Orientation of cellulose nanowhiskers (CNWs) derived from tunicates, in an all-cellulose nanocomposite, is achieved through the application of a magnetic field. CNWs are incorporated into a dissolved cellulose matrix system and during solvent casting of the nanocomposite a magnetic field is applied to induce their alignment. Unoriented CNW samples, without the presence of a magnetic field, are also produced. The CNWs are found to orient under the action of the magnetic field, leading to enhanced stiffness and strength of the composites, but not to the level that is theoretically predicted for a fully aligned system. Lowering the volume fraction of the CNWs is shown to allow them to orient more readily in the magnetic field, leading to larger relative increases in the mechanical properties. It is shown, using polarized light microscopy, that the all-cellulose composites have a domain structure, with some domains showing pronounced orientation of CNWs and others where no preferred orientation occurs. Raman spectroscopy is used to both follow the position of bands located at ~1095 and ~895 cm(-1) with deformation and also their intensity as a function rotation angle of the specimens. It is shown that these approaches give valuable independent information on the respective molecular deformation and orientation of the CNWs, and the molecules in the matrix phase, in oriented and nonoriented domains of all-cellulose composites. These data are then related to an increase in the level of molecular deformation in the axial direction, as revealed by the Raman technique. Little orientation of the matrix phase is observed under the action of the magnetic field indicating the dominance of the stiff CNWs in governing mechanical properties.

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All-cellulose nanocomposites are produced using dissolved microcrystalline cellulose (MCC) as the matrix and cellulose nanowhiskers (CNWs), produced by acid hydrolysis, as the reinforcement. These nanocomposites are then characterised using X-ray diffraction to determine their crystallinity, and Raman spectroscopy to discriminate the reinforcing phase (cellulose I) from the CNWs and the matrix phase (cellulose II) from the dissolved MCC. Mechanical testing of the composites shows that there is a significant systematic reinforcement of the matrix material with the addition of CNWs. Furthermore, Raman spectroscopy is used to show that distinct spectroscopic bands for each phase within the composite spectrum can be used to discriminate the effects of both reinforcement and matrix. It is shown that a Raman band located approximately at 1095 cm -1 can be used to follow the micromechanical deformation of the CNWs and matrix, whereas another band located at 895 cm -1 arises purely from the matrix. This spectroscopic fingerprint is used to gain insights into the complex interactions occurring in these potentially recyclable composite materials, and offers a way forward to optimising their properties.

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