湿热-压缩处理木材的纤维素晶体结构变化
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摘要
分别采用不同径向压缩率(25%和50%)并结合不同蒸汽处理温度(140、160℃和180℃)对人工林杉木(Cunninghamia lanceolata)进行湿热-压缩处理,然后利用X-射线衍射法(XRD)研究了湿热-压缩处理对木材纤维素微纤丝角、结晶度及微晶宽的影响规律。结果表明:湿热-压缩处理木材纤维素微纤丝角无明显变化,结晶度和微晶宽均增大。结晶度增幅介于28%~38%,不同压缩率和蒸汽处理温度对纤维素结晶度影响无显著差异。随着蒸汽处理温度的增加,微晶宽逐渐增大,在180℃蒸汽处理条件下达到最大值。
Compression combined with steam treatment to Chinese fir(Cunninghamia lanceolata)was carried out with different radial compression(compression ratio of 25% and 50%) in combination with different steam treatment temperatures(140,160 ℃ and 180 ℃).The variation of cellulose microfibril angle,crystallinity and crystallite width were characterized by X-ray diffraction(XRD).The results indicated that cellulose microfibril angle had no significant changes,however crystallinity and crystallite width were increased after CS-treatment.About 28%~38% increase of crystallinity was observed.Different compression ratios and steam treatment temperatures did not affect cellulose crystallinity significantly.With the increase of compression ratios,crystallite thickness increased gradually,the maximum value could be obtained when at 180 ℃.
Compression combined with steam treatment to Chinese fir(Cunninghamia lanceolata)was carried out with different radial compression(compression ratio of 25% and 50%) in combination with different steam treatment temperatures(140,160 ℃ and 180 ℃).The variation of cellulose microfibril angle,crystallinity and crystallite width were characterized by X-ray diffraction(XRD).The results indicated that cellulose microfibril angle had no significant changes,however crystallinity and crystallite width were increased after CS-treatment.About 28%~38% increase of crystallinity was observed.Different compression ratios and steam treatment temperatures did not affect cellulose crystallinity significantly.With the increase of compression ratios,crystallite thickness increased gradually,the maximum value could be obtained when at 180 ℃.
引文
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[6]Wei LQ,McDonald A G,Stark N M.Grafting of bacterial polyhydroxybutyrate(PHB)onto cellulose via in situ reactive extrusion with dicumyl peroxide[J].Biomacromolecules,2015,16(3):1040-1049.
[7]Donaldson L.Microfibril angle:Measurement,variation and relationships-A review[J].IAWA Journal,2008,29:345-386.
[8]Yin Y,Bian M,Song K,el al.Influence of microfibril angle on within—tree variations in the mechanical properties of Chinese fir(Cunninghamia lanceolata)['J].IAWA Journal,2011,32(4):431-442.
[9]Salmén L,Burgert I.Cell wall features with regard to mechanical performance.A review[J].Holzforschung,2009,63:121-129.
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[11]Tanahashi M,Goto T,Horii F,fit al.Characterization of steam-explosive wood ID:Transformation of cellulose crystals and changes of crystallinity[J].Mokuzai Gakkaishi,1989,35(7):554-662.
[12]唐晓淑.热处理变形固定过程中杉木压缩木材的主成分变化及化学应力松弛[D].北京:北京林业大学.2004.
[13]Navi P,Heger F.Combined densification and thermo-hydro-mechanical processing of wood[J].MRS Bulletin,2004,29(5):332-336.
[2]费本华.木材细胞壁力学性能表征技术及应用[M].北京:科学出版社,2014.
[3]Dwianto W,Morooka T,Norimoto M.Method for measuring viscoelastic properties of wood under high temperature and high pressure steam conditions[J].Journal of Wood Science,1999,45:373-377.
[4]Ito Y,Tanahashi M,Shigematsu M,et al.Compressive-molding of wood by high pressure steam-treatment:Part 2.Mechanism of permanent fixation[J].Holzforschung,1998,52:217-221.
[5]Hult E L,Iversen T,Sugiyama J.Characterization of the supermolecular structure of cellulose in wood pulp fibers[J].Cellulose,2003,10:103-110.
[6]Wei LQ,McDonald A G,Stark N M.Grafting of bacterial polyhydroxybutyrate(PHB)onto cellulose via in situ reactive extrusion with dicumyl peroxide[J].Biomacromolecules,2015,16(3):1040-1049.
[7]Donaldson L.Microfibril angle:Measurement,variation and relationships-A review[J].IAWA Journal,2008,29:345-386.
[8]Yin Y,Bian M,Song K,el al.Influence of microfibril angle on within—tree variations in the mechanical properties of Chinese fir(Cunninghamia lanceolata)['J].IAWA Journal,2011,32(4):431-442.
[9]Salmén L,Burgert I.Cell wall features with regard to mechanical performance.A review[J].Holzforschung,2009,63:121-129.
[10]江京辉.过热蒸汽处理柞木性质变化规律及机理研究[D].北京:中国林业科学研究院,2013.
[11]Tanahashi M,Goto T,Horii F,fit al.Characterization of steam-explosive wood ID:Transformation of cellulose crystals and changes of crystallinity[J].Mokuzai Gakkaishi,1989,35(7):554-662.
[12]唐晓淑.热处理变形固定过程中杉木压缩木材的主成分变化及化学应力松弛[D].北京:北京林业大学.2004.
[13]Navi P,Heger F.Combined densification and thermo-hydro-mechanical processing of wood[J].MRS Bulletin,2004,29(5):332-336.