Fibrous matrix of cellulose was obtained by wet-type electrospinning of cellulose in ionic liquid, 1-butyl-3-methylimidazolium acetate (BMIMAc). The experiments were designed to determine the effects of electric field intensity and the amount of dissolved cellulose on cellulose fiber morphology and diameter. Taking to account practical implications, that is, fiber size and the effectiveness of production, the most effective production of fibers took place using 3% cellulose/BMIMAc solution at electric field of 4.8 kV cm À1 , feed rate of 2.38 ml h À1 . Analysis has shown that cellulose was fully dissolved and consisted purely of regenerated cellulose (type II), while having porosity of 90% and average fiber width of 1.95 ± 0.9 μm. The scanning electron microscopy and micro-computed tomography analyses revealed a robust structural integrity of the formed fibrous matrix, which featured an area density of 85 ± 8 g/ m 2 . The mechanical properties (strength of 12.03 ± 1.1 MPa; strain at break 2.6 ± 0.3%) indicate that in this study strong fibrous cellulose matrix was formed which could be used for the production of biocomposites or as biocompatible scaffolds.

Fiber‐reinforced composites based on natural fibers are promising alternatives for materials made of metal or synthetic polymers. However, the inherent inhomogeneity of natural fibers limits the quality of the respective composites. Man‐made cellulose fibers (MMCFs) prepared from cellulose solutions via wet or dry‐jet wet spinning processes can overcome these limitations. Herein, MMCFs are used to prepare single fiber epoxy composites and UD composites with 20, 30, 40, and 60 wt% fiber loads. The mechanical properties increase gradually with fiber loading. Young's modulus is improved three times while tensile strength doubles at a loading of 60 wt%. Raman spectroscopy is employed to follow conformational changes of the cellulose chains within the fibers upon mechanical deformation of the composites. The shift of the characteristic Raman band under strain indicates the deformation mechanisms in the fiber. Provided stress transfer occurs through the interface, it is a direct measure of the fiber‐matrix interaction, which is investigated herein. The shift rate of the 1095 cm−1 band decreases in single fiber composites compared to the neat fibers and continues to decrease as the fiber loading increased.

The present study concentrates on a series of experiments and numerical analyses for understanding the effects of fiber volume fraction ( VF) and draw ratio ( DR) on the effective elastic properties of unidirectional composites made from an epoxy resin matrix with a continuous fiber reinforcement. Lyocell-type regenerated cellulose filaments (Ioncell) spun with DRs of 3, 6, and 9 were used. In accordance with the specimens in situ, the fibers were modeled as slender solid elements, for which the ratio between the diameter and length was taken to be much less than unity and deposited inside the matrix with the random sequential adsorption algorithm. The embedded element method was thereafter used in the numerical framework due to its computational advantages and reasonable predictions for continuous fiber reinforced composites. Experiments and numerical investigations were carried out, the results of which were compared, and positive trends for both fiber VFs and DRs on the effective properties were observed. The presented experimental and numerical results and models herein are believed to advance the state of the art in the mechanical characterization of composites with continuous fiber reinforcement.

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