Potential of raffia nanofibrillated cellulose as a reinforcement in extruded earth-based materials

Dimensional stability, durability and performance of hybrid recycled cellulose fibres reinforcing earth-based materials

“…12 X-ray diffraction (XRD) was carried out using a Rigaku MiniFlex 600 with a range of 10°–70° (2Ɵ) at a speed of 0.02°/min and the results showed the mineral composition of 55% Quartz, 34% Microcline and 11% Kaolinite. 41 The soil specific gravity was 2.76 and the previous study 16 on this soil reported that the plastic limit and the liquid limit were respectively 24.9% and 42.4% with a plasticity index of 17.5%. The soil was classified as CL (inorganic clays of low plasticity) according to the unified soil classification system (USCS).…”

“…Furthermore, the slight reduction in water absorption capacity coupled with the increase in composite density due to the replacement of CP by CNF may be related to the ability of the CNF to fill the pores due to their nanoscale. 41 The density change of this hybrid composite may be due to the combined effects of different microstructural parameters such as the packing density of the nanofibres, their specific surface area and the packing density of the particles (clay soil + Portland cement) that occur during the extrusion process. 35 Although the water absorption of the soil-based composites increases after the inclusion of cellulose fibre, their average values are less than 37% (Figure 5), in line with the acceptable value suggested by NBR 5640.…”

“…The results reveal that the inclusion of CNF in concrete materials (i) promotes the formation of C-S-H, the modification of the pore structure and interface characteristics, (ii) increases the density and thus improves the strength of the concrete. Recently, Stanislas et al 41 demonstrated that the inclusion of up to 0.5 wt% of raffia CNF in earth-based materials significantly increased the flexural strength and drying shrinkage of the composite, while thermal conductivity and bulk density increased slightly. However, unlike CNF-reinforced earth bricks, which still exhibit brittle behaviour, 38,41 the inclusion of CP in the earth matrix 12,13 significantly increases its ductility and toughness while reducing thermal conductivity and bulk density.…”

“…Recently, Stanislas et al 41 demonstrated that the inclusion of up to 0.5 wt% of raffia CNF in earth-based materials significantly increased the flexural strength and drying shrinkage of the composite, while thermal conductivity and bulk density increased slightly. However, unlike CNF-reinforced earth bricks, which still exhibit brittle behaviour, 38,41 the inclusion of CP in the earth matrix 12,13 significantly increases its ductility and toughness while reducing thermal conductivity and bulk density. This suggests the use of both cellulose-based materials (CNF and CP) as reinforcing agents in an earth-based matrix in order to assess their ability to bridge nanoscale and microscale cracks as well as improve the packing density of the hybrid composite.…”

Nanocellulose-based membrane as a potential material for high performance biodegradable aerosol respirators for SARS-CoV-2 prevention: a review

“…Nanocellulose-based filter media, which could replace petroleum-based masks and respirators (FFP2 or FFP3 for European Standards and N95 or N99 for US standards) in the filtration of airborne viruses, have been intensively developed recently around the world as an environmentally friendly solution (Liu et al 2021a , b ; Ukkola et al 2021 ; Wang et al 2019b). The preparation of cellulose nanofibrils (CNF) from cellulosic materials has several advantages such as high specific surface area, easy functionalization and high mechanical strength (Correia et al 2016 ; Stanislas et al 2022 , 2020 ; Xiong et al 2021 ), which improves the capture efficiency of small particles due to the nanoscale of the pores (Ukkola et al 2021 ). Recently, CNF have been used to prepare filter media by the freeze-drying method for face masks (Mao et al 2008 ; Segetin et al 2007 ; Sim and Youn 2016 ; Ukkola et al 2021 ), water decontamination (Sehaqui et al 2016 ; Wang et al 2020 ), battery separator (Sim et al 2015 ), coating layers (Bai et al 2019 ), transparent devices (Wang et al 2020 ) and vehicle exhaust treatment (Liu et al 2021a , b ), as shown in Table 5 .…”