New bio-based packaging materials are highly interesting for replacing conventional fossil based products for a more sustainable society. Waterstable cellulose fiber foams have been produced in a simple one-batch foam-forming process with drying under ambient conditions. The cellulose fiber foams have a low density (33-66 kg/m 3 ) and can inhibit microbial growth; two highly valuable features for insulating packaging materials, especially in combination with stability in water. Cationic chitosan and/or polyvinylamine have been added during the foamforming process to give the foams water-stability and antimicrobial properties. The structural and mechanical properties of the cellulose fiber foams have been studied and the antimicrobial properties have been evaluated with respect to both Escherichia coli, a common model bacteria and Aspergillus brasiliensis, a sporulating mold. The cellulose foams containing chitosan had both good water-stability and good antibacterial and antifungal properties, while the foams containing PVAm did disintegrate in water and did not inhibit fungal growth when nutrients were added to the foam, showing that it is possible to produce a bio-based foam material with the desired characters. This can be an interesting low-density packaging material for protection from both mechanical and microbial damage without using any toxic compounds.

Bacteria are removed from contaminated waters through adsorption onto the modified cellulose fiber surface in paper filters with pores larger than the bacteria.

The development of thermal insulation materials from sustainable, natural fibrous materials is desirable. In the present study, cellulose fiber based insulation foams made of bleached chemi thermo mechanical pulp (CTMP) have been investigated. To improve water resistance, the foams were impregnated with hydrophobic extractives from the outer bark of birch (Betula verrucosa) and dried. The surface morphology of the foams and the distribution of the deposited particles from the extractives were observed by scanning electron microscopy (SEM). The modified foams showed improved water resistance, as they did not disintegrate after immersion in water for 7 days, whereas the unmodified foam did. Compared to the unmodified foam, the modified foams absorbed 50% less moisture within 24 h. The modification had no negative effects on the thermal insulation properties, fungal resistance or compressive strength of the foams. The proposed approach is simple and can be easily integrated into plants working based on the biorefinery concept.

Portable purification systems are easy ways to obtain clean drinking water when there is no large-scale water treatment available. In this study, the potential to purify water using bacteria adsorbing cellulosic fibers, functionalized with polyelectrolytes according to the layer-by-layer method, is investigated. The adsorbed polyelectrolytes create a positive charge on the fiber surface that physically attracts and bonds with bacteria. Three types of cellulosic materials have been modified and tested for the bacterial removal capacity in water. The time, material-water ratio and bacterial concentration dependence, as well as the bacterial removal capacity in water from natural sources, have been evaluated. Freely dispersed bacteria adsorbing cellulosic fibers can remove greater than 99.9% of Escherichia coli from nonturbid water, with the most notable reduction occurring within the first hour. A filtering approach using modified cellulosic fibers is desirable for purification of natural water. An initial filtration test showed that polyelectrolyte multilayer modified cellulosic fibers can remove greater than 99% of bacteria from natural water. The bacteria adsorbing cellulosic fibers do not leach any biocides, and it is an environmentally sustainable and cheap option for disposable water purification devices.