Sorption of xylan onto softwood Kraft fibres

Purpose and goal

The overall objectives are to: -To increase the functionality of bleached softwood Kraft fibres with respect to fibre surface properties and the ability of softwood fibres to interact with paper additives. -To produce new bleached softwood Kraft pulps forming strong fibre networks in different fibre products. -To develop implementation-schemes of new technology regarding xylan sorption onto softwood fibres for industrial use.

Expected results and effects

The expected achievements and industrial relevance are: Design-data for a process for the production of improved and new functionalities of bleached softwood Kraft pulp/fibres is established. The properties and functionalities of the new fibres are evaluated under industrially relevant conditions.

Planned approach and implementation

Sub-project 0. Project co-ordination Sub-project 1. Activation of softwood fibres and xylan sorption The project will develop procedures to activate softwood pulps by application of upgraded and purified hardwood xylans to the fibre surface or by adsorption of modified xylan onto the fibre surface layer. The project will also establish the main mechanisms that link the properties of the xylans - surface xylans with the properties of the surface-activated softwood fibres. Activities: 1.1 Activation of softwood pulps by application of hardwood xylans; 1.2 Activation of Kraft fibres by application of chemically modified hemicelluloses. 1.3. Characterization of the properties of surface activated fibres and networks. Sub-project 2. Mill integration and product properties of xylan activated softwood fibres The surface-activated softwood fibres will be produced in laboratory trials under industrial-like conditions and evaluated in different applications in different fibre products. The laboratory studies will be carried out based on the results from Sub-project 1 and previous STFI-PF results. Mill trials evaluating the most interesting cases are planned. The project will demonstrate that surface xylan-activated softwood fibres exhibits the ability to interact more efficiently with papermaking additives, thus improving both the retention on the paper machine and the quality of the paper produced. Activities: 2.1 Process technologies of surface activated softwood fibres; 2.2 Product properties of surface activated softwood fibres; 2.3 Effect of xylan-lean black liquor on pulp properties.