Graphite materials show high electrical and thermal conductivity making them useful in electronics both as electrical conductor, but as of today primarily used as a thermal conductor for thermal management and as the dominating anode material in lithium ion batteries. The conductivities depend on for example the degree of graphitisation, that is how close the material is to perfect graphite. Graphite materials can occur naturally in the earth’s bedrock and can thus be extracted by mining and is then called natural graphite. Graphitic carbon materials can also be synthesised and are then usually referred to a synthetic or artificial graphite, even though they should be referred to as graphite materials if being strict, as they never reach the structure of perfect graphite and always contain some defects and irregularities. This report starts with a short description of all carbon allotropes, i.e. structurally different forms of the same element due to how the atoms are chemically bonded to each other. It then continues with an overview of how graphitic carbon materials can and should be characterised, as well as analytical methods for making this characterisation. After this a section on production methods for graphite materials follows, that dependent on the principles they operate by are divided into: • Mining for graphite that occurs naturally in the earth’s bedrock. • High temperature heat-treatment, so called carbonisation, hydrothermal carbonisation if done in water, and graphitisation. • Chemical vapour deposition, i.e. depositing molecules or atoms in gas phase on a solid surface, that is used to synthesise pyrolytic carbon and graphite. • Extraction from a steelmaking by-product called Kish to obtain so called Kish graphite. • Thermal decomposition of carbides. This is followed by a section on the today most common and important graphite materials, which are: natural graphite (mined), anisotropic synthetic graphite, isotropic synthetic graphite, pyrolytic carbon and graphite. This section also includes specific production process details for the above listed graphite materials, their main properties, advantages, and common uses. Two of the most common and important uses of graphite materials, i.e. as anode in lithium ion batteries and for thermal management in electronics, are described somewhat more in depth. The focus of this report is biomass derived graphitic materials and this focus start fully first in section number four, which compares published values on electrical and thermal conductivity of different fossil and bio-based graphitic carbon materials. This comparison clearly shows that it is very challenging to derive graphitic carbon materials with high conductivities from biomass. This is because essentially all biomass is so-called non-graphitising or hard carbon precursor meaning that it is not transformed into highly graphitic carbon no matter how high temperature it is heated to. Catalytic graphitisation using metals salts or oxides can increase the degree of graphitisation that can be achieved, but all substances used for catalysing graphitisation forms solid nanoparticles which leaves voids when removed by for example acid dissolution, making the resulting graphitic material porous which in turn limits its electrical and thermal conductivity. Of all production processes reviewed here to create highly electrically and thermally conductive graphitic carbon materials from biomass, requiring a high degree of graphitisation and dense material, two methods stand out as especially interesting: • Chemical vapour deposition on suitable substrate (carbon materials, metals or ceramics) using biomass as carbon source. • Resistive heating of biomass derived films/objects. Bio-based free-standing graphene film with very high electrical and thermal conductivity have been produced using chemical vapour deposition technique. From a practical handling perspective, it would be beneficial to create thicker highly graphitic carbon films to make them stronger, although it may reduce the conductivities of the material. Methods based on chemical vapour deposition may be improved to be able to produce thicker graphitic films. Resistive heating of a film made of e.g. biobased lignin, mixed with mined graphene to 2192 °C have been shown to create a highly graphitic carbon film with the excellent electrical conductivity of 4480 S/cm. By substituting the mined graphene to bio-based ditto may open up for the production of a fully biobased, highly graphitic film with excellent conductive properties. It is suggested that the way to achieve fully biobased highly graphitic and dense films is to further refine the chemical vapour deposition and the resistive heating method.

In this study, the addition of up to four layers of PEM was studied and compared with the use of single-additions or dual-additions of the same chemicals with respect to their effect on strength and bulk properties of paper sheets produced in the laboratory. First, this was made under clean conditions, i.e. in tap water, to set a baseline for the performance. The systems studied were cationic/anionic polyacrylamide (CPAM/APAM), polyvinylamine/carboxymethyl cellulose (PVAm/CMC) and cationic starch/anionic polyacrylamide (CS/APAM).One of the main findings of the study was that with single-additions with increasing dosage levels of PVAm, CPAM or CS, the tensile strength index of the produced sheets increased at first, but the effect seemed to level off at higher dosages. By comparing the effect from single-addition of each cationic component to the effect of a polyelectrolyte multilayer (1-4 layers) of the same component together with an anionic component, it was found that significantly higher tensile strength could be reached with the PEM strategy for the combinations PVAm/CMC and CS/APAM. For CPAM/APAM, however, very little advantage of using a multilayering approach was seen.All measured variations in sheet density were small, although with some indications that the density was lower for sheets with PEM, medium for sheets made with a single-dosage strategy and highest for sheets made with the dual-addition strategies.The later part of this activity also addressed the influence from dissolved and colloidal substances (DCS) to investigate the possibilities of implementing the polyelectrolyte multilayering technique in practice by repeating some of the trial points of the CS/APAM system in mill process water. Firstly, this part of the study showed that PEMs can be successfully built in mill process waters. Further, it was found that although the adsorbed amounts might differ compared to in the cleaner system, the trends for the dosage strategies and their strengthening effects remained.

This is the final report for the Innventia/RISE Bioeconomy research programme area “Source-Efficient Paper and Board Making”, which was executed 2015-2017.The overall aim of the Source Efficient Paper and Board Making was to improve the resource efficiency in paper and board production. This was achieved by combining paper chemistry, paper physics and process technology. A particular goal was to reduce raw material consumption through the use of stronger materials or creation of bulk, which are needed to maintain bending stiffness and mechanical properties if the grammage is reduced. The work in the project has been carried out in laboratory scale and in pilot scale using the FEX pilot paper machine and the dynamic flow loop.

Previous research made at RISE Bioeconomy (former Innventia) has shown significant improvements to both retention and formation when retention AIDS, cationic polyacrylamide (C-PAM) and microparticulate silica, were added very close to the headbox given that the mixing was adequate. The pilot trial that showed these results used a somewhat idealised system since the furnish used consisted solely of fibre, filler and retention aid. In addition to these components, it is very common to add some cationic starch to the thick stock to increase the paper strength. When cationic starch (0.5%) had been added to the thick stock there was no longer any obvious positive effect on the retention-formation relationship with the late dosage of the retention system. This spurred a further investigation and trials in which also the cationic starch was added just prior to the headbox, such that the contact times of all three components (C-PAM, microparticulate silica and cationic starch) were less than 3 seconds prior to forming. Also in these cases, the general positive effect on the formation-retention relationship was not seen, but the C-PAM dosage needed to obtain a certain retention level was much less as compared to when the normal dosage positions were used. This clearly demonstrates possibilities to drastically decrease the C-PAM consumption. Only marginal negative effect on the mechanical properties of the produced paper was seen when the starch was added just prior to the headbox as compared to in the thick stock. It is common wisdom that starch should have a long contact time to give optimal strength gain. The presented results show that this needs not to be the case, and the key is probably adequate mixing.

The economic potential in terms of variable cost needed for production of fine paper has been evaluated for a case where microfibrillated cellulose (MFC) was added in order to increase the filler content at maintained grammage and tensile index. MFC production was based on a mechanical enzymatic pretreatment procedure prior to high-pressure homogenisation. Two different scenarios were studied: without and with wet end starch. For cost evaluation, it was assumed that the cost for production MFC had been calculated from the pulp and enzyme price and energy needed for refining and homogenisation. Although the pulp used was a never-dried bleached softwood sulphite pulp, the price was assumed to be equal to that for bleached kraft pulp. Techno-economic analysis was based on a pilot scale trial using a mobile demonstration plant with a capacity to produce 100kg MFC. The plant consisted of a three-stage process: enzyme treatment, refining and homogenisation. It has been concluded that the use of MFC as a strength additive had a positive impact on the variable costs for a fine paper case when increasing the filler content.