Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature. From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation. In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation. In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities. The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.

This thesis deals with processing of nanocellulose originating from pulps, with focus on mechanical pulp fibres and fines fractions. The nanocellulose materials produced within this research project were tested for different purposes ranging from strength additives in paper and paperboard products, via composite films to foam materials. TAPPI (Technical Association of Pulp &amp; Paper Industry) has recently suggested a standard terminology and nomenclature for nanocellulose materials (see paper I). In spite of that we have decided to use the terms nano-ligno-cellulose (NLC), microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and nanocellulose (NC) in this thesis . It is well-known that mainly chemical pulps are used as starting material in nanocellulose production. However, chemical pulps as bleached sulphite and bleached kraft are quite expensive. One more cost-effective alternative can be to use fibres or fines fractions from thermo-mechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP).   In paper II-IV, fractionation has been used to obtain fines fractions that can easily be mechanically treated using homogenisation. The idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nanocellulose. The integration of a nanocellulose unit process in a high-yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and paperboard grades.   Paper III describes how to utilise the crill measurement technique as a tool for qualitative estimation of the amount of micro- and nano-material produced in a certain process. The crill values of TMP- and CTMP-based nanocelluloses were measured as a function of the homogenisation time. Results showed that the crill values of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. In Paper V pretreating methods, hydrogen peroxide and TEMPO are evaluated. Crill measurement showed that hydrogen peroxide pretreatment (1% and 4%) and mechanical treatment time did not improve fibrillation efficiency as much as expected. However, for TEMPO-oxidised nanocelluloses, the crill value significantly increased with both the TEMPO chemical treatment and mechanical treatment time. In paper V-VII TEMPO-mediated oxidation systems (TEMPO/NaBr/NaClO) are applied to these fibres (CTMP and Sulphite pulp) in order to swell them so that it becomes easy to disrupt the fibres into nanofibres with mechanical treatment.   The demand for paperboard and other packaging materials are steadily increasing. Paper strength properties are crucial when the paperboard is to withstand high load. A solution that are investigated in papers IV and VI, is to use MFC as an alternative paper strength additive in papermaking. However, if one wish to target extremely higher strength improvement results, particularly for packaging paperboards, then it would be fair to use MFC or cationic starch (CS). In paper VI CS or TEMPO-based MFC was used to improve the strength properties of CTMP-based paperboard products. Results here indicate significant strength improvement with the use of different levels of CS (i.e., 20 and 10 kg t–1) and 5% MFC. The strengthening impact of 5% MFC was approximately equal to that of 10 kg t–1 of CS.   In paper VII, NFC and nanographite (NG) was used when producing composite films with enhanced sheet-resistance and mechanical properties. The films produced being quite stable, flexible, and bendable. Realising this concept of NFC-NG composite film would create new possibilities for technological advancement in the area of high-yield pulp technology.  Finally, in paper VIII, a new processing method for nanocellulose is introduced  where an organic acid (i.e., formic acid) is used. This eco-friendly approach has shown to be successful, a nanocellulose with a uniform size distribution has been produced. / <p>Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 och 7 inskickade, delarbete 6 och 8 manuskript.</p><p>At the time of the doctoral defence the following papers were unpublished: paper 5 and 7 submitted, paper 6 and 8 manuscripts.</p>

In this report, the washing efficiency of chemi-thermomechanical pulp (CTMP) from Norway spruce (Picea abies) was investigated when adjusting the temperature and pH during washing as well as implementing different number of wash steps. Concurrent effects of having a high pH and temperature were also examined. CTMP pulp has many uses, one of which is for the manufacturing of packaging board. Lately, this end product has seen a precipitous increase due to the increasing demand of an environmentally friendly alternative within the food packaging sector. A notorious problem associated with all mechanical pulps is how extractives are to a large extent still present after the pulping process, especially unsaturated lipids which are subject to oxidation. This results in the formation of odorous aldehydes that can be easily transferred into the food product, thus contaminating it by altering the perception of taste and odor. This is a frequent problem faced by the status quo liquid board industry. Washing is thus employed late downstream to lower the final wood resin content. Here, available literature has been collated for some basic introductory subjects such as softwood anatomy, wood resin and structures. All of this is described with a focus on softwood, leading up to a thorough breakdown of P. abies. Mechanical pulping and relevant deresination methods for CTMP production are also described, including washing. The objective of this thesis is to evaluate the trends of the final resin concentration as the chosen parameters are altered during washing. The pulp was provided by Rottneros Mill and their industrial process was simulated by using a Büchner funnel for washing. A Soxhlet extractor was used for determining the final extractive contents. It was found that the implementation of additional wash steps reduced the final resin content (1–4 wash steps). The same was found with increasing temperature (60, 70, 80 and 90 °C). The implementation of a fourth wash step seemed to be more efficient at higher temperatures. No conclusions could be drawn from altering the pH due to scattered data points with high uncertainties (pH 7, 8 and 9). The results are limited in terms of significance and are also subject to bias. / I denna rapport undersöktes tvätteffektiviteten av kemitermomekanisk massa (CTMP, chemi-thermomechanical pulp) tillverkad från gran (Picea abies) och hur den påverkas vid justeringar av temperatur, pH och antal tvättsteg. Ytterligare undersöktes förekomsten av eventuella samverkande effekter vid högre temperatur och pH. CTMP-massa har många användningsområden, däribland vid produktion av vätskekartong. På sistone har efterfrågan av vätskekartong ökat markant som ett svar på en allt större strävan efter ett mer miljövänligt alternativ inom matförpackningssektorn. Ett välkänt problem associerat med mekanisk massatillverkning är den stora mängden exktraktivämnen som kvarhålls i den färdiga massan. En viss del av dessa extraktivämnen utgörs av fleromättade fetter vilket är benägna att genomgå oxidation. Detta leder i sin tur till bildandet av flyktiga aldehyder som kan föras vidare till matprodukten och ge dem förändrad smak och lukt; ett problem som dagens vätskekartongproducenter står inför. Tillgänglig litteratur har sammanställts, där en inledande teoridel beskriver koncept såsom anatomi, strukturer och extraktivämnen hos barrved. Teoridelen övergår därefter till att ge en mer detaljerad beskrivning av P. abies och dess extraktivinnehåll. Ytterligare beskrivs mekanisk massatillverkning över lag och metoder för att eliminera extraktivämnen under produktionen av CTMP-massa (inklusive tvättning). Syftet med detta examensarbete är att utvärdera de trender i den slutliga extraktivhalten då de valda parametrarna justeras under tvättning. Massan tillhandahölls av Rottneros Bruk och deras tvättningsprocess simulerades med hjälp av en Büchner-tratt. En Soxhlet-extraktor användes för att utvärdera den slutliga extraktivhalten. Det visade sig att vid varje insättning av ett ytterligare tvättsteg (1–4 tvättsteg) gav en lägre extraktivhalt hos CTMP-massan. Desamma gällde vid ökande temperatur (60, 70, 80 and 90 °C). Implementering av ett fjärde tvättsteg tycks vara mer effektivt vid högre temperaturer. Det kunde dock inte dras några slutsatser huruvida pH påverkade tvättningen då dessa mätvärden fick stor spridning med höga osäkerheter (pH 7, 8 och 9). Resultaten besitter begränsad signifikans och kan även ha blivit utsatta för bias.