Jafar Ebrahimpour Kasmani; Ahmad Samariha; Alireza Khakifirooz
Abstract
This study aimed to investigate the use of cellulose nanofibers and starch-nano-cellulose and polyacrylamide-nano-cellulose hybrid systems for the replacement of imported long chemical fibers in the production of these papers. In this study, imported long fiber chemical pulp was added to cotton pulp ...
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This study aimed to investigate the use of cellulose nanofibers and starch-nano-cellulose and polyacrylamide-nano-cellulose hybrid systems for the replacement of imported long chemical fibers in the production of these papers. In this study, imported long fiber chemical pulp was added to cotton pulp at 4 levels. Cellulose nanofibers were added to cotton pulp at a 5% level with 1% starch and 0.1% with polyacrylamide. Three levels of cationic starch and three levels of cationic polyacrylamide were also used. From each of the treatments, 60 gm-2 handsheet were made finally the physical, mechanical and optical properties of the paper made from different pulps were compared. The results showed that with increasing nanocellulose individually, compared to imported long fibers, surface smoothness, tensile strength, bursting, tearing of paper increased and air resistance, folding resistance and opacity decreased. Increasing nanocellulose in combination with cationic polyacrylamide increased the paper air resistance and surface area, tensile, burst, tear, and folding strength of the paper compared to imported long fibers, air resistance and opacity. With the increase of nanocellulose in combination with cationic starch, as compared to imported long fibers, surface smoothness, tensile strength, bursting, folding increased but opacity decreased. FE-SEM results also showed that with increasing percentage of cellulose nanofibers, the pores decreased significantly. As a result of the addition of 5% cellulose nanofibers the surface of the paper became smoother and the pores were filled relatively, confirming the results of surface smoothness and air resistance.
Management and Economics wood
Eiraj Mansoryar; Alinaghi Karimi; Ghanbar Ebrahimi; Ahmad Mirshokraei; Sohrab Rahimi
Abstract
The water repellency and dimensional stabilization of wood species are important for outdoor uses. In this study, the water absorption and water repelling of poplar wood (Populus Alba) by emulsion of paraffin, Quaternary ammonium and starch, were investigated. Paraffin in three levels of 0%, 3%, 5%, ...
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The water repellency and dimensional stabilization of wood species are important for outdoor uses. In this study, the water absorption and water repelling of poplar wood (Populus Alba) by emulsion of paraffin, Quaternary ammonium and starch, were investigated. Paraffin in three levels of 0%, 3%, 5%, Quaternary ammonium in three levels of 0%, 1.5%, 2.5% and also starch in three levels of 0%, 1% and 2%(by weight) were selected as variables. A set of matched specimens were set aside as control, for making comparison. Results showed that the amount of paraffin had a positive significant effect on water absorption and water repellency that is increasing paraffin would improve these properties. Furthermore, specimens treated with paraffin had better water repellency than control samples. Based on the results, it is claimed that the treatment of 5% paraffin, 0-1.5% Quaternary ammonium and 0-1% starch will bring about water absorption and water repellency in treated specimens to a desired level, without causing any damage to other physical properties of them.
Pulp and paper
Hamid reza Rodi; Haseibeh Saeedi; Kermanian Hossein
Abstract
Improvement the strength properties of papers made from recycled fibers is of important aims in papermaking industries. Current researches revealed that higher retention of strength induced additives through alternative absorption of polymers having opposite charge is one of promising approaches to obtain ...
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Improvement the strength properties of papers made from recycled fibers is of important aims in papermaking industries. Current researches revealed that higher retention of strength induced additives through alternative absorption of polymers having opposite charge is one of promising approaches to obtain such purpose. In this study, treatment of fibers prepared from neutral sulfite semi-chemical papers with cationic starch and anionic CMC was conducted in pH~7, pH~10 and 0.001 M NaCl salty suspension. Then, fibers water retention value and zeta potential was measured. Standard handsheets with 60±3 g/m2 basis weight were made from untreated and treated pulps. The results have shown that fibers WRV significantly increased by absorbing of these two water-loving polymers. Consecutive changes of zeta potential confirmed charge reversion of fibers surface and sequential absorption of couple polymers. Scanning electron micrographs prepared from the samples of untreated and treated papers presented new variations in amount of fibers bend area due to the larger absorption of these two reinforcement polymers. Moreover, considerable development in paper mechanical characteristics (tensile, burst and tear indices) proved the success of high absorption of applied bio-polymers.
Physics and anatomy
Vahid Safdari
Abstract
Understanding of many wood technological features depends on anatomical characteristics which, unfortunately, researchers in Iran have not focused on recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut with unstudied woody anatomical features. We studied one ...
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Understanding of many wood technological features depends on anatomical characteristics which, unfortunately, researchers in Iran have not focused on recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut with unstudied woody anatomical features. We studied one of these species, Calligonum comosum (Polygonaceae). Three mature shrubs were selected and small cubic samples of woody stem and root were taken. Micro-sections were obtained with micro-tome and after dying with Astra-blue and Safranin the sections were mounted in Canada balsam. The results showed that many differences between roots and stems exist, such as distinct growth rings in the stems and indistinct rings in the roots, the presence of gums in the stems and absence in the roots, and lower ray width of the stems compared to the roots, inherent characteristics that have been reported by many other researchers. The most important difference between Calligonum comosum’s roots and stems is parenchyma-like fibers in the thin-walled roots which cannot be distinguished from axial parenchyma. The ground tissue of woody roots is parenchymatous cells full of starches, which probably can be related to the drought situation of deserts. The bark of Calligonum comosum has priderm and sclereid cells which make the bark stiff and hard. Also the result of particleboard of fabricated of Calligonum comosum’s wood showed that boards has at least technical characteristics of European Standard EN 312 and hence the silviculture of this species for stooping of erosion of soil and is suitable species for desertification and its wood can be used for producing of wood based panel.
