We present a detailed study on the influence of sonication energy and surfactant type on the electrical conductivity of nanocellulose-carbon nanotube (NFC-CNT) nanocomposite films. The study was made using a minimum amount of processing steps, chemicals and materials, to optimize the conductivity properties of free-standing flexible nanocomposite films. In general, the NFC-CNT film preparation process is sensitive concerning the dispersing phase of CNTs into a solution with NFC. In our study, we used sonication to carry out the dispersing phase of processing in the presence of surfactant. In the final phase, the films were prepared from the dispersion using centrifugal cast molding. The solid films were analyzed regarding their electrical conductivity using a four-probe measuring technique. We also characterized how conductivity properties were enhanced when surfactant was removed from nanocomposite films; to our knowledge this has not been reported previously. The results of our study indicated that the optimization of the surfactant type clearly affected the formation of freestanding films. The effect of sonication energy was significant in terms of conductivity. Using a relatively low 16 wt. % concentration of multiwall carbon nanotubes we achieved the highest conductivity value of 8.4 S/cm for nanocellulose-CNT films ever published in the current literature. This was achieved by optimizing the surfactant type and sonication energy per dry mass. Additionally, to further increase the conductivity, we defined a preparation step to remove the used surfactant from the final nanocomposite structure.

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The demand for biobased barrier packaging alternatives is constantly growing. Poly(lactic acid) (PLA)-based polymers are one of the most extensively studied biomass-derived synthetic polymers; however, they typically lack water-barrier properties. We synthesized a copolymer of D,L-lactic acid, 1,4-butanediol, and itaconic acid [poly(D,L-lactic acid-1,4-butanediol-itaconic acid) (PLAB-DIA)] via bulk polycondensation. The radical crosslinking reactions of the synthesized polymer were investigated with bulk crosslinking trials to find a formulation that was suitable for a rapidly crosslinkable barrier coating. The crosslinking efficiency was tested with methacrylate and acrylate crosslinkers together with peroxide radical initiators. Poly(ethylene glycol) diacrylate (numberaverage molecular weight 5 250 g/mol) together with dilauroyl peroxide proved to be the best crosslinker-initiator combination. An aqueous dispersion of PLABDIA was prepared with a thermomechanical method and applied to commercial boxboard on a pilotscale line coater. With a coating weight of 10 g/m 2 , a water vapor transmission rate of 22.8 g/m 2 d was achieved, and this coating outperformed commercial extruded PLA coatings. The samples also showed very good grease resistance and would, therefore, be a good solution for the packaging of dry and fatty goods.

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.