Chinese non-wood pulps and potential of wheat straw pulp for making high quality paper | |
| Author | Fan, Li |
| Call Number | AIT Thesis no.PP-03-5 |
| Subject(s) | Papermaking--China Paper|xQuality--China |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science |
| Publisher | Asian Institute of Technology |
| Abstract | The non-wood fibre resources used in China paper industry was studied through literature review, mill visiting and industry people interview. Information shows that main non-wood species are suitable for producing fine paper grades, for they have slender and short fibre comparable to hardwood fibres. However, non-wood fibres are generally unevenly distributed, because of high percentage of non-fibre cells. Non-wood species usually contain less lignin and cellulose, but more hemicellulose, ash and extractives. Therefore, they behave differently to wood species during pulping, bleaching and paper making process. Unfortunately, the difference normally means more troubles. Wheat straw and rice straw are the most important non-wood fibre resources in quantity, but they are generally used only in low paper grades because of their characteristics and producing process. A favourable point of wheat straw pulp is that it has better recyclability. To extend the application of wheat straw pulp in high quality fine paper grades, the potential of upgrading wheat straw pulp by fractionation was studied in laboratory scale by Valmet pressure screen and Bauer McNett fractionationer. Results show that Statistics fractionation (by Bauer McNett fractionationer) has better effect than dynamic fractionation (Valmet pressure screen). It simply gives better separation effects. Namely less fines in long fractions (LF), low LF freeness etc. Fractionation has many good effects, such as reducing pulp freeness therefore reduce dewater time, improving dimensional stability potential, enhancing dryness after pressing etc, therefore it can enhance the WSP quality to some extent. However, fractionation has no effect or reverse effects on paper density, smoothness, tensile strength, formation and number of dirt spots. The refined LF wheat straw pulp (fractionated by Bauer McNett fractionationer) can compete with birch pulp in many aspects: It gives paper of higher light scattering coefficient, better z direction strength, better formation. Besides, less refining power is requirement in developing pulp strength. However, it showed wealmess like low tensile strength, worse dimensional stability and dirtiness. |
| Year | 2003 |
| 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) | Kolehmainen, Heikki |
| Examination Committee(s) | Malinen, Raimo;Viljakainen, Esa |
| Scholarship Donor(s) | Asian Development Bank |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2003 |