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  • 1.
    Edlund, Ulrica
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svärd, Antonia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sterner, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wahlström, Niklas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Engineered polysaccharide materials from biorefining of terrestrial and marine biomass2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 2.
    Svärd, Antonia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Extraction of polymeric rapeseed straw hemicelluloses for renewable films2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Polymeric hemicelluloses with high molecular weight were extracted from rapeseed straw with a straight forward hydrothermal extraction method, evaluated and refined by statistical factorial screening design and ‘severity factor’ analysis. The influence of the extraction conditions, time, temperature and pH of the extraction liquid, on the composition, molecular weight, yield and properties was unveiled. The initial statistical screening design provided critical knowledge in how the extraction parameters affect yield, lignin and sugar composition as well as molecular weight of the extracts. A more elaborate extraction study which encompassed a greater temperature range and variation of the pH in the hydrothermal liquid combined with ‘severity factor’ modeling on the molecular weight of the extracts provided deeper insights of the effect of the extraction conditions. Water and acid extraction resulted in glucomannan rich extracts. Glucomannan isolated with acid was more degraded than the glucomannan isolated with water. From an environmentally perspective water extraction is preferred to obtain glucomannan due to the corrosive nature of acid. The molecular weight of the dissolved glucomannan during water extraction increased with temperature. Xylan was co-extracted at the higher extraction temperature. Alkaline extraction yielded an extract rich in xylan, where the total amount and the molecular weight of xylan increased with alkali charge. The xylan was more degraded at the highest temperature, 140 °C, and the highest alkali charge. All different extractions yielded co-extracted lignin, especially during high charge of alkali, but the straw was never fully delignified or the cellulose fibres liberated. Some extracts, selected from the statistical screening study, were utilized as raw materials for renewable plastic films.  The glucomannan films were very fragile, while the xylan films had remarkable strain-at-break of 60 – 80 % without any added plasticizer.

  • 3.
    Svärd, Antonia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Brännvall, E.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Modified and thermoplastic rapeseed straw xylan: A renewable additive in PCL biocomposites2018In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 119, p. 73-82Article in journal (Refereed)
    Abstract [en]

    Xylan extracted from rapeseed straw was chemically modified to gain hydrophobic and thermoplastic properties via macroinitiator formation followed by a free radical grafting-from polymerization with octadecyl acrylate. Biocomposites were then prepared by incorporation of 5 or 20% (w/w) rapeseed straw xylan into a poly(epsilon-caprolactone) (PCL) matrix by melt extrusion. The grafted xylan was homogeneously distributed within the biocomposite and reinforced the PCL matrix while at the same time preserving the ability to elongate to tensile strains > 500%. Analogous biocomposites made from unmodified xylan in a PCL matrix resulted in heterogeneous mixtures and brittle tensile properties.

  • 4.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Brännvall, Elisabet
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Corrigendum to “Rapeseed straw as a renewable source of hemicelluloses: Extraction, characterization and film formation” [Carbohydrate Polymers 133 (2015) 179–186](S0144861715006529)(10.1016/j.carbpol.2015.07.023)2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 174, p. 1240-Article in journal (Other academic)
    Abstract [en]

    The authors regret that the original version of this article unfortunately contained a mistake in Table 5. The correct Table 5 and associated text is given below. “The rapeseed hemicellulose films presented here had strain-at-break values of 70% (C) and 90% (H), even with no added plasticizers (Table 5).” The authors would like to apologise for any inconvenience caused.

  • 5.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Brännvall, Elisabet
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Rapeseed straw as a renewable source of hemicelluloses: Extraction, characterization and film formation2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 133, p. 179-186Article in journal (Refereed)
    Abstract [en]

    Polymeric hemicelluloses were extracted by autohydrolysis and alkali from a biomass feed consisting of the stems of rapeseed straw according to a full statistical factorial screening design. Water extraction yielded fractions rich in galactoglucomannan, while alkaline extraction yielded primarily xylan. The extracted galactoglucomannan and xylans had similar molecular weights, while the yield of xylan was higher than the yield of galactoglucomannan. The extracted hemicellulose fractions also contained some lignin (7-15%) and traces of Ca, K, Na, and Si. Free-standing films were prepared from the hemicellulose fractions with different xylan:galactoglucomannan ratios. The rapeseed xylan films showed strain-to-break values >60% without any added plasticizers.

  • 6.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Royal Inst Technol, Sch Chem Sci & Technol, Fiber & Polymertechnol, Stockholm, Sweden..
    Brännvall, Elisabet
    KTH. Royal Inst Technol, Stockholm, Sweden..
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Royal Inst Technol KTH, Fibre & Polymer Technol, Stockholm, Sweden..
    Rapeseed straw extraction yields hemicelluloses for renewable materials2016In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal (Other academic)
  • 7.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Brännvall, Elisabet
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Rapeseed straw polymeric hemicelluloses obtained by extraction methods based on severity factor2017In: INDUSTRIAL CROPS AND PRODUCTS, ISSN 0926-6690, Vol. 95, p. 305-315Article in journal (Refereed)
    Abstract [en]

    Rapeseed straw consists of a hard epidermis that is rich in hemicellulose and lignin and a sponge-like interior that consists mainly of cellulose. The stems were subjected to water, alkali or acid as extraction medium. The effects of the extraction conditions were quantified using severity factors and by comparing the effects of different extraction pHs, temperatures and times. Extraction with alkali resulted in a higher yield, 47 g/100 g straw in, compared to water, 6 g/100 g straw in, or an acidic, 5 g/100 g straw in, extraction process. An increase in temperature improved the extraction yield; in particular, more xylan was extracted at an elevated temperature and higher alkalinity. However, at high alkalinity, increased extraction temperatures led to a reduction in the recovery of glucomannan. The highest molecular weights (similar to 35,000 g/mol) of the extracted hemicelluloses were obtained using extraction procedures with 1.5 M NaOH at 110 degrees C and autohydrolysis at 150 degrees C. While these two parameter settings had very similar severity factors, extraction under basic conditions afforded an extract rich in xylan and low in lignin content, whereas autohydrolysis generated a glucomannan-rich extract.

  • 8.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Brännvall, Elisabet
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    The impact of extraction severity on polymeric hemicelluloses isolated from rapeseed strawManuscript (preprint) (Other academic)
  • 9.
    Svärd, Antonia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Moriana, Rosana
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. School of Engineering Science, HIS-University Skövde, Högskolevägen, Skövde.
    Brannvall, Elisabet
    RISE Bioecon, Box 5604, SE-11486 Stockholm, Sweden..
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Rapeseed Straw Biorefinery Process2019In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, no 1, p. 790-801Article in journal (Refereed)
    Abstract [en]

    A rapeseed straw biorefinery process was demonstrated with more than 50% of the straw recovered as products. Xylan with a weight-average molecular weight of 56 760 g/mol was extracted in an alkaline step. The straw residue was subjected to soda pulping, resulting in cellulose-rich fibers and a lignin-rich liquid fraction. The lignin contained syringyl and guaiacyl aromatic structural units in a 1/0.75 ratio. The cellulose pulp was bleached, resulting in a cellulose fraction of 85% purity and a crystallinity index (CI) of 83%. Two grades of nanocellulose, CNF and CNC, were isolated from the bleached pulp. The CNF was very heterogeneous in size with an average diameter of 4 nm and an average length of 1177 nm. The CNC had an average diameter of 6 nm and an average particle length of 193 nm. CNF and CNC had good thermal stability and an aspect ratio of 294 and 32, respectively.

  • 10.
    Svärd, Antonia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Sevastyanova, Olena
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Dobele, Galina
    Jurkjane, Vilhemina
    Brännvall, Elisabet
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    COST Action FP1105: effect of raw materials and pulping conditions on the characteristics of dissolved kraft lignins2016In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 70, no 12, p. 1105-1114Article in journal (Refereed)
    Abstract [en]

    The composition, molecular weight (MW), and chemical structure of technical lignins as byproducts of pulping influence their application in terms of physical and chemical properties, reactivity, and performance. It is important to know how the analytical data of technical lignins are influenced by the wood species and the parameters of pulping. The present study focuses on kraft pulping and how the wood species (eucalyptus, pine, and spruce) and variable cooking times influence the characteristics of dissolved lignins. The black liquor (BL) was recovered after three different cooking times and the precipitated lignin was characterized by total acid hydrolysis including the determination of the acid insoluble part (Klason lignin, KL) and the sugars in the hydrolysate, elemental analysis, 31P NMR spectroscopy, analytical pyrolysis (Py-GC/MS), gel permeation chromatography (GPC), thermogravimetry (TG), and differential scanning calorimetry (DSC). The results indicate that the phenolic OH content, MW and glass transition temperature increased with longer cooking times for the softwood (SW) lignins. These lignins had also a higher MW (M-w 5500-8000 g mol(-1)), than the eucalyptus lignin (M-w 2200-2400 g mol(-1)). Eucalyptus lignin had higher sulfur content compared to SW.

  • 11.
    Svärd, Antonia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sterner, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Bioplastics and composites from plant heteropolysaccharides2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
1 - 11 of 11
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  • harvard1
  • ieee
  • modern-language-association-8th-edition
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  • en-US
  • fi-FI
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