TY - JOUR
T1 - Effects of pressurized hot water extraction on the nanoscale structure of birch sawdust
AU - Penttilä, Paavo A.
AU - Kilpeläinen, Petri
AU - Tolonen, Lasse
AU - Suuronen, Jussi Petteri
AU - Sixta, Herbert
AU - Willför, Stefan
AU - Serimaa, Ritva
N1 - Funding Information:
Acknowledgments University of Helsinki Research Funds is acknowledged for financial support.
Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/10
Y1 - 2013/10
N2 - Pressurized hot water extraction with a flow-through system was used to extract hemicelluloses and lignin from birch sawdust. The structure of the extraction residue was studied on various levels. Molecular mass distributions were determined with gel permeation chromatography and the crystal structure of cellulose was characterized using wide-angle X-ray scattering (WAXS). Information on the short-range order of cellulose microfibrils and on the nanoscale pore structure was obtained with small-angle X-ray scattering (SAXS), and the micrometre scale cellular morphology was imaged with X-ray microtomography. The pressurized hot water treatment was observed to increase the lateral width of cellulose crystallites, determined with WAXS, whereas a possible small decrease in the crystallinity of cellulose compared to native wood was detected. The molecular mass of cellulose remained at a relatively high level. According to the SAXS results, a tighter lateral association of cellulose microfibrils was observed in the extracted samples, which possibly led to opening of pores between bundles of microfibrils, as indicated by an increased specific surface area. A reduction in the thickness of the fibre cell walls was evidenced by X-ray microtomography.
AB - Pressurized hot water extraction with a flow-through system was used to extract hemicelluloses and lignin from birch sawdust. The structure of the extraction residue was studied on various levels. Molecular mass distributions were determined with gel permeation chromatography and the crystal structure of cellulose was characterized using wide-angle X-ray scattering (WAXS). Information on the short-range order of cellulose microfibrils and on the nanoscale pore structure was obtained with small-angle X-ray scattering (SAXS), and the micrometre scale cellular morphology was imaged with X-ray microtomography. The pressurized hot water treatment was observed to increase the lateral width of cellulose crystallites, determined with WAXS, whereas a possible small decrease in the crystallinity of cellulose compared to native wood was detected. The molecular mass of cellulose remained at a relatively high level. According to the SAXS results, a tighter lateral association of cellulose microfibrils was observed in the extracted samples, which possibly led to opening of pores between bundles of microfibrils, as indicated by an increased specific surface area. A reduction in the thickness of the fibre cell walls was evidenced by X-ray microtomography.
KW - Birch
KW - Cellulose crystallinity
KW - Hydrothermal treatment
KW - Pressurized hot water extraction
KW - X-ray scattering
UR - http://www.scopus.com/inward/record.url?scp=84884418126&partnerID=8YFLogxK
U2 - 10.1007/s10570-013-0001-9
DO - 10.1007/s10570-013-0001-9
M3 - Article
AN - SCOPUS:84884418126
SN - 0969-0239
VL - 20
SP - 2335
EP - 2347
JO - Cellulose
JF - Cellulose
IS - 5
ER -