| Author | Nguyen Thi Le Lien |
| Call Number | AIT Thesis no. PP-01-7 |
| Subject(s) | Waste paper--Recycling
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Paper recycling causes major changes in the strength properties of pulps. The magnitude of
change upon recycling is different for different types of pulps (mechanical, kraft, sulfite,
etc.).
Since mechanical pulps do not seem to suffer from the same problems as chemical (low
yield) pulps, difficulties in paper recycling seem to be related to the chemical composition
of free cell wall. It was concluded that the presence of lignin is a major obstacle for
extensive hydrogen bonding between microfibrils. Besides, hemicellulose has also been
proposed to play an important role on paper strength loss due to recycling. However, a
systematic work on these proposals is scarce and needs to be explored.
The present study was developed to examine the impact of chemical compositions of the
fiber wall on strength properties of recycled paper. Fine-free CTMP were used to remove
lignin, selectively at different degree, 15%, 35%, 45%, 50%, 70% and 90% respectively.
Delignified pulps were recycled and tested for tensile strength. The results show that
hemicellulose, which is unchanged in chlorite treatment, might not give any influences on
paper strength loss due to recycling.
It was concluded that elimination of lignin as low as 16% from the cell wall reduces
recycling potential of the fibers. This was proposed that the lignin should be removed first
from the surface of the fibers. Loss of surface lignin was discussed as a source of
hornification. |
| Year | 2001 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Pulp and Paper Technology (PP) |
| Chairperson(s) | Nazhad, Mousa M. |
| Examination Committee(s) | Retulainen, Elias ;Kolehmainen, Heikki ;Ruhanen, Mauno
|
| Scholarship Donor(s) | Swedish International Development Agency (Sida) |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |