Fossil-based polymers dominate the packaging industry thanks to their performance and low cost. However, their negative impact on the biosphere demands a paradigm shift in the industry. Nature may provide an alternative in the form of suberin. Suberin is an amorphous polyester present in plants, where it contributes to controlling the water and gas exchange with the environment. The bark is rich in suberin, and it represents a large byproduct of the forestry industry; hence, it is a potential source of renewable monomers for the synthesis of packaging materials. In this study, we demonstrated that unrefined suberin monomers, extracted from birch bark, could be exploited to synthesize a cross-linked polyester film through a standard melt polycondensation and compression molding process. The polyester film resulted in being translucent while blocking UV radiation and having an elastomer-like behavior. The average measured water vapor transmission rate of 2660 g mu m day-1 m-2 was comparable to other polyesters, such as polylactide (1500-2000 g mu m day-1 m-2) and polycaprolactone (2653 g mu m day-1 m-2) at 23 +/- 2 degrees C, with an imposed gradient of 0-50% relative humidity. Finally, the thermal gravimetric analysis showed the absence of any unreacted suberin monomers, and although specific migration tests are required, these suberin-reconstructed polyester films are potential candidates for packaging applications.

Capillary electrophoresis is a powerful separation technique for analysis of proteins and peptides, with benefits like low consumption of reagents, solvents and sample. The separation efficiency and resolution can be deteriorated by adsorption of analytes to the inner capillary wall, though. Many methods to circumvent this obstacle have been reported, including background electrolyte addition of surfactants that aggregate as protective coatings at the wall. In this work, anionic suberin surfactant was used together with the cationic surfactant cetyltrimethylammonium bromide (CTAB) for analysis of trypsin digested lysozyme as a model sample. Suberin fatty acids were extracted from birch bark, which is a side-stream product originating from pulp and paper waste streams. Different adjustments of the solvent extraction protocol, and the method to neutralize the suberin fatty acids to obtain surface active sodium salts were evaluated regarding number of peaks observed, separation repeatability, and analysis time. The influence of background electrolyte pH was also studied. The potential of the surface-active sodium salts of suberin fatty acids as an additive enhancer in combination with CTAB is illustrated by excellent repeatability, especially at lower pH values. The number of peaks observed was also higher at lower pH, while the analysis time was shorter.

To fulfill the United Nations’ 17 sustainable development goals, there is a need to transition from a petroleum-based society toward a more sustainable one which requires new solutions and the production of materials, chemicals, and energy from renewable resources. Using side-stream products from industries to produce value-added products will be economically beneficial. Furthermore, finding more environmentally friendly process routes will aid industries in achieving their goal of reducing carbon dioxide emissions and contributing to a more sustainable society.

Tree bark is the outer protective layer of a tree and today, mills and factories incinerate the bark to produce energy. Norway spruce (Picea abies) bark consistsof cellulose, lignin, hemicellulose, and extractives. Applying the biorefinery concept makes it possible to extract and isolate these compounds in the bark and utilize them to produce high-value materials and chemicals.

This thesis applies the biorefinery concept to isolate cellulose and lignin from spruce bark by using mild extraction processes and more eco-friendly chemicals.

Cellulose is the most abundant compound in spruce bark and has great potential to be used in various applications. The isolation of cellulose fibers from bark was in the present work carried out by first removing the extractives and non-cellulosic polysaccharides via sequential extractions using acetone and subcritical water. Nanocellulose was isolated from the bark cellulose and used to produce Pickering emulsions successfully. This proves that using side-stream products such as bark is feasible to produce high-value products like emulsions.

Lignin is the second most abundant compound in the spruce bark. Following the acetone and subcritical water extractions, a mild cyclic organosolv extraction sequence was applied to be able to recover spruce bark lignin. The lignin extracted was comparable to lignin extracted from wood. Stilbene glucosides incorporated in the bark lignin provide the lignin with additional beneficial properties, i.e., antimicrobial and antioxidative. This elevates the value of the lignin further and makes it suitable for a variety of different applications.

För att kunna uppnå Förenta Nationernas 17 globala hållbarhetsmål behöverdet ske en förändring från ett oljebaserat samhälle till ett mer hållbart samhälle. Detta innebär att det finns ett behov för nya hållbara lösningar och material, kemikalier och energi som produceras med förnybara råvaror. Att utnyttja sidoströmmar från industrier för att producera högvärdiga produkter kommer vara ekonomiskt fördelaktigt. Dessutom, att finna mer miljövänliga processer kommer att bidra till att hjälpa industrier att uppnå deras mål med att minska koldioxidutsläppen och bidra till ett mer hållbart samhälle.

Trädbark är det yttersta skyddande lagret på ett träd och idag förbränner bruk och fabriker den för att skapa energi. Granbarken består av cellulosa, lignin, hemicellulosa, och extraktivämnen. Att använda bioraffinaderikonceptet gör det möjligt att extrahera och isolera komponenterna i barken och vidare producera högvärdiga material och kemikalier.

Denna avhandling applicerar bioraffinaderikonceptet för att isolera cellulosa och lignin från den inre granbarken genom att använda milda extraktionsprocesser och mer miljövänliga kemikalier.

Cellulosa är den vanligaste förekommande komponenten i bark och har stor potential att användas för olika tillämpningar. Isoleringen av cellulosafibrer från bark genomfördes i detta arbete först genom att avlägsna extraktivämnen och icke-cellulosahaltiga polysackarider via sekventiella extraktioner med aceton och subkritiskt vatten. Nanocellulosa isolerades från barkcellulosan och användes för att producera Pickering emulsioner med framgång. Detta visar att det är möjligt att utnyttja en produkt såsom bark från en sidoström till att skapa högvärdiga produkter som emulsioner.

Lignin är den näst mest vanligt förekommande komponenten i bark. Efter extraktion med aceton och subkritiskt vatten genomgick barkfibrerna en sekventiell cyklisk organosolv-extraktion för att erhålla gransbarkslignin. Det extraherade ligninet var jämförbart med lignin som extraherats från ved. Stilbene glykosider som är inkorporerade i barkligninet ger ligninet ytterligare fördelaktiga egenskaper, exempelvis antimikrobiella och antioxidativa. Detta förhöjer värdet ännu mer och gör den lämplig för flera olika tillämpningar.

Tree bark is normally a side-stream product but by an integrated bark biorefinery approach, valuable compounds may be recovered and used to replace fossil-based products. Norway spruce bark was extracted to obtain cellulose, which was chemically treated to produce cellulose oxalate (COX) which was homogenized to yield nanocellulose. The nanocellulose was used to produce Pickering emulsions with almond oil and hexadecane as organic phases. COX from dissolving pulp was used to study the effect of various raw materials on the emulsifying properties. The COX samples of bark and dissolving pulp contained a significant amount of hemicelluloses, which affected the viscosity results. The emulsion properties were affected by the organic phases and the aspect ratio. Emulsions using hexadecane were more stable than the emulsions using almond oil. Since the aspect ratio of bark was lower than that of the dissolving pulp, the emulsifying properties of the COX dissolving pulp was better. It has been shown that nanocellulose from cellulose oxalate of both spruce bark and dissolving pulp is a promising substitute for petroleum-based emulsifiers and surfactants. By utilizing bark, value-added products can be produced which may be economically beneficial for various industries in the future and their aim for climate-neutral products.

Many of the amphiphilic molecules, or surfactants, are produced from fossil-based raw materials. With the increasing awareness of the climate situation, focus has shifted toward more environmentally friendly solutions to replace fossil-based products. This has led to more interest towards the forest. The circular bioeconomy is focused on making use of residues and waste and on optimizing the value of biomass over time via cascading. Nowadays, bark is seen as a waste product by industries and mainly incinerated as solid fuel. The bark contains interesting compounds but some of these are only available in low amounts, less than 1 % in the bark, while other components are present in several percentages. However, some of these components are potential candidates for the manufacture of amphiphiles and there seems to be a strong match between bark availability and surfactant demand. The global amount of bark available is approximately 359 million m3 and more than 10 million m3 of industrial bark are generated annually in Sweden and Finland. The bark of Norway spruce, Scots pine and silver birch contains approximately 25-32 % of extractives and part of these extractives has a potential as a surfactant backbone. This matches the global surfactant demand of about 15.6 million tons. Therefore, industrial bark has a significant potential value as a raw material source for amphiphilic molecules and polymers. This review focuses on betulin, condensed tannin and suberin. These compounds have been studied on individually and methods to extract them out from the bark are well investigated, but to utilize them as amphiphilic compounds has not been explored. With this review, we want to emphasis the potential of using bark, what today is seen as a waste product, as a raw material for production of amphiphiles. Moreover, a techno-economic analysis has been performed on betulin, tannins and suberin. 

The interest in the bark and the attempt to add value to its utilization have increased over the last decade. By applying an integrated bark biorefinery approach, it is possible to investigate the recovery of compounds that can be used to develop green and sustainable alternatives to fossil-based materials. In this work, the focus is on extracting Norway spruce (Picea abies) bark lignin via organosolv extraction. Following the removal of the extractives and the subcritical water extraction to remove the polysaccharides, a novel cyclic organosolv extraction procedure was applied, which enabled the recovery of lignin with high quality and preserved structure. Main indicators for low degradation and preservation of the lignin structure were a high β-O-4' content and low amounts of condensed structures. Furthermore, high purity and low polydispersity of the lignin were observed. Thus, the obtained lignin exhibits high potential for use in the direct development of polymer precursors and other bio-based materials. During the extraction sequence, around 70% of the bark was extracted. Besides the lignin, the extractives as well as pectic polysaccharides and hemicelluloses were recovered with only minor degradation, which could potentially be used for the production of biofuel or other high-value products such as emulsifiers or adhesives.

Micro-sized cellulosic materials are promising reinforcements for thermoplastic composites. In this study, a new type of microcellulose - cellulose oxalate (COX) was used as reinforcement for polypropylene-based composites and its reinforcing effect was evaluated. COX and microcrystalline cellulose (MCC), which was used for comparison, were subjected to ball milling process for different times to obtain milled cellulose powders. Ternary composites consisting of 60 wt% polypropylene (PP) as the matrix, 10 wt% maleic anhydride grafted polypropylene (MAPP) as the coupling agent and 30 wt% milled or non-milled cellulose powder as reinforcement were prepared by melt-extrusion and injection molding. Tensile test results showed that 1 h milled COX-containing composite exhibited the best tensile properties (e.g., tensile strength and Young's modulus are 16.1% and 106.0% respectively higher than those of neat PP) and MCC generally exhibited a poorer reinforcing effect than COX with same milling time.