The use of atomic force microscopy as a tool to study the effect of a xylanase from Humicola grisea var. thermoidea in kraft pulp bleaching

2007 ◽  
Vol 40 (4) ◽  
pp. 723-731 ◽  
Author(s):  
Roseli G. Medeiros ◽  
Luciano P. Silva ◽  
Ricardo B. Azevedo ◽  
Francides G. Silva ◽  
Edivaldo Ximenes F. Filho
Keyword(s):  
Atomic Force Microscopy ◽  
Kraft Pulp ◽  
Pulp Bleaching ◽  
Force Microscopy ◽  
Atomic Force ◽  
Kraft Pulp Bleaching ◽  
Humicola Grisea

Ultrastructural changes in a holocellulose pulp revealed by enzymes, thermoporosimetry and atomic force microscopy

Holzforschung ◽  
2005 ◽  
Vol 59 (6) ◽  
pp. 589-597 ◽  
Author(s):  
Jesper Fahlén ◽  
Lennart Salmén
Keyword(s):  
Atomic Force Microscopy ◽  
Kraft Pulp ◽  
Enzymatic Treatment ◽  
Ultrastructural Changes ◽  
Cellulose Fibril ◽  
Force Microscopy ◽  
Fibre Wall ◽  
Atomic Force ◽  
Pulp Fibres ◽  
Fibril Aggregates

Abstract To increase our knowledge of the ultrastructure within softwood fibres, enzymatic treatment, thermoporosimetry, light microscopy, and atomic force microscopy with image analysis were used to investigate the structure of holocellulose softwood pulp fibres. The size of the average cellulose fibril aggregates and the width of pore and matrix lamellae were found to be uniform across the secondary cell-wall layer in the transverse direction of the wood fibre wall. In holocellulose, these dimensions were very similar to those in the native wood, whereas in kraft pulp the cellulose fibril aggregates were larger and the pore and matrix lamellae broader. These differences between holocellulose and kraft pulp fibres suggest that a high temperature is needed for cellulose fibril aggregation to occur. Neither refining nor drying of the holocellulose pulp changed the cellulose fibril aggregate size. Upon drying and enzymatic treatment, a small decrease in the pore and matrix lamella width was evident throughout the fibre wall. This indicated not only uniform distribution of pores throughout the fibre wall, but also enzymatic accessibility to the entire fibre wall. The holocellulose pulp had a somewhat larger pore volume than the kraft pulp. Refining of the holocellulose pulp led to pore closure, probably due to increased mobility of the fibre wall. The enzymatic treatment revealed that during hydrolysis of one hemicellulose, part of the other was also dissolved, indicating that the two hemicelluloses are to some extent linked to each other in the structure.

Analysis of precipitated lignin on kraft pulp fibers using atomic force microscopy

Cellulose ◽  
2012 ◽  
Vol 19 (3) ◽  
pp. 1013-1021 ◽  
Author(s):  
Franz J. Schmied ◽  
Christian Teichert ◽  
Lisbeth Kappel ◽  
Ulrich Hirn ◽  
Robert Schennach
Keyword(s):  
Atomic Force Microscopy ◽  
Kraft Pulp ◽  
Pulp Fibers ◽  
Force Microscopy ◽  
Atomic Force

Alkaline peroxide treatment of ECF bleached softwood kraft pulps: Part 2. Effect of increased fiber charge on refining, wet-end application, and hornification

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Zheng Dang ◽  
Thomas Elder ◽  
Jeffery S. Hsieh ◽  
Arthur J. Ragauskas
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Morphology ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Cationic Starch ◽  
Force Microscopy ◽  
Tensile Index ◽  
Alkaline Peroxide ◽  
Atomic Force ◽  
Starch Adsorption

Abstract The effect of increased fiber charge on refining, cationic starch adsorption, and hornification was examined. Two pulps were investigated: (1) a softwood (SW) kraft pulp (KP) which was bleached elementally chlorine-free (ECF) and served as control; and (2) a control pulp treated with alkaline peroxide, which had a higher fiber charge. It was shown that increased fiber charge can improve the efficiency of the refining treatment, as indicated by differences in tensile index refined from 0 to 1000 revolutions. When the control pulp was refined from 4000 to 8000 revolutions, the tensile index decreased. In contrast, the tensile index of the higher fiber charge pulp (HCP) was higher under the same refining conditions. Upon addition of 2% cationic starch to both pulps, the tensile index of the control pulp increased by 13.7% and that of HCP by 23.7%. Atomic force microscopy did not reveal differences in the surface morphology of the two pulps with and without cationic starch adsorption. Peroxide treatment enhanced the fiber charge of the never-dried pulp. This was beneficial in reducing hornification when pulp was dried at 105°C. However, if the once dried pulp at 105°C was treated with peroxide, this resulted in a drastic decrease in intrinsic viscosity of the pulp and lower tensile and burst indices of the test sheets.

Electrostatic Forces on the Surface of Metals as Measured by Atomic Force Microscopy

2000 ◽  
Vol 10 (1-2) ◽  
pp. 15
Author(s):  
Eugene Sprague ◽  
Julio C. Palmaz ◽  
Cristina Simon ◽  
Aaron Watson
Keyword(s):  
Atomic Force Microscopy ◽  
Electrostatic Forces ◽  
Force Microscopy ◽  
Atomic Force
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