All-cellulose composites

T. Nishino and N. Arimoto, All-cellulose composite prepared by selective dissolving of fiber surface. Biomacromolecules, 8 (2007) 2712-2714. 

SOY 09] Soykeabkaew N., Nishino T., Peijs T., All-cellulose composites of regenerated cellulose fibres by surface selective dissolution . Composites A, vol. 40, pp. 321-328, 2009. 

Wang, Y.X., and Chen, L. Y. (2011). Impacts of nanowhisker on formation kinetics and properties of all-cellulose composite gels,... 

Another approach has called upon the coagulation of amorphous cellulose around semi-crystalline fibres (i.e. the preparation of an all-cellulose composite) [19]. 

In another vein, a recent report [95] describes the preparation of an all-cellulose composite by dissolving pretreated ramie fibres in DMAc/LiCl and introducing untreated fibres into the ensuing solution. The composites were then isolated by coagulation with methanol and dried. 

Nishino T, Matsuda I, Hirao K (2004) All-cellulose composite. Macromolecules 37 (20) 7683-7687... 

A better mechanical performance of the all-cellulosic composites reported here could also be achieved taking advantage of Uquid crystalline projjerties of aqueous suspensions of acid hydrolysed microdystaUine cellulose (MCC) [43,44]. A chiral ordering of MCC aqueous suspensions was observed for various cellulose origins... 

Soykeabkaew N, Arimoto N et al (2008) All-cellulose composites by selective dissolution of aligned lingo-cellulosic fibers. Compos Sci Technol 68 2201-2207... 

Cellulose is the most abundant biopolymer on earth. It can be used in different applications, namely in the form of fibers, and cellulose can be converted into numerous cellulose derivatives. Cellulose micro- and nanofibers have been the subject of intense research in the field of composites. Cellulose derivatives can show liquid crystalline chiral nematic phases, which can be used for the production of diverse composite systems. All-cellulosic composites based on liquid crystalline cellulosic matrices reinforced by cellulose micro- and nanofibers can show enhanced mechanical properties due to fiber orientation induced by the liquid crystalline matrix. Cellulose-based fibers electrospun from liquid crystalline phases can develop different structures, which are able to mimic the shape of plant tendrils on the nano- and microscale, opening new horizons for ceDulosic membrane applications. 

Alternative routes, due to environmental awareness and increasing interest in sustainable material concepts, have led to the development of bio- and green composites for structural composite applications, the so-called all-polymer composites or self-reinforced polymer composites . These new materials promise to overcome the critical problem of fiber-matrix adhesion in biocomposites by using chemically similar or identical cellulose materials for both matrix and reinforcement and are designated as all-cellulose composites [39, 40]. 

Cellulose is a fascinating biopolymer that has always been used in the production of textile fibers. Due to environmental concerns intense research has been conducted in the past decades in order to substitute traditional carbon or glass fibers used in the production of composites with eco-friendly cellulose fibers. The research in cellulose-based biocomposites is now focused on the concept of self-reinforced nanocomposites. In this sense all-cellulose composites have been investigated showing mechanical properties comparable or even better than those of traditional composites. Cellulose and its derivatives may also show liquid crystalline mesophases, which can be used to produce new and biomimetic materials with distinctive mechanical and optical properties. Most likely, enhanced mechanical properties will be obtained in all-cellulose nanocomposites by taking full advantage of the orientational order, when both the matrix and the fibers are in a liquid crystalline state. 

The partial dissolution process involves the processing of "self-reinforced" or "all-cellulose" composites in which both filler and matrix are cellulosic forms [6]. For CNCs-reinforced cellulose 11 (regenerated cellulose) composites, this process involves the fabrication of neat CNCs film and subsequent partial dissolution (for a set time) of neat CNCs film in a N,N-dimethylacetamide (DMAc) solution for the formation of cellulose 11, followed by immersion (for a set time) in lithium chloride/DMAc solution to selectively dissolve the surfaces of CNCs. Finally, rinsing of partially dissolved film was performed to remove DMAc, and initiation of precipitation of cellulose 11, followed by drying and compression molding. However, these particular "all-cellulose" composites have been prepared by using solution-casting of a suspension mixture of CNCs within a medium of dissolved cellulose [175]. 

More recently, cellulose fibres have been investigated as potential precursors for self-reinforced polymer composites, as well summarised in a review by Eichhom et al. [191]. Numerous authors have reported the use of cellulose fibres from various sources, including wood pulp fibres [192, 193], filter and Kraft paper [194-197], microcrystalline cellulose fibres [198-202], sisal fibres [203, 204], ramie fibres [205], cotton fibres [206], regenerated cellulose (Lyocell) and cellulose fibres spun from an anisotropic phosphoric acid solution (Bocell) [207], and fibres from bacterial cellulose [208]. Two main technologies have been presented to produce these so-called self-reinforced cellulose or all-cellulose composites, and these are, first, the conventional impregnation of cellulose matrix into cellulose fibres and, second, a novel selective dissolution method in which the cellulose fibre surfaces are partially dissolved to form a matrix phase that bonds fibres together. 

Unlike the thermal processing methods for the consolidation of polymers such as PP, which may use selective fibre surface melting, selective dissolution of cellulose fibres partially dissolves the surface layer of cellulose fibres to form a matrix phase of the all-cellulose composites. Analogous to thermal processing methods described earlier, only the surface of the fibre is intended to be affected by the solvent processing and the core of the fibres maintain their structure in order to provide mechanical reinforcement for the final composite. If performed in a controlled manner, this selective surface dissolution concept can result in a continuous... 

In this chapter, among many biofibers, the microstructure and properties of plant-based fibers will be mainly described in comparison with other fibers. In addition, all-cellulose composites and nanocomposites will be discussed to show how they utilize the excellent intrinsic properties of cellulose. 

Vallejos ME, Peresin M, Rojas OJ (2012) All-cellulose composite fibers obtained by electrospinning dispersions of cellulose acetate and cellulose nanoctystals. J Polym Environ 20 1075-1083... 

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