PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL Volume 7, Number 3, 2021
CNF were added at increasing amounts (0%, 2%, 5%, 8% and 10%) to commercial Eucalyptus pulp to produce paper handsheet samples. Morphology, crystallinity, physical- mechanical and air barrier properties of the paper handsheets were evaluated. The results suggested that adding CNF has decreased the presence of empty spaces inside and on the surface of the paper handsheets by up to 61% due to the interaction between fibers and nanofibrils. The paper handsheets became denser, more compact and resistant to passage of air, as well as with greater mechanical performance with higher CNF content (10%). The bursting index is approximately 5 times higher on paper with addition of 10% of CNF compared to control paper handsheets. There were significant gains in the studied properties without any change in CNF/fibers surface charge or the use of any cationic polymer to assist the retention of nanofibrils and fibers. This study highlights the potential of CNF as additives in papermaking process, increasing its properties. NOVEL PRODUCTS “ On the role of fibre bonds on the elasticity of low-density papers: a micro- mechanical approach ”, L. Orgéas, P.J.J. Dumont, F. Martoïa, C. Marulier, S. Le Corre & D. Caillerie, Cellulose , Vol.28, pp.9919 – 9941 (2021). Fine prediction of the elastic properties of paper materials can now be obtained using sophisticated fibre scale numerical approaches. However, there is still a need, in particular for low-density papers, for simple and compact analytical models that enable the elastic properties of these papers to be estimated from the knowledge of various structural information about their fibres and their fibrous networks. For that purpose, we pursued the analysis carried out in Marulier et al. (Cellulose 22:1517 – 1539, 2015. https://doi.org/10.1007/s10570-015-0610-6) with low-density papers that were fabricated with planar random and orientated fibrous microstructures and different fibre contents. The fibrous microstructures of these papers were imaged using X-ray synchrotron microtomography. The corresponding 3D images revealed highly connected fibrous networks with small fibre bond areas. Furthermore, the evolutions of their Young’s moduli were non -linear and evolved as power-laws with the fibre content. Current analytical models of the literature do not capture these trends. In light of these experimental data, we developed a fibre network model for the in-plane elasticity of papers in which the main deformation mechanisms of the micromechanical model is the shear of the numerous fibre bonds and their vicinity, whereas the fibre parts far from these zones were considered as rigid bodies. The stiffness tensor of papers was then estimated both numerically using a discrete element code and analytically using additional assumptions. Both approaches nicely fit the experimental trends by adjusting a unique unknown micromechanical parameter, which is the shear stiffness of bonding zones. The estimate of this parameter is relevant in light of several recently reported experimental results. “ Bio-based materials for nonwovens ”, A.S. Santos, P.J.T. Ferreira & T. Maloney, Cellulose , Vol.28, pp.8939 – 8969 (2021). The nonwoven industry is one of the most innovative and important branches of the global fiber products industry. However, the use of petrochemical-based materials in many nonwoven products leads to severe environmental issues such as generation of microplastics. Synthetic material use in nonwovens is currently around 66%. This review covers potential technologies for the use of bio-based materials in nonwoven products. The current generation of nonwoven products relies heavily on the use of synthetic binders and fibers. These materials allow for products with high functional properties, such as permanence, strength, bulk, and haptic properties. The next generation of nonwoven products will have a higher fraction of natural and renewable materials as both binders and fiber elements. There are a wide range of materials under investigation in various nonwoven product categories. Especially,
Technical Abstracts
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