ACS Sustainable Chemistry & Engineering
pubs.acs.org/journal/ascecg
Research Article
Figure 7. (A) System boundary for cradle-to-gate analysis of the EFB/hairy cellulose fiber nonwoven. (B) The ReCiPe 2016 LCA results for the productions of the EFB/hairy cellulose fiber nonwoven containing 10 wt % hairy cellulose fiber refined for 30 min and a polyester air filter. “Others” includes transport of EFB from collection to the factory of nonwoven, water, and wastewater. The illustrations in A were created with BioRender.
acts as a plasticizer, penetrating the disordered regions of the cellulose fibrils and disrupting hydrogen bonds, reducing stiffness and restoring flexibility. 61,62 Additionally, the (hairy) cellulose fibers also contain hemicellulose, which is even more hygroscopic due to its branched and amorphous structure. 46 At a higher (hairy) cellulose fiber loading of 20 and 30 wt %, the deformation force required to deform the steam-rewetted EFB/cellulose fiber nonwoven using unrefined cellulose fiber as the binder was measured to be 26.7 and 41.9 N, respectively, corresponding to R − 1 of 0.094 and 0.098 mm − 1 . However, deforming EFB/hairy cellulose fiber nonwovens at such high binder loading was not achievable, and visible warpage (see Figure 5C,D for the exemplarily images), characterized by uneven deformation and the inability to conform to the curved base during the deformation experiment, 63 can be observed. This behavior is attributed to the higher degree of hornification (irreversible hydrogen bonding) of the hairy cellulose fibers. The water retention value of once-dried (hairy) cellulose fibers was found to be 0.91 g/g for unrefined cellulose fibers
decreasing to 0.82, 0.77, and 0.65 g/g for hairy cellulose fibers refined for 10, 20, and 30 min, respectively, which is the opposite of the trend observed in the never-dried condition. In addition to the deformation experiment, it is worth mentioning that EFB/hairy cellulose fiber nonwovens containing 10 wt % hairy cellulose fibers can be molded into practical shapes, such as a face mask (Figure 5E, left) and even more complex geometries with high curvature (Figure 5F), using either the never-dried approach or the steam-rewetted approach. 2.6. Performance Differences of EFB/(Hairy) Cellulose Fiber Nonwovens as-Molded and Remolded Using the Steam-Rewetting Approach. It can be expected that the properties of EFB/(hairy) cellulose fiber nonwovens molded using the never-dried approach should follow closely that of those reported in Section 2.4. However, the properties of rigid EFB/(hairy) cellulose fiber nonwovens remolded using the steam-rewetting approach may differ from those previously measured due to the change in the structure of the (hairy) cellulose fiber network used as the binder. To investigate this
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https://doi.org/10.1021/acssuschemeng.5c00041 ACS Sustainable Chem. Eng. 2025, 13, 6209 − 6221
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