Showing posts with label cellulose. Show all posts
Showing posts with label cellulose. Show all posts

20 April 2010

Article: Hydrolysis of cellulose in cotton-based paper (2008)


Title: Hydrolysis of the amorphous cellulose in cotton-based paper

Author
: Catherine H. Stephens, Paul M. Whitmore, Hannah R. Morris, and Mark E. Bier

Reference
: Biomacromolecules 9 (4), 2008, 1093-1099

Link
: http://www.cmu.edu/... (pdf, 266 Kb)


Abstract
:
Hydrolysis of cellulose in Whatman no. 42 cotton-based paper was studied using gel permeation chromatography (GPC), electrospray ionization-mass spectrometry (ESI-MS), and uniaxial tensile testing to understand the course and kinetics of the reaction. GPC results suggested that scission reactions passed through three stages. Additionally, the evolution of soluble oligomers in the ESI-MS data and the steady course of strength loss showed that the hydrolysis reaction occurred at a constant rate. These findings are explained with a more detailed description of the cellulose hydrolysis, which includes multiple chain scissions on amorphous segments. The breaks occur with increasing frequency near the ends of amorphous segments, where chains protrude from crystalline domains. Oligomers unattached to crystalline domains are eventually created. Late-stage reactions near the ends of amorphous segments produce a kinetic behavior that falsely suggests that hydrolysis had ceased. Monte Carlo simulations of cellulose degradation corroborated the experimental findings.


Article: calcium washing treatments on paper (2001)


Title: Effects of dilute calcium washing treatments on paper
Author: John Bogaard, and Paul M. Whitmore
Reference: Journal of the American Institute for Conservation 40, 2001, 105-123
Link: http://www.cmu.edu/... (pdf, 1.03 Mb)

Abstract:
Dilute aqueous solutions of three different calcium salts have been compared for their effectiveness as wash treatments for stabilizing the cellulose of paper objects. Treated paper samples were evaluated for chemical changes resulting from the treatment and from subsequent accelerated thermal aging. The extent of alkaline damage of the treated sheets was found to be insignificant even for photo-oxidized papers. The treatments slowed the deterioration of the paper during thermal aging, but eventually the protective benefit weakened. Neutralization of acid in the sheets had a greater stabilizing effect on the paper than did the presence of calcium. Dilute alkaline calcium washes were less effective in retarding degradation of photo-oxidized papers than the same washes of unoxidized sheets. Chemical reduction of the photo-oxidized paper followed by washing with the dilute alkaline calcium solution was very effective at slowing its deterioration during thermal aging. Treatment with the dilute alkaline calcium solution also slowed photo-oxidation of paper during exposure to near-ultraviolet radiation.

30 November 2008

Evaluation of Cellulose Ethers for Conservation (1990)


Title: Evaluation of Cellulose Ethers for Conservation

Author: Robert L. Feller and M. Wilt
Publisher: The Getty Conservation Institute
Year: 1990
Pages: 165
Format: PDF (2.1 Mb)
Link: http://www.getty.edu/...

Table of contents:

Chapter 1. Introduction
Chapter 2. Properties of Cellulose Ethers
Chapter 3. Standards of Stability
Chapter 4. Summary of Previous Investigation Supported by the National Museum Act
Chapter 5. Description of Materials and Experimental Procedures
Chapter 6. Results and Discussion
Chapter 7. Conclusions
Appendices

Cellulose Nitrate in Conservation

Title: Cellulose Nitrate in Conservation
Author: Charles Selwitz
Publisher: The Getty Conservation Institute
Year: 1988
Pages: 71
Format: PDF (556 Kb)
Link: http://www.getty.edu/...

Table of contents:

Chapter 1. The Use of Cellulose Nitrate in Art Conservation
Chapter 2. The Structural Chemistry of Commercial Cellulose Nitrate
Chapter 3. Causes of Instability
Chapter 4. Cellulose Nitrate Stability at Ambient Conditions
Chapter 5. The Use of Cellulose Nitrate as an Adhesive for Ceramics
Chapter 6. The Use of Cellulose Nitrate as a Metals Coating
Appendix. Proprietary Material Cited in the Text

24 November 2008

Washing of Cellulose Films (2004)

Title: Effect of Washing of Cellulose Triacetate Films with Different Degrees of Degradation
Author: Karin Bonde Johansen
Type of Document: Master thesis
University: School of Conservation, The Royal Danish Academy of Fine Arts
Year: 2004
Pages: 116
Download: http://www.dfi.dk/... (PDF, 3.67 Mb)

Table of contents (compact version):

1. Introduction
2. Background
3. Test methods
4. Experiments
5. Results
6. Comments and discussions
7. Perspectives
8. Conclusion
9. References