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The impact of extraction severity on polymeric hemicelluloses isolated from rapeseed straw
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-2041-5786
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-8992-3623
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-1631-1781
(English)Manuscript (preprint) (Other academic)
National Category
Polymer Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-185843OAI: oai:DiVA.org:kth-185843DiVA: diva2:924351
Funder
Swedish Research Council Formas
Note

QC 20160428

Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2016-04-28Bibliographically approved
In thesis
1. Extraction of polymeric rapeseed straw hemicelluloses for renewable films
Open this publication in new window or tab >>Extraction of polymeric rapeseed straw hemicelluloses for renewable films
2016 (English)Licentiate 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.

Place, publisher, year, edition, pages
Stockholm: Kungliga Tekniska högskolan, 2016. 55 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2016:16
Keyword
rapeseed straw/canola straw, hemicellulose, xylan, mannan, extraction, characterization, severity factor, hemicellulose film
National Category
Polymer Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-185737 (URN)978-91-7595-939-9 (ISBN)
Presentation
2016-05-20, K2, Teknikringen 28, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council Formas, 2013-844
Note

QC 20160428

Available from: 2016-04-28 Created: 2016-04-26 Last updated: 2016-04-28Bibliographically approved

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Svärd, AntoniaBrännvall, ElisabetEdlund, Ulrica
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