| 1. |
- Andersson, Kerstin, et al.
(författare)
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Effects of biological treatment on the chemical structure of dissolved lignin-related substances in effluent from thermomechanical pulping
- 2008
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 23:2, s. 164-171
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Tidskriftsartikel (refereegranskat)abstract
- Effluent from a TMP-based pulp and paper mill was collected at the inlet and outlet of the mill's biological treatment plant and fractionated by sorption on XAD-8 resin and MTBE precipitation. Fractionation indicated that the refractory dissolved organic material in biologically treated effluent was mainly composed of lignin-related substances. Characterisation of the lignin-related substances by chromatographic and spectrometric methods confirmed the similarities of the isolated material and milled wood lignin. Fractionation and characterisation of alkali-extracted material from solids (biosludge) in biologically treated effluent found evidence of lignin-related material. Results indicated that biological treatment had altered the chemical structure and molar-mass distribution of dissolved lignin-related substances.
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| 2. |
- Andersson, Kerstin I., et al.
(författare)
-
Effects of biological treatment on the chemical structure of dissolved lignin-related substances in effluent from thermomechanical pulping
- 2008
-
Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 23:2, s. 164-171
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Tidskriftsartikel (refereegranskat)abstract
- Effluent from a TMP-based pulp and paper mill was collected at the inlet and outlet of the mill's biological treatment plant and fractionated by sorption on XAD-8 resin and MTBE precipitation. Fractionation indicated that the refractory dissolved organic material in biologically treated effluent was mainly composed of lignin-related substances. Characterisation of the lignin-related substances by chromatographic and spectrometric methods confirmed the similarities of the isolated material and milled wood lignin. Fractionation and characterisation of alkali-extracted material from solids (biosludge) in biologically treated effluent found evidence of lignin-related material. Results indicated that biological treatment had altered the chemical structure and molar-mass distribution of dissolved lignin-related substances.
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| 3. |
- Duanmu, Jie, et al.
(författare)
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Allyloxy-modified starch with low degree of substitution for fiber reinforced thermoset starch composites
- 2011
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Ingår i: Composites Science And Technology. - : Elsevier BV. - 0266-3538 .- 1879-1050. ; 71:4, s. 520-527
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Tidskriftsartikel (refereegranskat)abstract
- In the present work dough moulding compound premixes of allyl glycidyl ether modified (AGE)-potato starch, (DS) = 0.2, has been prepared and tested for its fiber reinforced composite properties. The AGE-starch was hydrolyzed with a-amylase under neutral condition for 6 h at 45 degrees C for improved process ability. The grafting and hydrolytic scission was confirmed by nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), respectively. Homogeneous composite premixes of AGE-starch, wood fibers, various amount of glycerol and ethylene glycol dimethacrylate were successfully mixed with a Brabender-kneader at 55 degrees C and cured by compression molding at 150 degrees C using 2 wt% of dibenzoyl peroxide. Adding 5 wt% of glycerol did not reduce the ultimate strength of the composites: 10% glycerol reduced the strength from 60 MPa to 40 MPa, and 16% glycerol to 14 MPa. The results with 5 wt% glycerol are comparable with earlier achieved results. The water absorption rate increased with increased glycerol content and the mechanical strength of the composites was lost completely when the moisture uptake reached 15 wt%.
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| 4. |
- Duanmu, Jie, et al.
(författare)
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Studies on mechanical properties of wood fiber reinforced cross-linked starch composites made from enzymatically degraded allylglycidyl ether-modified starch
- 2010
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier BV. - 1359-835X .- 1878-5840. ; 41:10, s. 1409-1418
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Tidskriftsartikel (refereegranskat)abstract
- In a previous work we introduced a new family of thermoset composites of softwood fiber and allylglycidyl ether modified potato starch (AGE-starch with a degree of substitution of 1.3 and 2.3) prepared by hot pressing. To improve the processability of AGE-starch with a DS = 1.3 (LDS-3) and to increase hygromechanical properties, the LDS-3 matrix has now been partially degraded by a-amylase at 45 degrees C (pH 6) for 0.5, 6 and 18 h. The study shows that already a 30 min enzymatic hydrolysis has a marked effect on the modified starch molecular weight and its thermal properties. The new composites with enzyme hydrolyzed AGE-starch, generically named D-LDS-3, showed good fiber dispersion and excellent interface between the fiber and matrix as studied by SEM. Premixes of D-LDS-3 matrix and fiber showed improved processability. The water vapor absorption was evaluated at 43.2% and 82.2% RH and the stiffness and strength properties were measured. The water uptake was shown to be reduced. The strength of neat matrix D-LDS-3-6 at ambient 68% RH reached 63 MPa and Young's modulus 3200 MPa and with 40 wt.% wood fiber reinforcement impressive 128 MPa and 4500 MPa, respectively.
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| 5. |
- Gulbrandsen, Torea A., et al.
(författare)
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Extracting hemicelluloses from softwood and bagasse as oligosaccharides using pure water and microwave heating
- 2015
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Ingår i: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 49:2, s. 117-126
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the study was to identify conditions for hemicelluloses extraction in oligomeric form. Using microwave assisted hot water extraction (HWE), the effects of both retention time and temperature on hemicelluloses yields, as well as the degree of polymerization (DP) as analyzed by SEC-MALLS, were investigated using both softwood (sawmill shavings) and sugarcane bagasse. The results are discussed in the light of the unavoidable yield-DP compromise resulting from the application of batch mode operations. Nevertheless, significant differences between the two raw materials could be observed, as expected. For softwood shavings, data interpolation indicated that about 50% of the hemicelluloses could be obtained as oligomers at an average DP of 30 when extracted at 183 °C for 5 minutes. For bagasse, longer extraction times seemed optimal. After hot water extraction at 183 °C for 12 minutes, about 62% of the bagasse hemicelluloses were extracted as oligomers at an average DP of about 100.
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| 6. |
- Kisonen, Victor, et al.
(författare)
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Cationised O-acetyl galactoglucomannans : Synthesis and characterisation
- 2014
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 99, s. 755-764
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Tidskriftsartikel (refereegranskat)abstract
- Water-soluble O-acetyl-galactoglucomannans (GGMs) can be obtained from Norway spruce by hot-water-extraction of the wood or as a side product by ultrafiltration of mechanical pulping waters. Cationic and amphiphilic polysaccharides and their derivatives are of interest for a number of applications and thus quaternary nitrogen moieties with cationic charge were grafted onto GGMs in the heterogeneous reaction to render a cationic polyelectrolyte. The degree of substitution was measured by elemental analysis of nitrogen, by quantitative C-13 NMR and interestingly also by polyelectrolyte titration and the results were congruent. NMR, matrix-assisted laser desorption/ionisation mass spectroscopy (MALDI-TOF-MS), and FT-IR analysis were used to characterise the product. THF or DMSO with water enhanced the reaction efficiency and decreased M-w reduction in comparison to plain water as a reaction media. Cationised GGM was also successfully acetylated. The cationic derivatives of hemicelluloses can potentially be utilised as polyelectrolyte layers in packaging and pharmaceutical applications.
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| 7. |
- Tarasov, Dmitry, et al.
(författare)
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AqSO biorefinery : a green and parameter-controlled process for the production of lignin-carbohydrate hybrid materials
- 2022
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 24:17, s. 6639-6656
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Tidskriftsartikel (refereegranskat)abstract
- The current biorefineries are focused on the comprehensive fractionation of biomass components into separate lignin and carbohydrate fractions for the production of materials, platform chemicals and biofuel. However, it has become obvious that the combination of lignin and carbohydrates can have significant technical, environmental, and economic benefits as opposed to their separate use. Herein, we developed a green, simple, and flexible biorefinery concept for the integrated utilization of all major biomass components for high-value applications with the focus on functional lignin–carbohydrate hybrids (LCHs). The established process consisted of a modified hydrothermal treatment (HTT) of birch wood followed by solvent extraction of the resulting solids and is therefore named AquaSolv Omni (AqSO) biorefinery. The AqSO biorefinery produces three major streams: hydrolysate (hemicellulose-derived products), solvent-extracted lignin–carbohydrate complexes (LCCs) and cellulose-rich fibers. Specific process conditions were found to facilitate the production of LCCs of different types in high yields as a new valuable and industrially realistic process stream. The effect of the process severity and liquid to solid (L/S) ratio on the yields and compositions of the produced fractions as well as on the structure and properties of the extracted LCCs was investigated using state of the art NMR spectroscopy and molar mass distribution analysis among other methods. The high flexibility of the process allows for engineering of the resulting products in a wide range of chemical compositions, structures and physicochemical properties and therefore gives a good opportunity to optimize the products for specific high-value applications. The process can be easily combined with other biorefinery operations (e.g., enzymatic hydrolysis, pulping, bleaching) to be incorporated into existing value chains or create new ones and thus is suitable for different biorefinery scenarios. First examples of high-value applications of AqSO biorefinery LCHs are reported. LCC nanoparticles (LCCNPs) were produced for the first time directly from the solvent extract and their properties were investigated. LCCNPs could efficiently stabilize Pickering emulsions of tetrahydrofurfuryl methacrylate and allowed their free radical polymerization. In addition, AqSO LCHs showed promising results as wood adhesives. Overall, our results provide detailed information on the complex lignocellulosic fractions and bridge the gap from process engineering to sustainable product development.
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