Browsing by Author "Eilamo, Tomi"
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Item Condensation of extractive compounds in fresh wood(2019-06-10) Ruuttunen, Kyösti; Vuorinen, Tapani; Eilamo, Tomi; Saranpää, Pekka; Department of Bioproducts and Biosystems; Wood ChemistryPrevious research shows that phenolic compounds present in xylem sap are susceptible to polymerization in the presence of oxygen. Our aim is to investigate this polymerization and pos-sible condensation in wood matrix: what is the effect on the wood material’s properties? A single birch tree (Betula sp.) with a diameter of ca. 13 cm was felled in Western Finland in late autumn, immediately packed airtight and stored in a freezer below -18 °C. The wood was ground to a fine sawdust with a hole saw. Two treatments were performed: 1. Fresh Extraction (FE): Sawdust was immediately immersed in a solvent (acetone-water 4:1) in a closed vessel. Extraction was carried out at room temperature (RT; 25 h), then vacuum filtered through a cellulose paper. 2. Dry Extraction (DE): Sawdust was air-dried for 5 days at room temperature, and then ex-tracted (acetone-water 4:1) and vacuum filtered. Acetone was evaporated under vacuum (25-35 °C). Prior of the freeze-drying the pH of the re-maining water solution was measured. Samples of FE and DE sawdust were compressed into thin disks (diameter ca. 45 mm) for optical measurements. The FE and DE extracts were charac-terized further with UV-vis spectroscopy and GC. The reactivity of the FE and DE samples was tested in autohydrolysis experiments (P factor 800, 150 and 205 °C). The preliminary results indicate: • drying of wood prior to extraction caused a distinct yellow hue. • after autohydrolysis, the Klason lignin content was higher in the dry-extracted wood compared to the fresh-extracted. The preliminary results suggest that some of the (phenolic) extractive components in fresh birch sap polymerize or condense with other wood components during air-drying. The reaction seems to be irreversible: the colored components cannot be removed with extraction. Details of the chemical changes in the extractive compounds, as well as in the wood matrix, will be reported in the near future, when all the ongoing experiments are finalized.Item Creating sustainability reporting for company - Case Nordic Bioproducts Group(2023-06-13) Sergeeva, Darja; Auranen, Anneli; Eilamo, Tomi; Kemian tekniikan korkeakoulu; Hughes, MarkItem The effect of manufacturing parameters on regenerated cellulose film properties(2022-10-18) Talvitie, Maisa; Eilamo, Tomi; Kemian tekniikan korkeakoulu; Kontturi, EeroPetroleum-based plastics are creating environmental problems owing to their toxic properties and non-biodegradability. Biopolymers, such as cellulose, could replace fossil-based polymers in the packaging industry and help alleviate the burden on the environment. Cellulose can be fabricated into regenerated cellulose film (RCF) via the dissolution-regeneration process. RCFs are biodegradable, nontoxic, and sustainable and, generally, have excellent optical and mechanical properties, and good barriers to oxygen and grease. Nevertheless, the possible applications have been limited by the hydrophilic nature of the films. This master’s thesis highlights different cellulose solvent systems, the regeneration mechanism as well as the influencing factors that affect the mechanical, optical and barrier properties of RCFs. The aim of the work was to examine the film manufacturing parameters in order to improve the mechanical, optical, and water intake properties. The manufacturing parameters altered in the experiment were concentration and temperature of the coagulation bath, plasticizer concentration as well as drying temperature. The films fabricated in this study exhibited even better transparency than the commercial cellophane. The tensile strength values varied between 20 and 43 MPa and the plasticizer content and drying rate had the most effect on the results. The contact angle and water vapor transmission rate tests as well as the moisture adsorption measurement demonstrated that the films were hydrophilic, however, the films could be made more hydrophobic by decreasing plasticizer content and drying rate and increasing acid concentration in coagulation. In the context of these results, regenerated cellulose films have great potential to replace fossil-based plastics and aid in mitigating the environmental problems caused by the plastic industry.Item Effect of prehydrolysis on delignification efficiency of hemp hurds(2022-08-23) Inkeroinen, Camilla; Eilamo, Tomi; Kemian tekniikan korkeakoulu; Kontturi, EeroThe aim of this thesis was to study hemp hurd biomass as a possible cheap source of cellulose-rich pulp and determine the effect that a diluted acid hydrolysis pretreatment has on the delignification of hemp biomass. Earlier studies have concluded that hemp is harder to delignify while maintaining good yields when compared to hardwoods. In this work, hemp biomass was pretreated with dilute acid hydrolysis at different temperatures. After pretreatment hemp was delignified via kraft pulping. Results were compared to non-pretreated hemp biomass delignified the same way. Dilute acid hydrolysis before kraft pulping shows some positive results when compared to samples with no pretreatment. This positive effect is only present in samples pulped in low H-factors where residual alkali amount is relatively high and lignin condensation is most unlikely to occur. As fibrillation did not occur in any of the samples and the lowest pulping yield was around 55% for 22 % alkalinity soda pulping, none of the hurd delignifications can be considered successful. The best results from prehydrolysis kraft pulping results were achieved via prehydrolysis in 160 °C with 2 % acid charge of dry pulp weight. During this work it was noticed that the delignification efficiency of hemp hurds does not correlate with the kappa number determined for the pulp as the HexA production during kraft pulping is high. Hemp hurds seem to respond better to soda pulping than kraft pulping producing less HexA while pulping.Item Oxidation reactions of phenolic extractive compounds in wood(2020-03-17) Eilamo, Tomi; Ruuttunen, Kyösti; Saranpää, Pekka; Kemian tekniikan korkeakoulu; Vuorinen, TapaniThis thesis investigated the oxidation of phenolic extractive compounds in fresh wood immediately after the structure of wood is broken and the compounds come in contact with each other, ambient air and light at room temperature. Experimental part was conducted by sawing frozen birch wood to sawdust and then extracting it immediately with 80% acetone. Some sawdust was dried before acetone extraction and used as a comparison. Color of the sawdust samples was measured using CIELAB measurements and the reactivity of the samples was assessed by autohydrolysis trials. Extracts were analyzed using GC-MS, GC-FID, HPAEC and UV-vis spectrometry. There was a clear difference in the colors of the sawdust samples after acetone extraction. Dried samples had darkened visibly during drying and the extraction did not remove the colored compounds from the sawdust. Immediate extraction after sawing also yielded more extractives and the immediately extracted sawdust had less acetone soluble content after autohydrolysis than dried sawdust. Extract from immediately extracted sawdust contained (-)-epicatechin and sucrose that were present in extract from dried sawdust samples in significantly smaller quantities or in some cases completely absent. Conversely, glucose and fructose contents were higher in the extract from dried sawdust. A clear correlation between the disappearance of (-)-epicatechin in the extract and the discoloration during drying in sawdust could be seen. This enforces the theory that polyphenols are a key component in wood discoloration after felling.Item Selluloosan TEMPO-oksidointi nanokuiduiksi(2016-05-08) Eilamo, Tomi; Salminen, Reeta-Maaret; Kemiantekniikan korkeakoulu; Hiltunen, Eero