Eero Hiltunen

Paper Technical Potential of Spruce SO2-Ethanol-Water (SEW) Pulp Compared to Kraft Pulp

Pulp mills will in the future no longer be only pulp production processes, but biorefineries, producing also green fuels and chemicals. In this context, the SO2-ethanol-water (SEW) process is highly interesting, as it enables better fractionation of the wood components in a biorefinery concept. However, the pulp produced must as well be competitive with the conventional pulps. In this study, the pulp properties of softwood SEW pulps were compared to kraft pulps. The SEW pulps possess good tensile, z-directional strength and higher brightness before bleaching. However, the limiting factors for SEW pulp utilization in conventional papermaking are low fibre strength, slow dewatering and high density. Nevertheless, these factors are not as crucial, for instance, in tissue production. Moreover, high density is even advantageous in specialty paper grades, while nanocellulose production would benefit from the decrease in beating energy consumption due to the low fibre strength and high fibre swelling.

Potential Use of Micro- and Nanofibrillated Cellulose Composites Exemplified by Paper

Naturally abundant, biodegradable, and sustainable plant and wood fibres are composed of smaller and progressively mechanically stronger entities. These smaller structural load-bearing cellulosic fibrils, termed as micro- and nanocellulosic fibrils, can be separated by defibrillating the pulp fibres with either mechanical, chemical, enzymatic, and ultrasound sonication methods or a combination of these treatments. Engineered biopolymer, like cellulosic fibrils, and inorganic mineral composite structures have the potential to create new material properties and applications. This chapter deals with the production, characterisation, and application of cellulosic fibril-precipitated calcium carbonate structures in printing and writing paper. We enunciate a novel composite paper consisting of cellulosic fibrils and precipitated calcium carbonate as the backbone structure and reinforced with a minimal fraction of long fibres. However, recent research investigations show that cellulosic fibrils and their composites find wide application across different fields of manufacturing such as polymers and plastics, medicine, construction, and automotive industries.