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Rapeseed straw as a renewable source of hemicelluloses: Extraction, characterization and film formation
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.ORCID-id: 0000-0002-2041-5786
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.ORCID-id: 0000-0002-8992-3623
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.ORCID-id: 0000-0002-1631-1781
2015 (Engelska)Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 133, s. 179-186Artikel i tidskrift (Refereegranskat) Published
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.

Ort, förlag, år, upplaga, sidor
2015. Vol. 133, s. 179-186
Nyckelord [en]
Rapeseed/canola straw, Extraction, Autohydrolysis, Alkaline extraction, Xylan, Glucomannan, Film
Nationell ämneskategori
Polymerkemi
Identifikatorer
URN: urn:nbn:se:kth:diva-175899DOI: 10.1016/j.carbpol.2015.07.023ISI: 000361920900024PubMedID: 26344270Scopus ID: 2-s2.0-84937926293OAI: oai:DiVA.org:kth-175899DiVA, id: diva2:870276
Forskningsfinansiär
Forskningsrådet Formas, 2013-844
Anmärkning

QC 20151113

Tillgänglig från: 2015-11-13 Skapad: 2015-10-26 Senast uppdaterad: 2018-09-07Bibliografiskt granskad
Ingår i avhandling
1. Extraction of polymeric rapeseed straw hemicelluloses for renewable films
Öppna denna publikation i ny flik eller fönster >>Extraction of polymeric rapeseed straw hemicelluloses for renewable films
2016 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Stockholm: Kungliga Tekniska högskolan, 2016. s. 55
Serie
TRITA-CHE-Report, ISSN 1654-1081 ; 2016:16
Nyckelord
rapeseed straw/canola straw, hemicellulose, xylan, mannan, extraction, characterization, severity factor, hemicellulose film
Nationell ämneskategori
Polymerkemi
Forskningsämne
Kemi
Identifikatorer
urn:nbn:se:kth:diva-185737 (URN)978-91-7595-939-9 (ISBN)
Presentation
2016-05-20, K2, Teknikringen 28, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Forskningsfinansiär
Forskningsrådet Formas, 2013-844
Anmärkning

QC 20160428

Tillgänglig från: 2016-04-28 Skapad: 2016-04-26 Senast uppdaterad: 2016-04-28Bibliografiskt granskad
2. Biopolymers and materials from rapeseed straw biorefining
Öppna denna publikation i ny flik eller fönster >>Biopolymers and materials from rapeseed straw biorefining
2018 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Rapeseed straw was fractionated through a hydrothermal process into its hemicellulose, lignin and cellulose components. In the first step, hemicellulose-rich fractions were extracted. Xylan-rich fractions with high molecular weight, 30,000 – 50,000 g/mol, were obtained at 110 °C and 1.5 M NaOH. Neutral and acidic conditions yielded extract rich in glucomannan with co-extracted xylan and lignin.After hemicellulose extraction, the straw was subjected to a soda cooking step where the straw was delignified and lignin solubilized. Two cooking times were evaluated in this step. A longer cooking time resulted in a lignin-rich precipitate and a cellulose pulp with a lower content of lignin compared with the shorter cooking time. Analysis showed rapeseed straw lignin consists of syringyl and guaiacyl aromatic structures. Peroxide bleaching of the pulp decreased the lignin content in the cellulose pulp further. Cellulose nanoparticles (CNF and CNC) were isolated from the bleached pulp. The CNF fraction was heterogenous in size while the CNC fraction was more homogenous in size with rod like aspects. Both were highly crystalline, with good thermal stability and high aspect ratio.Thin free-standing films of xylan were cast from water solution with mechanical integrity and very high strain-at-break > 80% even without added plasticizer.A surface modification process was developed where xylan was first pre-activated in alkali. This was followed by an etherification coupling reaction with glycidyl methacrylate and subsequently grafted by interfacial free radical graft polymerization with octadecyl acrylate chains. The resulting grafted xylan became hydrophobic and gained a thermoplastic behavior. It was blended with PCL matrix via melt-extrusion. The grafted xylan was homogeneously distributed within the biocomposite and the PCL matrix was reinforced while at the same time preserving the ability to elongate to tensile strains > 500%. Analogous biocomposites with unmodified xylan in a PCL matrix resulted in heterogenous mixtures and brittle tensile properties.

Ort, förlag, år, upplaga, sidor
KTH Royal Institute of Technology, 2018. s. 89
Serie
TRITA-CBH-FOU ; 2018:38
Nyckelord
Rapeseed/canola straw, biorefinery, hemicelluloses, lignin, cellulose, cellulose nanoparticles, films, grafting, thermoplastic, biocomposites, rapshalm, bioraffinaderi, hemicellulosa, lignin, cellulosa, cellulosa nano partiklar, hemicellulosafilm, ympning, termoplastisk, biokompositer
Nationell ämneskategori
Polymerkemi
Forskningsämne
Fiber- och polymervetenskap
Identifikatorer
urn:nbn:se:kth:diva-234656 (URN)978-91-7729-913-4 (ISBN)
Disputation
2018-10-12, F3, Lindstedtsvägen 26, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20180912

Tillgänglig från: 2018-09-12 Skapad: 2018-09-07 Senast uppdaterad: 2018-09-12Bibliografiskt granskad

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Svärd, AntoniaBrännvall, ElisabetEdlund, Ulrica

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