PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 8, Number 1, 2022
molded pulp product (MPP) in the industry, it is important to fully understand how the manufacturing process is different from papermaking. One specific way to differentiate the processes is to compare their resulting products. As the paper industry uses several wood fibers with various pulping processes, it is interesting to compare some of these fibers, to further progress our understanding of the MPP process. In this study, six different wood fibers were used (as received) and analyzed to obtain the sample with the lowest moisture uptake and highest tensile properties. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and fiber analysis module (MorFi) observations were performed, as well as moisture uptake measurements after sorption and tensile tests. We observed significant differences between the fibers tested. Kraft fibers (bleached softwood kraft pulp (BSKP), bleached hardwood kraft pulp (BHKP), and unbleached softwood kraft pulp (USKP)) showed smoother surfaces and less non-cellulosic molecules, such as hemicellulose, lignin, and pectin, in the SEM images. Bleached chemi- thermomechanial pulp (BCTMP) and recycled pulps (R-NPM and R-CBB) both showed non-cellulosic molecules and rougher surfaces. These results were confirmed with the FTIR analysis. With kraft fibers, MPP mechanical properties were lower than non-kraft fibers. Resulting moisture uptake is in between the recycled fibers (lowest moisture uptake) and BCTMP (highest moisture uptake). The removal of non-cellulosic molecules reduces the mechanical properties of the resulting MPP. The incorporation of non-wood molecules, as found in recycled fibers, also reduces the mechanical properties, as well as moisture uptake, when compared with BCTMP. “ Tailoring nanofibrillated cellulose through sonication and its potential use in molded pulp packaging ”, Supattra Klayya, Nattaya Tawichai, Uraiwan Intatha, , Han Zhang, Emiliano Bilotti & Nattakan Soykeabkaew, Nanocomposites , Vol.7(1), (2021). Nanofibrillated cellulose (NFC) was systematically tailored by ultrasonic-assisted esterification with lactic acid at different amplitudes and times, which led to modified NFC (mNFC) with different degrees of substitution (DS), between 0.21 and 0.55, as confirmed by titration, FTIR, and C13 NMR. A partial fragmentation and decrease in crystallinity of mNFC were revealed by TEM and XRD. To form molded pulp sheets, 5 wt% mNFC was added into a bagasse (BG) pulp slurry, then partially dewatered before hot-pressed. mNFC worked effectively as self-retention aid, partly solving the issue of drainage during sheet forming as commonly observed from unmodified NFC. The BG/mNFC (DS 0.55) sheet exhibited an enhancement in tensile properties. Water resistance and barrier performance of the current sheets were also evidently increased. The results suggested that the higher DS on mNFC can improve water resistance and mechanical properties, simultaneously overcoming drainage challenges in processing of molded pulp products. NANO-SCIENCE “Techno -economic and environmental evaluation of a market pulp reinforced with micro- /nanofibers as a strengthening agent in packaging paper”, Ferran Serra - Parareda, Roberto Aguado, Sergi Arfelis, Ramon Xifré, Pere Fullana-i-Palmer & Marc Delgado-Aguilar, Journal of Cleaner Production, Vol.347, 1 May 2022, 131265. Partly inspired by the concept of masterbatch in plastics manufacturing, we developed a strategy to improve the technical viability, the economic feasibility, and the environmental performance of lignocellulosic micro-/nanofibers. Instead of investing strenuous efforts in dewatering and/or drying nanocellulose suspensions to maximize their consistency without significantly hampering redispersion, which still stands as an unresolved challenge, we used them in high proportions (up to 50 wt%) to reinforce a high-yield pulp. The suspension can be dewatered-pressed (0.70 – 1.75 MPa) to obtain wet laps of never-dried reinforced pulps, or dried to consistencies over 90% to produce dry boards, but at the cost
Technical Abstracts
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