PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL Volume 6, Number 1, 2020
and wet), were measured and compared. Characterization of morphological and chemical properties of tissue handsheets was conducted with SEM and time-of-flight-secondary ion mass spectrometry (ToF-SIMS). The combined kraft pulped hardwood and autohydrolyzed hemp pulp fibers displayed improvements in tensile index, burst resistance, and softness of tissue handsheets compared to only kraft hardwood pulp handsheets without adversely impacting water absorption. Hardwood fibers showed a sparse distribution of surface lignin compared to hemp fibers using the same defibration. This technology can lead to a variety of eco-friendly tissue paper products that are not only highly energy efficient, but avoid harsh chemical processing. Effect of hydrogen peroxide bleaching on anionic groups and structures of sulfonated chemo-mechanical pulp fibers, Mingfu Lia et al, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol.585 . The properties of the chemo- mechanical pulp were determined by the position and quantity of anionic groups in the pulp fibers. In this study, the effects of anion group content and structure in sulfonated mulberry stem chemo-mechanical pulp (SCMP) were investigated during the hydrogen peroxide (H2O2) bleaching process. Surface morphology and anion group structure of the pulp fibers were analyzed by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and gas chromatography-mass spectrometry (GCMS). The results indicate that the sulfonic group content in bleached pulp decreases with the concentration of H2O2 to a minimum content of 71.53 μmol g−1, which is reduced by 22.68% in comparison to the unbleached pulp content of 92.51 μmol g−1. The content of carboxyl groups in pulp first increases and then decreases with the concentration of H2O2. The maximum carboxyl group content is 164.79 μmol g−1, which is increased by 53.97% compared with unbleached pulp at 107.03 μmol g−1. The total anion groups content of SCMP first increases and then decreases with the concentration of H2O2. FTIR and XPS analysis show that the content of anion groups on the surface of the pulp fibers increases slightly after H2O2 bleaching. GCMS analysis demonstrates that the content of uronic acid increases after H2O2 bleaching and the order of increase is 4-O- MeGlcA > GlcA > GalA. The contents of sulfonic acid group, total anion groups (TAGs) and surface anion groups (SAGs) of bleached pulp increase because of the hydroxyl group oxidation, terminal group reduction, methyl esterification of pectin and decomposition of polyxylose, resulting in the formation of new carboxyl groups and more uronic acid. This study reveals the mechanism of the effect of hydrogen peroxide bleaching on the anionic groups in the SCMP pulp, which is conducive to the development of bleaching technology for high yields of mulberry stem pulp. MCDM approach for selection of raw material in pulp and papermaking industry, Meenu Singh et al, Materials and Manufacturing Processes, Vol.35(3) . Selection of a suitable fibrous raw material for the pulp and papermaking industries is a tedious process involving a lot of experimental procedures. This process can be reduced to some extent through computer-based simulation tools and treating the problem as a multi-criteria decision making (MCDM) problem. In the present study, selection of fibrous raw material is treated as an MCDM problem where chemical, morphological and physical properties of the fibers are considered as different criteria and study is done in context of Indian Pulp and Paper Mills. TOPSIS, its fuzzy variant (FTOPSIS) and its modified variant (MTOPSIS) are employed to identify the suitable selection of fibers. The results obtained by these methods when discussed with experts indicate that MCDM tools like TOPSIS (and its variants) can be an attractive alternative for simulation-based selection of fibrous raw material for pulp and paper industries.
Technical Abstracts
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