A single biopolymer film rarely has a competitive edge against synthetic films. One solution is to combine several layers with different properties into multilayer structures. In this way, for example, the barrier properties of bio‐based materials can be improved. In this study, the multilayer films are produced by combining three different techniques/materials: 1) dispersion coating (cellulose nanofibrils, CNF), 2) atomic layer deposition (Al2O3; aluminum oxide), and 3) extrusion coating (polyglycolic acid, PGA). Especially the CNF and PGA‐containing multilayer films show promising oxygen barrier improvements at different humidities. Thin inorganic coatings are brittle and sensitive toward stresses during converting, which may limit their use in such specific multilayer structures. The developed bio‐based films largely fulfill the barrier requirements of fresh food packaging. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42260.

The aim of this study was to evaluate a thin, TEMPO‐oxidized (2,2,6,6‐tetramethylpiperidine‐1‐oxyl–mediated oxidation) cellulose nanofibril (CNF) coating as a barrier layer in multilayer packaging films together with biobased polyethylenes. The purpose was also to explore the possible interactions between food products and the biobased films, and to evaluate the feasibility of these films for packaging of dry foods. CNF provided the biobased multilayer films with an oxygen barrier suitable for both demanding food products and modified atmosphere packaging (MAP). The MAP pouches made of these multilayer films retained their atmosphere and shape and protected ground hazelnuts from further oxidation for the storage time used in this study. However, irradiation used to sterilize packed foods and aroma compounds from clove in particular impaired the oxygen barrier property of the CNF layer, while the water vapor barrier property of the multilayer films remained unaffected. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44830.

No abstract

We report fully-printed top-gate-bottom-contact organic thin-film transistors using substrates prepared from cellulose nanofibers and commercially available printing inks to fabricate the devices. Gravure printing was used to coat the substrate with a polymer resist to decrease the surface roughness and close the surface. Transistor structures were fabricated using inkjet printing for conductors and gravure printing for the dielectric and semiconducting layers. The obtained transistor performance is compared to that of similar transistors on plastic substrate.

A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1) drying on a hot metal surface; (2) air impingement drying; and (3) hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature.