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Two types of cellulose nanofibrils (CNFs) were isolated from cotton linter fibers and hardwood fibers through mechanical fibrillation methods. The dialdehyde cellulose nanofibrils (DACNFs) were prepared through the periodate oxidation method, and their morphological and structural properties were investigated. The characteristics of the DACNFs during the concentration process were also explored. The AFM analysis results showed that the mean diameters of wood fiber-based CNFs and cotton fiber-based CNFs were about 52.03 nm and 69.51 nm, respectively. However, the periodate oxidation treatment process obviously reduced the nanofibril size and destroyed the crystalline region of the nanofibrils. Due to the high crystallinity of cotton fibers, the cotton fiber-based DACNFs exhibited a lower aldehyde content and suspension stability compared to the wood fiber-based DACNFs. For the concentration process of the DACNF suspension, the bound water content of the concentrated cotton fiber-based DACNFs was lowered to 0.41 g/g, which indicated that the cotton fiber-based DACNFs could have good redispersibility. Both the wood fiber-based and cotton fiber-based DACNF films showed relatively good transmittance and mechanical strength. In addition, to the cotton fiber-based DACNF films had a very low swelling ratio, and the barrier water vapor and oxygen properties of the redispersed cotton fiber-based DACNF films decreased by very little. In sum, this study has demonstrated that cotton fibers could serve as an effective alternative to wood fibers for preparing CNFs, and that cotton fiber-based DACNFs have huge application prospects in the field of packaging film materials due to their stable properties during the concentration process. [ABSTRACT FROM AUTHOR]

This study aims to investigate the relationship between mechanical fibrillation, morphological properties, and rheological behavior of cellulosic fiber. Three types of cellulosic fibers were obtained by adjusting mechanical fibrillation, namely squashed cellulose, incompletely nanofibrillated cellulose, and completely nanofibrillated cellulose, respectively. The squashed cellulose with large size and small aspect ratio had low entanglement capacity, thus forming a weak fiber network. The corresponding suspension exhibited low viscosity, weak elastic behavior, small yield stress, and low dynamic stability. An obviously increasing aspect ratio and entanglement capacity were observed with increasing mechanical fibrillation, resulting in entangled fiber network structure. Hence, the cellulosic fiber suspension obtained by more mechanical fibrillation exhibited higher viscosity, stronger gel-like behavior, and bigger yield stress. Moreover, the extremely entangled fiber network structure has better anti-deformation capacity and recovery capacity. We revealed the fundamental insights into the relationship between morphologies and rheological properties of cellulosic fiber, paving the way for designing cellulose-based materials. [ABSTRACT FROM AUTHOR]

Industrial emissions and oil spills as worldwide challenges have induced severe pollution and threatened the ecological environment. Conventionally, superhydrophobic surfaces show underwater lipophilicity, whereas superhydrophilic surfaces exhibit underwater oleophobicity. However, the intrinsic characteristics of these materials limit their practical applications for dealing with industrial oily wastewater. Here, from a chemical point of view, a lignocellulosic fiber surface with superwetting characteristics was successfully fabricated by the strategically adjusted condensation reaction of melamine and formaldehyde, making it underoil superhydrophobic and underwater superoleophobic. The formation of the dual superlyophobic surface in oil/water systems was related to the surface topography and the essential chemistry of the modified lignocellulosic fibers. After being pre-wetted by water, the dual superlyophobic melamine formaldehyde lignocellulosic (DSMFL) fibers were able to separate a light-oil/water mixture by gravity filtration. Simultaneously, the DSMFL fibers were sufficient to separate a heavy-oil/water mixture when they were pre-wetted by a heavy oil under a gravity-driven mechanism. In addition, the DSMFL fibers still showed excellent dual superlyophobicity along with robust chemical stability and had high separation efficiencies for dichloroethane (DCE)/water or kerosene/water mixtures after 50 separation cycles. The effective absorption of the light oil on the upper layer of the aqueous phase exceeded 1000%. Finally, the DSMFL fibers could be degraded into a nitrogen source for plant growth. [ABSTRACT FROM AUTHOR]

This work aimed to study the stabilization mechanism induced by different morphologies of cellulosic fiber in O/W emulsion. Three types of cellulosic fibers were named squashed cellulose, incompletely nanofibrillated cellulose, and completely nanofibrillated cellulose, respectively. Squashed cellulose acted as barriers between the droplets to stabilize emulsion via depletion flocculation, whereas incompletely nanofibrillated and completely nanofibrillated cellulose formed covering layer via interfacial adsorption and connected adjacent droplets to create the droplet-fiber network structure via bridging flocculation. Differently, completely nanofibrillated cellulose formed the denser covering layer leading to a more stability of droplet. Importantly, it had the higher capacity of bridging flocculation, which can tightly connect the adjacent droplets to form a stronger droplet-fiber 3D network structure. Consequently, in rheological analysis including creep compliance, and dynamic modulus, the corresponding emulsions showed excellent anti-deformation ability and dynamic stability. This study provides practical guidance on the productions of foodstuff and cosmetic. • Different morphologies of cellulosic fiber obtained by mechanical fibrillation. • Squashed cellulose stabilized Pickering emulsions by depletion flocculation. • Interfacial adsorption and bridging flocculation formed droplet-fiber 3D structure. • Rheological properties revealed the interaction between droplets and cellulose. [ABSTRACT FROM AUTHOR]

• 76.96% DP reduction was achieved after treatment by recycled endoglucanase. • Competitive adsorption existed between recycled and fresh endoglucanase. • More fibers were degraded to saccharides when fresh endoglucanase was added. Enzymatic pretreatment as an eco-friendly strategy has offered potential benefits in disintegrating cellulosic fibers into fibrils but limited by its high price. In this study, endoglucanase recycling was investigated in order to reduce endoglucanase expanses. Significant DP reduction can be achieved from 50.88% to 76.96% only by recycling liquid which included free endoglucanase. In the presence of fresh endoglucanase, no more pronounced reduction of DP was observed in all recycling rounds attributing to competitive adsorption between fresh and recycled endoglucanase. Fresh endoglucanase preferentially occupied active sites on cellulose surface, hydrolyzed amorphous region, and followed by degrading fibrils to saccharides together with recycled endoglucanase. This hypothesis was evidenced by increase of saccharides concentration when fresh endoglucanase was added. This study aims to provide theoretical support to decrease endoglucanase cost for deconstruction of fibers to fibrils in industrial manufacture. [ABSTRACT FROM AUTHOR]