with varying induced crystallinity were prepared on a polyethylene terephthalate (PET) substrate by drying at different annealing temperatures for 10 min. The coating films were first delaminated from the PET substrate and then characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques to determine and confirm the induced percentage of crystallinity. The barrier performance of the coating films, i.e., the oxygen transmission rate (OTR), was measured at room temperature. Results showed a decrease in the OTR values of poly(vinyl alcohol) film with an increase in the degree of crystallinity of the polymer matrix. Tortuosity-based models, i.e., modified Nielsen models, were adopted to predict the barrier property of the semi-crystalline PVOH film with uniform or randomly distributed crystallites. A modified Nielsen model for orderly distributed crystallites with an aspect ratio of 3.4 and for randomly distributed crystallites with an aspect ratio of 10.4 resulted in a good correlation with the experimental observation. For the randomly distributed crystallites, lower absolute average relative errors of 4.66, 4.45, and 5.79% were observed as compared to orderly distributed crystallites when the degree of crystallinity was obtained using FTIR, DSC, and XRD data, respectively.
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| 5. |
- Martinez-Hermosilla, G. A., et al.
(författare)
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Relative permeability of barrier dispersion coatings applied on paper-based materials mathematical modeling and experimental validation : Mathematical modeling and experimental validation
- 2022
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Ingår i: JCT Research. - : Springer. - 1547-0091 .- 2168-8028. ; 19:2, s. 543-558
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Tidskriftsartikel (refereegranskat)abstract
- Barrier dispersion coatings have been used to improve barrier properties of paper-based materials. Like other technologies such as thermoplastic composites, dispersion coatings include fillers to create obstacles that complicate the pathways for permeants through coatings. The development of these technologies has received significant attention where even predictive barrier performance models have been created. However, to the best of our knowledge, none of them are applicable to barrier dispersion coatings. This research proposed a mathematical model to predict the relative permeability of barrier dispersion coatings applied on paper-based materials based on Fick’s law. The uncertainty of the barrier properties due to variation in filler orientation and spatial location was included through Monte Carlo simulation. Model validation against four models previously published by other authors, and water vapor transmission rate measured on three coating formations and two coating thicknesses was also conducted. The model predictions and experimental results showed that the increase in the amount of fillers reduces the relative permeability, and this reduction can be higher if the size of the fillers is larger. The predictions agreed with experimental results particularly at volume fractions below 10%. In most of the cases, the proposed model achieved better prediction in comparison with those already published. The model is useful to predict relative barrier performance of different coating formulations and can be used as a tool for future developments.
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| 6. |
- Mesic, Behudin (Beko), et al.
(författare)
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Hydrophobic clay in starch-based coatings
- 2011
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Ingår i: Appita journal. - 1038-6807. ; 64:2, s. 147-152
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate the mechanical and barrier properties of starch-based, low-weight coatings with a non-conventional hydrophobic clay tiller commonly used in plastic industry. A commercial linerboard was coated with two different types of potato starch- based coatings; one based on a conventional oxidized starch, while the other on a hydrophobic modified starch The coated linerboards were examined using scanning electron microscopy and characterised with respect to water absorption, water vapour transmission rate, glass transition temperature, tensile stiffness and wetting by water. The results obtained indicate that hydrophobically modified clay commonly used in the plastics industry may be used as a coating additive to improve liquid water and water vapour barrier properties of paper products.
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| 7. |
- Mesic, Behudin Beko, et al.
(författare)
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Latex-based barrier dispersion coating on linerboard : Flexographic multilayering versus single step conventional coating technology
- 2015
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 30:2, s. 349-359
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the possibility of using the flexographic printing process for the deposition of multilayered latex-based barrier dispersion coatings on linerboard to improve its moisture barrier properties. A coating formulation developed for a conventional coater has been tested using a flexographic printing web press. The performance of multi-layering of up to six layers was compared with a single step conventional coating process in terms of runnability and barrier performance. A commercial linerboard was used as substrate for both processes. The coated linerboard samples were examined using scanning electron microscopy and surface profiling, and were characterized with respect to their coating grammage, WVTR and water absorption (Cobb(120)) properties. The impact of waxes on water absorption was also investigated for the two coating strategies. The results show that for a similar total coating grammage ( about 6 g m(-2)), samples coated using the flexographic press showed better barrier performance and less cracks on the coated surfaces than samples coated using a conventional coating process.
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| 8. |
- Mesic, Beko, et al.
(författare)
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Effect of pressure and time on water absorption of coated paperboard based on a modified Cobb test method
- 2024
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Ingår i: TAPPI Journal. - : TAPPI Press. - 0734-1415. ; 23:4, s. 221-230
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Tidskriftsartikel (refereegranskat)abstract
- This manuscript presents the study of water absorption by paperboard subjected to water at high hydrostatic pressure based on a modified Cobb tester. The new tester is based on TAPPI Standard Test Method T 441; however, the water column can reach up to 550 mm. The evaluation consisted of measurements of water absorption for coated and uncoated paperboard at different exposure times from 5 s to 45 s and water column heights from 10 mm to 500 mm (corresponding to hydrostatic pressures 98 Pa and 4.9 kPa, respectively). The coatings were formulated as a combination of styrene acrylate (SA; two binder levels) and two types of ground calcium carbonates (differing particle sizes) to form the two pre -coating structures: open and closed. The coating weight was 6 g/m2 applied on 210 g/m2 solid bleached board (SBB). In addition, 210 g/m2 uncoated boards were studied. Characterization of the coatings was performed with scanning electron microscopy (SEM), mercury intrusion, and roughness. It was found that the new device properly mimics the conditions of the current Cobb tester. The characterization of the coating also confirmed the presence of more open/larger pores of open coatings, confirming the desired coating structure. The absorption of boards was mainly driven by exposure pressure by comparing with exposure time. This was already evident after shorter periods of exposure time at 5 s and also 15 s exposure time. Paperboards with open coatings showed slightly higher absorption than other boards.
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| 9. |
- Mesic, Beko, et al.
(författare)
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Film formation and barrier performance of latex based coating : Impact of drying temperature in a flexographic process
- 2019
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Ingår i: Progress in organic coatings. - : Elsevier. - 0300-9440 .- 1873-331X. ; 129, s. 43-51
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Tidskriftsartikel (refereegranskat)abstract
- The post-application behaviour of aqueous dispersion barrier coatings is investigated. We have adapted a dispersion formulation initially optimised for rod coating, for application to linerboard by a flexographic press. The clay/talc/wax/poly(styrene-butadiene) latex dispersion coatings demonstrated a 60% reduction in water vapour transport rate across the barrier, and a 75% reduction in direct water uptake when the applied film was dried at 75 degrees C. Multi-layer coatings with a combined application rate of 7 g m(-2) exhibited Cobb(120) direct water uptake of 16.3 +/- 3.7g m(-2) (120s water contact duration) and a water vapour transport rate of 140 +/- 12g m(-2) d(-1) (23 degrees C, 50% RH). Investigation of the post-coating curing regime demonstrated a decrease in the prevalence of crack defects within the cured film, and corresponding improvement in barrier properties when higher drying temperatures were employed. Dynamic mechanical analysis of the cured films indicated improvements in homogeneity and a greater extent of intermolecular interactions in the coating formulations cured at elevated temperatures.
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| 10. |
- Mesic, Beko, et al.
(författare)
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Flexographic multilayering of conventional latex-based dispersion coatings containing small dose of silica nanoparticles : Runnability on a pilot scale and barrier performance
- 2023
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Ingår i: TAPPICon 2023 - "Rock the Roll: Unleashing the Harmonies of the Paper Industry". - : TAPPI Press. - 9781713877707
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Konferensbidrag (refereegranskat)abstract
- Adding functionality to packaging materials is a key element to designing innovative packaging solutions. The ability to apply functional coatings to packaging materials is a key element to increasing their performance and creating innovative packaging solutions. Flexography, a cost-effective printing method commonly used to print information and graphics directly onto a wide variety of packaging substrates, show good potential for applying functional coatings. In this study, conventional clay-latex coating formulations containing approx. 1.3% silica nanoparticles was applied on a linerboard using a pilot flexographic printing web press. The performance of multilayered silica-based coatings was compared with conventional coatings containing talc and/or wax dispersion in terms of runnability and barrier performance. Coating grammage increased with increasing number of coating layers and a significant decrease in both the water vapor transport rate (WVTR) and the direct water uptake of water (Cobb120 wettability test) is observed for coatings containing silica particle. In general, silica-based coatings performed slightly better than talc-based coatings. Talc/wax-based coatings had the highest variation in surface roughness due to uneven distribution and variations of coating layers.
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