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Molecular Rheology of Coniferous Wood Tissues

 

作者: S. Chow,  

 

期刊: Transactions of the Society of Rheology  (AIP Available online 1973)
卷期: Volume 17, issue 1  

页码: 109-128

 

ISSN:0148-6055

 

年代: 1973

 

DOI:10.1122/1.549313

 

出版商: The Society of Rheology

 

数据来源: AIP

 

摘要:

The time‐dependent molecular motions were observed by infrared polarization technique for wood components strained parallel to the fiber axis. A two‐stage molecular motion involving three wood components, cellulose, hemicellulose, and lignin, is suggested as the course of wood molecular relaxation. The first stage begins at equilibrium, when a specimen is not stressed, and extends immediately to a minimum dichroic ratio(A⊥/A∥)of carbohydrate components represented by1160 cm−1(cellulose) and1730 cm−1(hemicellulose) bands, and the maximum dichroism of1500 cm−1(lignin). The second stage starts at the end of the first stage and extends to equilibrium recovery. Regardless of the form of external excitation (creep or stress relaxation), or the time of excitation (ramp‐ or step‐loading), the basic two‐stage molecular motion pattern was followed, while damping of the molecules accompanied the whole rheological process. The pattern of molecular motion for a wood component is a compensatory result of the interaction of all components. Removing one or more wood components changes the motion patterns of the remaining components. The response of cellulose in a specimen without the presence of lignin and hemicellulose is comparable to that of the other synthetic linear polymers.

 

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