Browsing by Author "Ashori, Alireza"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Effect of chitosan and cationic starch on the surface chemistry properties of bagasse paperPublication . Ashori, Alireza; Cordeiro, Nereida; Faria, Marisa; Hamzeh, YahyaThe use of non-wood fibers in the paper industry has been an economical and environmental necessity. The application of dry-strength agents has been a successful method to enhance the strength properties of paper. The experimental results evidencing the potential of chitosan and cationic starch utilization in bagasse paper subjected to hot water pre-extraction has been presented in this paper. The research analyzes the surface properties alterations due to these dry-strength agents. Inverse gas chromatography was used to evaluate the properties of surface chemistry of the papers namely the surface energy, active sites, surface area as well as the acidic/basic character. The results of the study revealed that the handsheets process causes surface arrangement and orientation of chemical groups, which induce a more hydrophobic and basic surface. The acid-base surface characteristics after the addition of dry-strength agents were the same as the bagasse handsheets with and without hot water pre-extraction. The results showed that the dry-strength agent acts as a protecting film or glaze on the surfaces of bagasse paper handsheets.
- Effects of hot water pre-extraction on surface properties of bagasse soda pulpPublication . Cordeiro, Nereida; Ashori, Alireza; Hamzeh, Yahya; Faria, MarisaIn this work, the effects of hot water pre-extraction of depithed bagasse on the soda pulping and surface properties were studied. The conditions of hot water pre-extraction were: maximum temperature 170 °C, heat-up time 90 min, time at maximum temperature 10 min, and solid to liquor ratio (S:L) 1:8. Consequently, the pre-extracted and un-extracted bagasse chips were subjected to soda pulping at 160 °C for 1h with 11, 14 and 17% active alkali charge and an S:L of 1:5. The results showed that the hot water pre-extraction increased bagasse surface texture porosity by hemicellulose degradation. Therefore, the delignification was faster for pulping of pre-extracted samples. At a certain charge of alkali, pre-extracted samples showed higher screened yield and lower Kappa number. For instance, at 17% alkali charge, pre-extracted bagasse gave 11.3% higher pulp yield compared with the un-extracted ones. Inverse gas chromatography (IGC) results showed that the hot water pre-extraction changed the active sites on the bagasse surface, decreasing the dispersive energy and the basicity character, and affected the particle morphology. The pulping process decreased the hydrophobicity and the basicity of the bagasse surface. The surfaces of un-extracted and pre-extracted bagasse pulps had similar properties but different morphology. The pulps present higher surface area and permeability with more reactive capacity.
- Influence of mild alkaline treatment on the cellulosic surfaces active sitesPublication . Ashori, Alireza; Ornelas, Mariana; Sheshmani, Shabnam; Cordeiro, NereidaAgro-residues fibers are inexpensive environmentally friendly alternatives to synthetic fibers in fiber reinforced polymer composites. The natural fiber properties and bondability with adhesive can be modified by subjecting the fibers to a pre-treatment procedure. The knowledge ofthe modified fibers sur face properties is essential to explain and predict their applications. The present study is focused on the effect of alkaline treatment on the surface characteristics of stalk fibers from rapeseed, tobacco, cotton, lemon balm and kiwi. The chemical composition of fibers and Fourier transform infrared spectroscopy show components extraction and the X-ray diffraction show improvement in the crystallinity index of the treated fibers. But only the IGC analysis allows us to know in detail the alterations on the fiber surface and the effect on the adhesion of the fibers. IGC shows that alkaline treatment produces changes in the nature and number of the active sites, responsible for the physico-chemical activity of the surface of the fibers. The fiber hydrophobicity was improved by the increase of more energetic and active sites in the surface. Also,the creation of new basic active sites and removal of acidic active sites from the fiber surface due to alkaline treatment has been clearly shown.
- Investigation on the surface properties of chemically modified natural fibers using inverse gas chromatographyPublication . Cordeiro, Nereida; Ornelas, Mariana; Ashori, Alireza; Sheshmani, Shabnam; Norouzi, HorThis paper presents the application of inverse gas chromatography (IGC) technique for characterization and comparison of the surface properties of the natural fibers as reinforcement fillers in wood plas tic composites. The effects of chemical modification using 1% NaOH were also studied. The fibers used for this work were Iranian cultivated eucalyptus, spruce, bagasse, and wheat straw. Chemical composi tion of fibers was found to be modified after treatment as characterized by Fourier transform infrared spectroscopy (FTIR). The crystallinity of fibers and the specific interaction was improved by the alkaline treatment, with more relevance to the agro-fibers. The IGC shows also a general increase in the wettability of the modified fiber when compared with the raw (unmodified) samples. Alkaline treatment achieves the best overall improvement in the properties evaluated of the agro-fibers when compared to the wood fibers.